[ruff UP031] Fix to use format specifiers instead of percent format

bench/bench.py

@@ -8,7 +8,7 @@ if __name__ == "__main__":
     import pytest  # noqa: F401
 
     script = sys.argv[1:] if len(sys.argv) > 1 else ["empty.py"]
-    cProfile.run("pytest.cmdline.main(%r)" % script, "prof")
+    cProfile.run(f"pytest.cmdline.main({script!r})", "prof")
     p = pstats.Stats("prof")
     p.strip_dirs()
     p.sort_stats("cumulative")

doc/en/conf.py

@@ -236,7 +236,7 @@ html_theme = "flask"
 html_title = "pytest documentation"
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
-html_short_title = "pytest-%s" % release
+html_short_title = f"pytest-{release}"
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.

extra/get_issues.py

@@ -60,7 +60,7 @@ def report(issues):
         kind = _get_kind(issue)
         status = issue["state"]
         number = issue["number"]
-        link = "https://github.com/pytest-dev/pytest/issues/%s/" % number
+        link = f"https://github.com/pytest-dev/pytest/issues/{number}/"
         print("----")
         print(status, kind, link)
         print(title)
@@ -69,7 +69,7 @@ def report(issues):
         # print("\n".join(lines[:3]))
         # if len(lines) > 3 or len(body) > 240:
         #    print("...")
-    print("\n\nFound %s open issues" % len(issues))
+    print(f"\n\nFound {len(issues)} open issues")
 
 
 if __name__ == "__main__":

src/_pytest/_code/code.py

@@ -940,7 +940,7 @@ class FormattedExcinfo:
             s = self.get_source(source, line_index, excinfo, short=short)
             lines.extend(s)
             if short:
-                message = "in %s" % (entry.name)
+                message = f"in {entry.name}"
             else:
                 message = excinfo and excinfo.typename or ""
             entry_path = entry.path

src/_pytest/_io/pprint.py

@@ -616,7 +616,7 @@ class PrettyPrinter:
                 vrepr = self._safe_repr(v, context, maxlevels, level)
                 append(f"{krepr}: {vrepr}")
             context.remove(objid)
-            return "{%s}" % ", ".join(components)
+            return "{{{}}}".format(", ".join(components))
 
         if (issubclass(typ, list) and r is list.__repr__) or (
             issubclass(typ, tuple) and r is tuple.__repr__

src/_pytest/_io/terminalwriter.py

@@ -104,7 +104,7 @@ class TerminalWriter:
         if self.hasmarkup:
             esc = [self._esctable[name] for name, on in markup.items() if on]
             if esc:
-                text = "".join("\x1b[%sm" % cod for cod in esc) + text + "\x1b[0m"
+                text = "".join(f"\x1b[{cod}m" for cod in esc) + text + "\x1b[0m"
         return text
 
     def sep(

src/_pytest/_py/path.py

@@ -659,7 +659,7 @@ class LocalPath:
         )
         if "basename" in kw:
             if "purebasename" in kw or "ext" in kw:
-                raise ValueError("invalid specification %r" % kw)
+                raise ValueError(f"invalid specification {kw!r}")
         else:
             pb = kw.setdefault("purebasename", purebasename)
             try:
@@ -705,7 +705,7 @@ class LocalPath:
                     elif name == "ext":
                         res.append(ext)
                     else:
-                        raise ValueError("invalid part specification %r" % name)
+                        raise ValueError(f"invalid part specification {name!r}")
         return res
 
     def dirpath(self, *args, **kwargs):
@@ -1026,7 +1026,7 @@ class LocalPath:
         return self.stat().atime
 
     def __repr__(self):
-        return "local(%r)" % self.strpath
+        return f"local({self.strpath!r})"
 
     def __str__(self):
         """Return string representation of the Path."""

src/_pytest/assertion/rewrite.py

@@ -101,7 +101,7 @@ class AssertionRewritingHook(importlib.abc.MetaPathFinder, importlib.abc.Loader)
         state = self.config.stash[assertstate_key]
         if self._early_rewrite_bailout(name, state):
             return None
-        state.trace("find_module called for: %s" % name)
+        state.trace(f"find_module called for: {name}")
 
         # Type ignored because mypy is confused about the `self` binding here.
         spec = self._find_spec(name, path)  # type: ignore
@@ -273,7 +273,7 @@ class AssertionRewritingHook(importlib.abc.MetaPathFinder, importlib.abc.Loader)
 
         self.config.issue_config_time_warning(
             PytestAssertRewriteWarning(
-                "Module already imported so cannot be rewritten: %s" % name
+                f"Module already imported so cannot be rewritten: {name}"
             ),
             stacklevel=5,
         )
@@ -374,21 +374,21 @@ def _read_pyc(
             return None
         # Check for invalid or out of date pyc file.
         if len(data) != (16):
-            trace("_read_pyc(%s): invalid pyc (too short)" % source)
+            trace(f"_read_pyc({source}): invalid pyc (too short)")
             return None
         if data[:4] != importlib.util.MAGIC_NUMBER:
-            trace("_read_pyc(%s): invalid pyc (bad magic number)" % source)
+            trace(f"_read_pyc({source}): invalid pyc (bad magic number)")
             return None
         if data[4:8] != b"\x00\x00\x00\x00":
-            trace("_read_pyc(%s): invalid pyc (unsupported flags)" % source)
+            trace(f"_read_pyc({source}): invalid pyc (unsupported flags)")
             return None
         mtime_data = data[8:12]
         if int.from_bytes(mtime_data, "little") != mtime & 0xFFFFFFFF:
-            trace("_read_pyc(%s): out of date" % source)
+            trace(f"_read_pyc({source}): out of date")
             return None
         size_data = data[12:16]
         if int.from_bytes(size_data, "little") != size & 0xFFFFFFFF:
-            trace("_read_pyc(%s): invalid pyc (incorrect size)" % source)
+            trace(f"_read_pyc({source}): invalid pyc (incorrect size)")
             return None
         try:
             co = marshal.load(fp)
@@ -396,7 +396,7 @@ def _read_pyc(
             trace(f"_read_pyc({source}): marshal.load error {e}")
             return None
         if not isinstance(co, types.CodeType):
-            trace("_read_pyc(%s): not a code object" % source)
+            trace(f"_read_pyc({source}): not a code object")
             return None
         return co
 

src/_pytest/assertion/util.py

@@ -292,7 +292,7 @@ def _diff_text(left: str, right: str, verbose: int = 0) -> List[str]:
         if i > 42:
             i -= 10  # Provide some context
             explanation = [
-                "Skipping %s identical leading characters in diff, use -v to show" % i
+                f"Skipping {i} identical leading characters in diff, use -v to show"
             ]
             left = left[i:]
             right = right[i:]
@@ -493,7 +493,7 @@ def _compare_eq_dict(
     common = set_left.intersection(set_right)
     same = {k: left[k] for k in common if left[k] == right[k]}
     if same and verbose < 2:
-        explanation += ["Omitting %s identical items, use -vv to show" % len(same)]
+        explanation += [f"Omitting {len(same)} identical items, use -vv to show"]
     elif same:
         explanation += ["Common items:"]
         explanation += highlighter(pprint.pformat(same)).splitlines()
@@ -560,7 +560,7 @@ def _compare_eq_cls(
     if same or diff:
         explanation += [""]
     if same and verbose < 2:
-        explanation.append("Omitting %s identical items, use -vv to show" % len(same))
+        explanation.append(f"Omitting {len(same)} identical items, use -vv to show")
     elif same:
         explanation += ["Matching attributes:"]
         explanation += highlighter(pprint.pformat(same)).splitlines()
@@ -590,7 +590,7 @@ def _notin_text(term: str, text: str, verbose: int = 0) -> List[str]:
     tail = text[index + len(term) :]
     correct_text = head + tail
     diff = _diff_text(text, correct_text, verbose)
-    newdiff = ["%s is contained here:" % saferepr(term, maxsize=42)]
+    newdiff = [f"{saferepr(term, maxsize=42)} is contained here:"]
     for line in diff:
         if line.startswith("Skipping"):
             continue

src/_pytest/cacheprovider.py

@@ -332,7 +332,7 @@ class LFPlugin:
 
     def pytest_report_collectionfinish(self) -> Optional[str]:
         if self.active and self.config.getoption("verbose") >= 0:
-            return "run-last-failure: %s" % self._report_status
+            return f"run-last-failure: {self._report_status}"
         return None
 
     def pytest_runtest_logreport(self, report: TestReport) -> None:
@@ -588,21 +588,21 @@ def cacheshow(config: Config, session: Session) -> int:
     dummy = object()
     basedir = config.cache._cachedir
     vdir = basedir / Cache._CACHE_PREFIX_VALUES
-    tw.sep("-", "cache values for %r" % glob)
+    tw.sep("-", f"cache values for {glob!r}")
     for valpath in sorted(x for x in vdir.rglob(glob) if x.is_file()):
         key = str(valpath.relative_to(vdir))
         val = config.cache.get(key, dummy)
         if val is dummy:
-            tw.line("%s contains unreadable content, will be ignored" % key)
+            tw.line(f"{key} contains unreadable content, will be ignored")
         else:
-            tw.line("%s contains:" % key)
+            tw.line(f"{key} contains:")
             for line in pformat(val).splitlines():
                 tw.line("  " + line)
 
     ddir = basedir / Cache._CACHE_PREFIX_DIRS
     if ddir.is_dir():
         contents = sorted(ddir.rglob(glob))
-        tw.sep("-", "cache directories for %r" % glob)
+        tw.sep("-", f"cache directories for {glob!r}")
         for p in contents:
             # if p.is_dir():
             #    print("%s/" % p.relative_to(basedir))

src/_pytest/capture.py

@@ -738,7 +738,7 @@ class CaptureManager:
         if self.is_globally_capturing():
             return "global"
         if self._capture_fixture:
-            return "fixture %s" % self._capture_fixture.request.fixturename
+            return f"fixture {self._capture_fixture.request.fixturename}"
         return False
 
     # Global capturing control

src/_pytest/config/__init__.py

@@ -798,7 +798,7 @@ class PytestPluginManager(PluginManager):
         if arg.startswith("no:"):
             name = arg[3:]
             if name in essential_plugins:
-                raise UsageError("plugin %s cannot be disabled" % name)
+                raise UsageError(f"plugin {name} cannot be disabled")
 
             # PR #4304: remove stepwise if cacheprovider is blocked.
             if name == "cacheprovider":
@@ -847,9 +847,9 @@ class PytestPluginManager(PluginManager):
         # "terminal" or "capture".  Those plugins are registered under their
         # basename for historic purposes but must be imported with the
         # _pytest prefix.
-        assert isinstance(modname, str), (
+        assert isinstance(
-            "module name as text required, got %r" % modname
+            modname, str
-        )
+        ), f"module name as text required, got {modname!r}"
         if self.is_blocked(modname) or self.get_plugin(modname) is not None:
             return
 
@@ -892,8 +892,7 @@ def _get_plugin_specs_as_list(
     if isinstance(specs, collections.abc.Sequence):
         return list(specs)
     raise UsageError(
-        "Plugins may be specified as a sequence or a ','-separated string of plugin names. Got: %r"
+        f"Plugins may be specified as a sequence or a ','-separated string of plugin names. Got: {specs!r}"
-        % specs
     )
 
 
@@ -1185,7 +1184,7 @@ class Config:
         res = self.hook.pytest_internalerror(excrepr=excrepr, excinfo=excinfo)
         if not any(res):
             for line in str(excrepr).split("\n"):
-                sys.stderr.write("INTERNALERROR> %s\n" % line)
+                sys.stderr.write(f"INTERNALERROR> {line}\n")
                 sys.stderr.flush()
 
     def cwd_relative_nodeid(self, nodeid: str) -> str:
@@ -1435,7 +1434,7 @@ class Config:
 
             if not isinstance(minver, str):
                 raise pytest.UsageError(
-                    "%s: 'minversion' must be a single value" % self.inipath
+                    f"{self.inipath}: 'minversion' must be a single value"
                 )
 
             if Version(minver) > Version(pytest.__version__):

src/_pytest/config/argparsing.py

@@ -313,23 +313,23 @@ class Argument:
         for opt in opts:
             if len(opt) < 2:
                 raise ArgumentError(
-                    "invalid option string %r: "
+                    f"invalid option string {opt!r}: "
-                    "must be at least two characters long" % opt,
+                    "must be at least two characters long",
                     self,
                 )
             elif len(opt) == 2:
                 if not (opt[0] == "-" and opt[1] != "-"):
                     raise ArgumentError(
-                        "invalid short option string %r: "
+                        f"invalid short option string {opt!r}: "
-                        "must be of the form -x, (x any non-dash char)" % opt,
+                        "must be of the form -x, (x any non-dash char)",
                         self,
                     )
                 self._short_opts.append(opt)
             else:
                 if not (opt[0:2] == "--" and opt[2] != "-"):
                     raise ArgumentError(
-                        "invalid long option string %r: "
+                        f"invalid long option string {opt!r}: "
-                        "must start with --, followed by non-dash" % opt,
+                        "must start with --, followed by non-dash",
                         self,
                     )
                 self._long_opts.append(opt)
@@ -383,7 +383,7 @@ class OptionGroup:
             name for opt in self.options for name in opt.names()
         )
         if conflict:
-            raise ValueError("option names %s already added" % conflict)
+            raise ValueError(f"option names {conflict} already added")
         option = Argument(*opts, **attrs)
         self._addoption_instance(option, shortupper=False)
 
@@ -441,7 +441,9 @@ class MyOptionParser(argparse.ArgumentParser):
         if unrecognized:
             for arg in unrecognized:
                 if arg and arg[0] == "-":
-                    lines = ["unrecognized arguments: %s" % (" ".join(unrecognized))]
+                    lines = [
+                        "unrecognized arguments: {}".format(" ".join(unrecognized))
+                    ]
                     for k, v in sorted(self.extra_info.items()):
                         lines.append(f"  {k}: {v}")
                     self.error("\n".join(lines))
@@ -520,7 +522,7 @@ class DropShorterLongHelpFormatter(argparse.HelpFormatter):
                 continue
             if not option.startswith("--"):
                 raise ArgumentError(
-                    'long optional argument without "--": [%s]' % (option), option
+                    f'long optional argument without "--": [{option}]', option
                 )
             xxoption = option[2:]
             shortened = xxoption.replace("-", "")

src/_pytest/debugging.py

@@ -181,8 +181,7 @@ class pytestPDB:
                         else:
                             tw.sep(
                                 ">",
-                                "PDB continue (IO-capturing resumed for %s)"
+                                f"PDB continue (IO-capturing resumed for {capturing})",
-                                % capturing,
                             )
                         assert capman is not None
                         capman.resume()

src/_pytest/doctest.py

@@ -374,7 +374,7 @@ class DoctestItem(Item):
                 ).split("\n")
             else:
                 inner_excinfo = ExceptionInfo.from_exc_info(failure.exc_info)
-                lines += ["UNEXPECTED EXCEPTION: %s" % repr(inner_excinfo.value)]
+                lines += [f"UNEXPECTED EXCEPTION: {inner_excinfo.value!r}"]
                 lines += [
                     x.strip("\n") for x in traceback.format_exception(*failure.exc_info)
                 ]
@@ -382,7 +382,7 @@ class DoctestItem(Item):
         return ReprFailDoctest(reprlocation_lines)
 
     def reportinfo(self) -> Tuple[Union["os.PathLike[str]", str], Optional[int], str]:
-        return self.path, self.dtest.lineno, "[doctest] %s" % self.name
+        return self.path, self.dtest.lineno, f"[doctest] {self.name}"
 
 
 def _get_flag_lookup() -> Dict[str, int]:
@@ -563,7 +563,7 @@ class DoctestModule(Module):
             module = self.obj
         except Collector.CollectError:
             if self.config.getvalue("doctest_ignore_import_errors"):
-                skip("unable to import module %r" % self.path)
+                skip(f"unable to import module {self.path!r}")
             else:
                 raise
 

src/_pytest/fixtures.py

@@ -675,7 +675,7 @@ class TopRequest(FixtureRequest):
         return self._pyfuncitem
 
     def __repr__(self) -> str:
-        return "<FixtureRequest for %r>" % (self.node)
+        return f"<FixtureRequest for {self.node!r}>"
 
     def _fillfixtures(self) -> None:
         item = self._pyfuncitem
@@ -1897,7 +1897,7 @@ def _showfixtures_main(config: Config, session: "Session") -> None:
             continue
         tw.write(f"{argname}", green=True)
         if fixturedef.scope != "function":
-            tw.write(" [%s scope]" % fixturedef.scope, cyan=True)
+            tw.write(f" [{fixturedef.scope} scope]", cyan=True)
         tw.write(f" -- {prettypath}", yellow=True)
         tw.write("\n")
         doc = inspect.getdoc(fixturedef.func)

src/_pytest/helpconfig.py

@@ -121,11 +121,11 @@ def pytest_cmdline_parse() -> Generator[None, Config, Config]:
         )
         config.trace.root.setwriter(debugfile.write)
         undo_tracing = config.pluginmanager.enable_tracing()
-        sys.stderr.write("writing pytest debug information to %s\n" % path)
+        sys.stderr.write(f"writing pytest debug information to {path}\n")
 
         def unset_tracing() -> None:
             debugfile.close()
-            sys.stderr.write("wrote pytest debug information to %s\n" % debugfile.name)
+            sys.stderr.write(f"wrote pytest debug information to {debugfile.name}\n")
             config.trace.root.setwriter(None)
             undo_tracing()
 
@@ -185,7 +185,7 @@ def showhelp(config: Config) -> None:
         if help is None:
             raise TypeError(f"help argument cannot be None for {name}")
         spec = f"{name} ({type}):"
-        tw.write("  %s" % spec)
+        tw.write(f"  {spec}")
         spec_len = len(spec)
         if spec_len > (indent_len - 3):
             # Display help starting at a new line.

src/_pytest/junitxml.py

@@ -53,9 +53,9 @@ def bin_xml_escape(arg: object) -> str:
     def repl(matchobj: Match[str]) -> str:
         i = ord(matchobj.group())
         if i <= 0xFF:
-            return "#x%02X" % i
+            return f"#x{i:02X}"
         else:
-            return "#x%04X" % i
+            return f"#x{i:04X}"
 
     # The spec range of valid chars is:
     # Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
@@ -149,7 +149,7 @@ class _NodeReporter:
         self.attrs = temp_attrs
 
     def to_xml(self) -> ET.Element:
-        testcase = ET.Element("testcase", self.attrs, time="%.3f" % self.duration)
+        testcase = ET.Element("testcase", self.attrs, time=f"{self.duration:.3f}")
         properties = self.make_properties_node()
         if properties is not None:
             testcase.append(properties)
@@ -670,7 +670,7 @@ class LogXML:
                 failures=str(self.stats["failure"]),
                 skipped=str(self.stats["skipped"]),
                 tests=str(numtests),
-                time="%.3f" % suite_time_delta,
+                time=f"{suite_time_delta:.3f}",
                 timestamp=datetime.fromtimestamp(self.suite_start_time).isoformat(),
                 hostname=platform.node(),
             )

src/_pytest/mark/__init__.py

@@ -122,7 +122,7 @@ def pytest_cmdline_main(config: Config) -> Optional[Union[int, ExitCode]]:
             parts = line.split(":", 1)
             name = parts[0]
             rest = parts[1] if len(parts) == 2 else ""
-            tw.write("@pytest.mark.%s:" % name, bold=True)
+            tw.write(f"@pytest.mark.{name}:", bold=True)
             tw.line(rest)
             tw.line()
         config._ensure_unconfigure()

src/_pytest/mark/structures.py

@@ -552,9 +552,9 @@ class MarkGenerator:
                     fail(f"Unknown '{name}' mark, did you mean 'parametrize'?")
 
                 warnings.warn(
-                    "Unknown pytest.mark.%s - is this a typo?  You can register "
+                    f"Unknown pytest.mark.{name} - is this a typo?  You can register "
                     "custom marks to avoid this warning - for details, see "
-                    "https://docs.pytest.org/en/stable/how-to/mark.html" % name,
+                    "https://docs.pytest.org/en/stable/how-to/mark.html",
                     PytestUnknownMarkWarning,
                     2,
                 )

src/_pytest/pastebin.py

@@ -65,7 +65,7 @@ def pytest_unconfigure(config: Config) -> None:
         # Write summary.
         tr.write_sep("=", "Sending information to Paste Service")
         pastebinurl = create_new_paste(sessionlog)
-        tr.write_line("pastebin session-log: %s\n" % pastebinurl)
+        tr.write_line(f"pastebin session-log: {pastebinurl}\n")
 
 
 def create_new_paste(contents: Union[str, bytes]) -> str:
@@ -85,7 +85,7 @@ def create_new_paste(contents: Union[str, bytes]) -> str:
             urlopen(url, data=urlencode(params).encode("ascii")).read().decode("utf-8")
         )
     except OSError as exc_info:  # urllib errors
-        return "bad response: %s" % exc_info
+        return f"bad response: {exc_info}"
     m = re.search(r'href="/raw/(\w+)"', response)
     if m:
         return f"{url}/show/{m.group(1)}"

src/_pytest/pytester.py

@@ -182,13 +182,13 @@ class LsofFdLeakChecker:
             leaked_files = [t for t in lines2 if t[0] in new_fds]
             if leaked_files:
                 error = [
-                    "***** %s FD leakage detected" % len(leaked_files),
+                    f"***** {len(leaked_files)} FD leakage detected",
                     *(str(f) for f in leaked_files),
                     "*** Before:",
                     *(str(f) for f in lines1),
                     "*** After:",
                     *(str(f) for f in lines2),
-                    "***** %s FD leakage detected" % len(leaked_files),
+                    f"***** {len(leaked_files)} FD leakage detected",
                     "*** function {}:{}: {} ".format(*item.location),
                     "See issue #2366",
                 ]
@@ -313,7 +313,7 @@ class HookRecorder:
                 del self.calls[i]
                 return call
         lines = [f"could not find call {name!r}, in:"]
-        lines.extend(["  %s" % x for x in self.calls])
+        lines.extend([f"  {x}" for x in self.calls])
         fail("\n".join(lines))
 
     def getcall(self, name: str) -> RecordedHookCall:
@@ -1204,7 +1204,9 @@ class Pytester:
             if str(x).startswith("--basetemp"):
                 break
         else:
-            new_args.append("--basetemp=%s" % self.path.parent.joinpath("basetemp"))
+            new_args.append(
+                "--basetemp={}".format(self.path.parent.joinpath("basetemp"))
+            )
         return new_args
 
     def parseconfig(self, *args: Union[str, "os.PathLike[str]"]) -> Config:
@@ -1485,7 +1487,7 @@ class Pytester:
         """
         __tracebackhide__ = True
         p = make_numbered_dir(root=self.path, prefix="runpytest-", mode=0o700)
-        args = ("--basetemp=%s" % p, *args)
+        args = (f"--basetemp={p}", *args)
         plugins = [x for x in self.plugins if isinstance(x, str)]
         if plugins:
             args = ("-p", plugins[0], *args)
@@ -1593,7 +1595,7 @@ class LineMatcher:
                     self._log("matched: ", repr(line))
                     break
             else:
-                msg = "line %r not found in output" % line
+                msg = f"line {line!r} not found in output"
                 self._log(msg)
                 self._fail(msg)
 
@@ -1605,7 +1607,7 @@ class LineMatcher:
         for i, line in enumerate(self.lines):
             if fnline == line or fnmatch(line, fnline):
                 return self.lines[i + 1 :]
-        raise ValueError("line %r not found in output" % fnline)
+        raise ValueError(f"line {fnline!r} not found in output")
 
     def _log(self, *args) -> None:
         self._log_output.append(" ".join(str(x) for x in args))
@@ -1690,7 +1692,7 @@ class LineMatcher:
                     started = True
                     break
                 elif match_func(nextline, line):
-                    self._log("%s:" % match_nickname, repr(line))
+                    self._log(f"{match_nickname}:", repr(line))
                     self._log(
                         "{:>{width}}".format("with:", width=wnick), repr(nextline)
                     )

src/_pytest/python.py

@@ -224,7 +224,7 @@ def pytest_pycollect_makeitem(
             filename, lineno = getfslineno(obj)
             warnings.warn_explicit(
                 message=PytestCollectionWarning(
-                    "cannot collect %r because it is not a function." % name
+                    f"cannot collect {name!r} because it is not a function."
                 ),
                 category=None,
                 filename=str(filename),

src/_pytest/reports.py

@@ -232,10 +232,10 @@ def _report_unserialization_failure(
     url = "https://github.com/pytest-dev/pytest/issues"
     stream = StringIO()
     pprint("-" * 100, stream=stream)
-    pprint("INTERNALERROR: Unknown entry type returned: %s" % type_name, stream=stream)
+    pprint(f"INTERNALERROR: Unknown entry type returned: {type_name}", stream=stream)
-    pprint("report_name: %s" % report_class, stream=stream)
+    pprint(f"report_name: {report_class}", stream=stream)
     pprint(reportdict, stream=stream)
-    pprint("Please report this bug at %s" % url, stream=stream)
+    pprint(f"Please report this bug at {url}", stream=stream)
     pprint("-" * 100, stream=stream)
     raise RuntimeError(stream.getvalue())
 

src/_pytest/runner.py

@@ -90,7 +90,7 @@ def pytest_terminal_summary(terminalreporter: "TerminalReporter") -> None:
     if not durations:
         tr.write_sep("=", "slowest durations")
     else:
-        tr.write_sep("=", "slowest %s durations" % durations)
+        tr.write_sep("=", f"slowest {durations} durations")
         dlist = dlist[:durations]
 
     for i, rep in enumerate(dlist):

src/_pytest/skipping.py

@@ -117,7 +117,7 @@ def evaluate_condition(item: Item, mark: Mark, condition: object) -> Tuple[bool,
             result = eval(condition_code, globals_)
         except SyntaxError as exc:
             msglines = [
-                "Error evaluating %r condition" % mark.name,
+                f"Error evaluating {mark.name!r} condition",
                 "    " + condition,
                 "    " + " " * (exc.offset or 0) + "^",
                 "SyntaxError: invalid syntax",
@@ -125,7 +125,7 @@ def evaluate_condition(item: Item, mark: Mark, condition: object) -> Tuple[bool,
             fail("\n".join(msglines), pytrace=False)
         except Exception as exc:
             msglines = [
-                "Error evaluating %r condition" % mark.name,
+                f"Error evaluating {mark.name!r} condition",
                 "    " + condition,
                 *traceback.format_exception_only(type(exc), exc),
             ]
@@ -137,7 +137,7 @@ def evaluate_condition(item: Item, mark: Mark, condition: object) -> Tuple[bool,
             result = bool(condition)
         except Exception as exc:
             msglines = [
-                "Error evaluating %r condition as a boolean" % mark.name,
+                f"Error evaluating {mark.name!r} condition as a boolean",
                 *traceback.format_exception_only(type(exc), exc),
             ]
             fail("\n".join(msglines), pytrace=False)
@@ -149,7 +149,7 @@ def evaluate_condition(item: Item, mark: Mark, condition: object) -> Tuple[bool,
         else:
             # XXX better be checked at collection time
             msg = (
-                "Error evaluating %r: " % mark.name
+                f"Error evaluating {mark.name!r}: "
                 + "you need to specify reason=STRING when using booleans as conditions."
             )
             fail(msg, pytrace=False)

src/_pytest/terminal.py

@@ -640,7 +640,7 @@ class TerminalReporter:
                     self._write_progress_information_filling_space()
             else:
                 self.ensure_newline()
-                self._tw.write("[%s]" % rep.node.gateway.id)
+                self._tw.write(f"[{rep.node.gateway.id}]")
                 if self._show_progress_info:
                     self._tw.write(
                         self._get_progress_information_message() + " ", cyan=True
@@ -818,7 +818,9 @@ class TerminalReporter:
 
         plugininfo = config.pluginmanager.list_plugin_distinfo()
         if plugininfo:
-            result.append("plugins: %s" % ", ".join(_plugin_nameversions(plugininfo)))
+            result.append(
+                "plugins: {}".format(", ".join(_plugin_nameversions(plugininfo)))
+            )
         return result
 
     def pytest_collection_finish(self, session: "Session") -> None:

testing/_py/test_local.py

@@ -551,7 +551,7 @@ def batch_make_numbered_dirs(rootdir, repeats):
     for i in range(repeats):
         dir_ = local.make_numbered_dir(prefix="repro-", rootdir=rootdir)
         file_ = dir_.join("foo")
-        file_.write_text("%s" % i, encoding="utf-8")
+        file_.write_text(f"{i}", encoding="utf-8")
         actual = int(file_.read_text(encoding="utf-8"))
         assert (
             actual == i
@@ -563,9 +563,9 @@ def batch_make_numbered_dirs(rootdir, repeats):
 class TestLocalPath(CommonFSTests):
     def test_join_normpath(self, tmpdir):
         assert tmpdir.join(".") == tmpdir
-        p = tmpdir.join("../%s" % tmpdir.basename)
+        p = tmpdir.join(f"../{tmpdir.basename}")
         assert p == tmpdir
-        p = tmpdir.join("..//%s/" % tmpdir.basename)
+        p = tmpdir.join(f"..//{tmpdir.basename}/")
         assert p == tmpdir
 
     @skiponwin32
@@ -722,7 +722,7 @@ class TestLocalPath(CommonFSTests):
 
     @pytest.mark.parametrize("bin", (False, True))
     def test_dump(self, tmpdir, bin):
-        path = tmpdir.join("dumpfile%s" % int(bin))
+        path = tmpdir.join(f"dumpfile{int(bin)}")
         try:
             d = {"answer": 42}
             path.dump(d, bin=bin)

testing/acceptance_test.py

@@ -400,7 +400,7 @@ class TestGeneralUsage:
 
         for name, value in vars(hookspec).items():
             if name.startswith("pytest_"):
-                assert value.__doc__, "no docstring for %s" % name
+                assert value.__doc__, f"no docstring for {name}"
 
     def test_initialization_error_issue49(self, pytester: Pytester) -> None:
         pytester.makeconftest(
@@ -973,7 +973,7 @@ class TestDurations:
         for x in tested:
             for y in ("call",):  # 'setup', 'call', 'teardown':
                 for line in result.stdout.lines:
-                    if ("test_%s" % x) in line and y in line:
+                    if (f"test_{x}") in line and y in line:
                         break
                 else:
                     raise AssertionError(f"not found {x} {y}")
@@ -986,7 +986,7 @@ class TestDurations:
         for x in "123":
             for y in ("call",):  # 'setup', 'call', 'teardown':
                 for line in result.stdout.lines:
-                    if ("test_%s" % x) in line and y in line:
+                    if (f"test_{x}") in line and y in line:
                         break
                 else:
                     raise AssertionError(f"not found {x} {y}")

testing/code/test_excinfo.py

@@ -1406,7 +1406,7 @@ raise ValueError()
             mod.f()
 
         # emulate the issue described in #1984
-        attr = "__%s__" % reason
+        attr = f"__{reason}__"
         getattr(excinfo.value, attr).__traceback__ = None
 
         r = excinfo.getrepr()

testing/freeze/tox_run.py

@@ -10,4 +10,4 @@ if __name__ == "__main__":
     executable = os.path.join(os.getcwd(), "dist", "runtests_script", "runtests_script")
     if sys.platform.startswith("win"):
         executable += ".exe"
-    sys.exit(os.system("%s tests" % executable))
+    sys.exit(os.system(f"{executable} tests"))

testing/io/test_saferepr.py

@@ -144,7 +144,7 @@ def test_big_repr():
 def test_repr_on_newstyle() -> None:
     class Function:
         def __repr__(self):
-            return "<%s>" % (self.name)  # type: ignore[attr-defined]
+            return f"<{self.name}>"  # type: ignore[attr-defined]
 
     assert saferepr(Function())
 

testing/python/collect.py

@@ -36,9 +36,9 @@ class TestModule:
             [
                 "*import*mismatch*",
                 "*imported*test_whatever*",
-                "*%s*" % p1,
+                f"*{p1}*",
                 "*not the same*",
-                "*%s*" % p2,
+                f"*{p2}*",
                 "*HINT*",
             ]
         )

testing/python/fixtures.py

@@ -2268,18 +2268,17 @@ class TestFixtureMarker:
         This was a regression introduced in the fix for #736.
         """
         pytester.makepyfile(
-            """
+            f"""
             import pytest
 
             @pytest.fixture(params=[1, 2])
             def fixt(request):
                 return request.param
 
-            @pytest.mark.parametrize(%s, [(3, 'x'), (4, 'x')])
+            @pytest.mark.parametrize({param_args}, [(3, 'x'), (4, 'x')])
             def test_foo(fixt, val):
                 pass
         """
-            % param_args
         )
         reprec = pytester.inline_run()
         reprec.assertoutcome(passed=2)

testing/test_assertion.py

@@ -101,7 +101,7 @@ class TestImportHookInstallation:
             """,
         }
         pytester.makepyfile(**contents)
-        result = pytester.runpytest_subprocess("--assert=%s" % mode)
+        result = pytester.runpytest_subprocess(f"--assert={mode}")
         if mode == "plain":
             expected = "E       AssertionError"
         elif mode == "rewrite":
@@ -163,7 +163,7 @@ class TestImportHookInstallation:
             """,
         }
         pytester.makepyfile(**contents)
-        result = pytester.runpytest_subprocess("--assert=%s" % mode)
+        result = pytester.runpytest_subprocess(f"--assert={mode}")
         if mode == "plain":
             expected = "E       AssertionError"
         elif mode == "rewrite":
@@ -280,7 +280,7 @@ class TestImportHookInstallation:
         }
         pytester.makepyfile(**contents)
         result = pytester.run(
-            sys.executable, "mainwrapper.py", "-s", "--assert=%s" % mode
+            sys.executable, "mainwrapper.py", "-s", f"--assert={mode}"
         )
         if mode == "plain":
             expected = "E       AssertionError"

testing/test_assertrewrite.py

@@ -308,9 +308,7 @@ class TestAssertionRewrite:
         )
         result = pytester.runpytest()
         assert result.ret == 1
-        result.stdout.fnmatch_lines(
+        result.stdout.fnmatch_lines([f"*AssertionError*{(1, 2)!r}*", "*assert 1 == 2*"])
-            ["*AssertionError*%s*" % repr((1, 2)), "*assert 1 == 2*"]
-        )
 
     def test_assertion_message_expr(self, pytester: Pytester) -> None:
         pytester.makepyfile(
@@ -908,7 +906,7 @@ def test_rewritten():
                 assert test_optimized.__doc__ is None"""
         )
         p = make_numbered_dir(root=Path(pytester.path), prefix="runpytest-")
-        tmp = "--basetemp=%s" % p
+        tmp = f"--basetemp={p}"
         with monkeypatch.context() as mp:
             mp.setenv("PYTHONOPTIMIZE", "2")
             mp.delenv("PYTHONDONTWRITEBYTECODE", raising=False)

testing/test_cacheprovider.py

@@ -191,7 +191,7 @@ def test_cache_reportheader(
         monkeypatch.delenv("TOX_ENV_DIR", raising=False)
         expected = ".pytest_cache"
     result = pytester.runpytest("-v")
-    result.stdout.fnmatch_lines(["cachedir: %s" % expected])
+    result.stdout.fnmatch_lines([f"cachedir: {expected}"])
 
 
 def test_cache_reportheader_external_abspath(

testing/test_capture.py

@@ -103,16 +103,15 @@ class TestCaptureManager:
 def test_capturing_unicode(pytester: Pytester, method: str) -> None:
     obj = "'b\u00f6y'"
     pytester.makepyfile(
-        """\
+        f"""\
         # taken from issue 227 from nosetests
         def test_unicode():
             import sys
             print(sys.stdout)
-            print(%s)
+            print({obj})
         """
-        % obj
     )
-    result = pytester.runpytest("--capture=%s" % method)
+    result = pytester.runpytest(f"--capture={method}")
     result.stdout.fnmatch_lines(["*1 passed*"])
 
 
@@ -124,7 +123,7 @@ def test_capturing_bytes_in_utf8_encoding(pytester: Pytester, method: str) -> No
             print('b\\u00f6y')
         """
     )
-    result = pytester.runpytest("--capture=%s" % method)
+    result = pytester.runpytest(f"--capture={method}")
     result.stdout.fnmatch_lines(["*1 passed*"])
 
 

testing/test_collection.py

@@ -275,14 +275,14 @@ class TestCollectFS:
         # collects the tests
         for dirname in ("a", "b", "c"):
             items, reprec = pytester.inline_genitems(tmp_path.joinpath(dirname))
-            assert [x.name for x in items] == ["test_%s" % dirname]
+            assert [x.name for x in items] == [f"test_{dirname}"]
 
         # changing cwd to each subdirectory and running pytest without
         # arguments collects the tests in that directory normally
         for dirname in ("a", "b", "c"):
             monkeypatch.chdir(pytester.path.joinpath(dirname))
             items, reprec = pytester.inline_genitems()
-            assert [x.name for x in items] == ["test_%s" % dirname]
+            assert [x.name for x in items] == [f"test_{dirname}"]
 
 
 class TestCollectPluginHookRelay:
@@ -572,7 +572,7 @@ class TestSession:
     def test_collect_custom_nodes_multi_id(self, pytester: Pytester) -> None:
         p = pytester.makepyfile("def test_func(): pass")
         pytester.makeconftest(
-            """
+            f"""
             import pytest
             class SpecialItem(pytest.Item):
                 def runtest(self):
@@ -581,10 +581,9 @@ class TestSession:
                 def collect(self):
                     return [SpecialItem.from_parent(name="check", parent=self)]
             def pytest_collect_file(file_path, parent):
-                if file_path.name == %r:
+                if file_path.name == {p.name!r}:
                     return SpecialFile.from_parent(path=file_path, parent=parent)
         """
-            % p.name
         )
         id = p.name
 
@@ -862,7 +861,7 @@ def test_matchnodes_two_collections_same_file(pytester: Pytester) -> None:
     result = pytester.runpytest()
     assert result.ret == 0
     result.stdout.fnmatch_lines(["*2 passed*"])
-    res = pytester.runpytest("%s::item2" % p.name)
+    res = pytester.runpytest(f"{p.name}::item2")
     res.stdout.fnmatch_lines(["*1 passed*"])
 
 
@@ -1444,7 +1443,7 @@ def test_collect_symlink_out_of_tree(pytester: Pytester) -> None:
     symlink_to_sub = out_of_tree.joinpath("symlink_to_sub")
     symlink_or_skip(sub, symlink_to_sub)
     os.chdir(sub)
-    result = pytester.runpytest("-vs", "--rootdir=%s" % sub, symlink_to_sub)
+    result = pytester.runpytest("-vs", f"--rootdir={sub}", symlink_to_sub)
     result.stdout.fnmatch_lines(
         [
             # Should not contain "sub/"!

testing/test_config.py

@@ -67,13 +67,12 @@ class TestParseIni:
         p1 = pytester.makepyfile("def test(): pass")
         pytester.makefile(
             ".cfg",
-            setup="""
+            setup=f"""
                 [tool:pytest]
-                testpaths=%s
+                testpaths={p1.name}
                 [pytest]
                 testpaths=ignored
-        """
+        """,
-            % p1.name,
         )
         result = pytester.runpytest()
         result.stdout.fnmatch_lines(["configfile: setup.cfg", "* 1 passed in *"])
@@ -838,11 +837,10 @@ class TestConfigAPI:
         )
         if str_val != "no-ini":
             pytester.makeini(
-                """
+                f"""
                 [pytest]
-                strip=%s
+                strip={str_val}
             """
-                % str_val
             )
         config = pytester.parseconfig()
         assert config.getini("strip") is bool_val
@@ -1290,8 +1288,8 @@ def test_invalid_options_show_extra_information(pytester: Pytester) -> None:
     result.stderr.fnmatch_lines(
         [
             "*error: unrecognized arguments: --invalid-option*",
-            "*  inifile: %s*" % pytester.path.joinpath("tox.ini"),
+            "*  inifile: {}*".format(pytester.path.joinpath("tox.ini")),
-            "*  rootdir: %s*" % pytester.path,
+            f"*  rootdir: {pytester.path}*",
         ]
     )
 
@@ -1423,8 +1421,8 @@ def test_load_initial_conftest_last_ordering(_config_for_test):
 def test_get_plugin_specs_as_list() -> None:
     def exp_match(val: object) -> str:
         return (
-            "Plugins may be specified as a sequence or a ','-separated string of plugin names. Got: %s"
+            f"Plugins may be specified as a sequence or a ','-separated string "
-            % re.escape(repr(val))
+            f"of plugin names. Got: {re.escape(repr(val))}"
         )
 
     with pytest.raises(pytest.UsageError, match=exp_match({"foo"})):
@@ -1837,10 +1835,10 @@ class TestOverrideIniArgs:
         self, monkeypatch: MonkeyPatch, _config_for_test, _sys_snapshot
     ) -> None:
         cache_dir = ".custom_cache"
-        monkeypatch.setenv("PYTEST_ADDOPTS", "-o cache_dir=%s" % cache_dir)
+        monkeypatch.setenv("PYTEST_ADDOPTS", f"-o cache_dir={cache_dir}")
         config = _config_for_test
         config._preparse([], addopts=True)
-        assert config._override_ini == ["cache_dir=%s" % cache_dir]
+        assert config._override_ini == [f"cache_dir={cache_dir}"]
 
     def test_addopts_from_env_not_concatenated(
         self, monkeypatch: MonkeyPatch, _config_for_test
@@ -2048,7 +2046,7 @@ def test_invocation_args(pytester: Pytester) -> None:
 )
 def test_config_blocked_default_plugins(pytester: Pytester, plugin: str) -> None:
     p = pytester.makepyfile("def test(): pass")
-    result = pytester.runpytest(str(p), "-pno:%s" % plugin)
+    result = pytester.runpytest(str(p), f"-pno:{plugin}")
 
     if plugin == "python":
         assert result.ret == ExitCode.USAGE_ERROR
@@ -2065,7 +2063,7 @@ def test_config_blocked_default_plugins(pytester: Pytester, plugin: str) -> None
         result.stdout.fnmatch_lines(["* 1 passed in *"])
 
     p = pytester.makepyfile("def test(): assert 0")
-    result = pytester.runpytest(str(p), "-pno:%s" % plugin)
+    result = pytester.runpytest(str(p), f"-pno:{plugin}")
     assert result.ret == ExitCode.TESTS_FAILED
     if plugin != "terminal":
         result.stdout.fnmatch_lines(["* 1 failed in *"])

testing/test_conftest.py

@@ -280,7 +280,7 @@ def test_conftest_confcutdir(pytester: Pytester) -> None:
         ),
         encoding="utf-8",
     )
-    result = pytester.runpytest("-h", "--confcutdir=%s" % x, x)
+    result = pytester.runpytest("-h", f"--confcutdir={x}", x)
     result.stdout.fnmatch_lines(["*--xyz*"])
     result.stdout.no_fnmatch_line("*warning: could not load initial*")
 
@@ -380,7 +380,7 @@ def test_conftest_symlink_files(pytester: Pytester) -> None:
             """
         ),
     }
-    pytester.makepyfile(**{"real/%s" % k: v for k, v in source.items()})
+    pytester.makepyfile(**{f"real/{k}": v for k, v in source.items()})
 
     # Create a build directory that contains symlinks to actual files
     # but doesn't symlink actual directories.
@@ -402,7 +402,7 @@ def test_conftest_badcase(pytester: Pytester) -> None:
     """Check conftest.py loading when directory casing is wrong (#5792)."""
     pytester.path.joinpath("JenkinsRoot/test").mkdir(parents=True)
     source = {"setup.py": "", "test/__init__.py": "", "test/conftest.py": ""}
-    pytester.makepyfile(**{"JenkinsRoot/%s" % k: v for k, v in source.items()})
+    pytester.makepyfile(**{f"JenkinsRoot/{k}": v for k, v in source.items()})
 
     os.chdir(pytester.path.joinpath("jenkinsroot/test"))
     result = pytester.runpytest()
@@ -638,9 +638,9 @@ class TestConftestVisibility:
     ) -> None:
         """#616"""
         dirs = self._setup_tree(pytester)
-        print("pytest run in cwd: %s" % (dirs[chdir].relative_to(pytester.path)))
+        print(f"pytest run in cwd: {dirs[chdir].relative_to(pytester.path)}")
-        print("pytestarg        : %s" % testarg)
+        print(f"pytestarg        : {testarg}")
-        print("expected pass    : %s" % expect_ntests_passed)
+        print(f"expected pass    : {expect_ntests_passed}")
         os.chdir(dirs[chdir])
         reprec = pytester.inline_run(
             testarg,
@@ -699,7 +699,7 @@ def test_search_conftest_up_to_inifile(
 
     args = [str(src)]
     if confcutdir:
-        args = ["--confcutdir=%s" % root.joinpath(confcutdir)]
+        args = [f"--confcutdir={root.joinpath(confcutdir)}"]
     result = pytester.runpytest(*args)
     match = ""
     if passed:

testing/test_debugging.py

@@ -221,7 +221,7 @@ class TestPDB:
                 pass
         """
         )
-        child = pytester.spawn_pytest("--pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--pdb {p1}")
         child.expect("captured stdout")
         child.expect("get rekt")
         child.expect("captured stderr")
@@ -246,7 +246,7 @@ class TestPDB:
                 assert False
         """
         )
-        child = pytester.spawn_pytest("--pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--pdb {p1}")
         child.expect("Pdb")
         output = child.before.decode("utf8")
         child.sendeof()
@@ -283,7 +283,7 @@ class TestPDB:
                 assert False
         """
         )
-        child = pytester.spawn_pytest("--show-capture=all --pdb -p no:logging %s" % p1)
+        child = pytester.spawn_pytest(f"--show-capture=all --pdb -p no:logging {p1}")
         child.expect("get rekt")
         output = child.before.decode("utf8")
         assert "captured log" not in output
@@ -303,7 +303,7 @@ class TestPDB:
                 pytest.raises(ValueError, globalfunc)
         """
         )
-        child = pytester.spawn_pytest("--pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--pdb {p1}")
         child.expect(".*def test_1")
         child.expect(".*pytest.raises.*globalfunc")
         child.expect("Pdb")
@@ -320,7 +320,7 @@ class TestPDB:
             xxx
         """
         )
-        child = pytester.spawn_pytest("--pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--pdb {p1}")
         # child.expect(".*import pytest.*")
         child.expect("Pdb")
         child.sendline("c")
@@ -335,7 +335,7 @@ class TestPDB:
         """
         )
         p1 = pytester.makepyfile("def test_func(): pass")
-        child = pytester.spawn_pytest("--pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--pdb {p1}")
         child.expect("Pdb")
 
         # INTERNALERROR is only displayed once via terminal reporter.
@@ -461,7 +461,7 @@ class TestPDB:
                 assert 0
         """
         )
-        child = pytester.spawn_pytest("--pdb %s" % str(p1))
+        child = pytester.spawn_pytest(f"--pdb {p1!s}")
         child.send("caplog.record_tuples\n")
         child.expect_exact(
             "[('test_pdb_with_caplog_on_pdb_invocation', 30, 'some_warning')]"
@@ -501,7 +501,7 @@ class TestPDB:
                 '''
         """
         )
-        child = pytester.spawn_pytest("--doctest-modules --pdb %s" % p1)
+        child = pytester.spawn_pytest(f"--doctest-modules --pdb {p1}")
         child.expect("Pdb")
 
         assert "UNEXPECTED EXCEPTION: AssertionError()" in child.before.decode("utf8")
@@ -528,7 +528,7 @@ class TestPDB:
         )
         # NOTE: does not use pytest.set_trace, but Python's patched pdb,
         #       therefore "-s" is required.
-        child = pytester.spawn_pytest("--doctest-modules --pdb -s %s" % p1)
+        child = pytester.spawn_pytest(f"--doctest-modules --pdb -s {p1}")
         child.expect("Pdb")
         child.sendline("q")
         rest = child.read().decode("utf8")
@@ -621,7 +621,7 @@ class TestPDB:
                 pytest.fail("expected_failure")
         """
         )
-        child = pytester.spawn_pytest("--pdbcls=mytest:CustomPdb %s" % str(p1))
+        child = pytester.spawn_pytest(f"--pdbcls=mytest:CustomPdb {p1!s}")
         child.expect(r"PDB set_trace \(IO-capturing turned off\)")
         child.expect(r"\n\(Pdb")
         child.sendline("debug foo()")
@@ -658,7 +658,7 @@ class TestPDB:
                 pytest.set_trace()
         """
         )
-        child = pytester.spawn_pytest("-s %s" % p1)
+        child = pytester.spawn_pytest(f"-s {p1}")
         child.expect(r">>> PDB set_trace >>>")
         child.expect("Pdb")
         child.sendline("c")
@@ -914,7 +914,7 @@ class TestPDB:
         """
         )
         monkeypatch.setenv("PYTHONPATH", str(pytester.path))
-        child = pytester.spawn_pytest("--pdbcls=custom_pdb:CustomPdb %s" % str(p1))
+        child = pytester.spawn_pytest(f"--pdbcls=custom_pdb:CustomPdb {p1!s}")
 
         child.expect("__init__")
         child.expect("custom set_trace>")
@@ -1208,8 +1208,7 @@ def test_pdb_suspends_fixture_capturing(pytester: Pytester, fixture: str) -> Non
     child.expect("Pdb")
     before = child.before.decode("utf8")
     assert (
-        "> PDB set_trace (IO-capturing turned off for fixture %s) >" % (fixture)
+        f"> PDB set_trace (IO-capturing turned off for fixture {fixture}) >" in before
-        in before
     )
 
     # Test that capturing is really suspended.
@@ -1225,7 +1224,7 @@ def test_pdb_suspends_fixture_capturing(pytester: Pytester, fixture: str) -> Non
     TestPDB.flush(child)
     assert child.exitstatus == 0
     assert "= 1 passed in" in rest
-    assert "> PDB continue (IO-capturing resumed for fixture %s) >" % (fixture) in rest
+    assert f"> PDB continue (IO-capturing resumed for fixture {fixture}) >" in rest
 
 
 def test_pdbcls_via_local_module(pytester: Pytester) -> None:

testing/test_doctest.py

@@ -1160,7 +1160,7 @@ class TestDoctestSkips:
                 pytester.maketxtfile(doctest)
             else:
                 assert mode == "module"
-                pytester.makepyfile('"""\n%s"""' % doctest)
+                pytester.makepyfile(f'"""\n{doctest}"""')
 
         return makeit
 

testing/test_faulthandler.py

@@ -101,7 +101,7 @@ def test_timeout(pytester: Pytester, enabled: bool) -> None:
     result = pytester.runpytest_subprocess(*args)
     tb_output = "most recent call first"
     if enabled:
-        result.stderr.fnmatch_lines(["*%s*" % tb_output])
+        result.stderr.fnmatch_lines([f"*{tb_output}*"])
     else:
         assert tb_output not in result.stderr.str()
     result.stdout.fnmatch_lines(["*1 passed*"])

testing/test_junitxml.py

@@ -44,7 +44,7 @@ class RunAndParse:
         if family:
             args = ("-o", "junit_family=" + family, *args)
         xml_path = self.pytester.path.joinpath("junit.xml")
-        result = self.pytester.runpytest("--junitxml=%s" % xml_path, *args)
+        result = self.pytester.runpytest(f"--junitxml={xml_path}", *args)
         if family == "xunit2":
             with xml_path.open(encoding="utf-8") as f:
                 self.schema.validate(f)
@@ -520,7 +520,7 @@ class TestPython:
         )
 
         result, dom = run_and_parse(
-            "-o", "junit_logging=%s" % junit_logging, family=xunit_family
+            "-o", f"junit_logging={junit_logging}", family=xunit_family
         )
         assert result.ret, "Expected ret > 0"
         node = dom.find_first_by_tag("testsuite")
@@ -605,11 +605,11 @@ class TestPython:
         for index, char in enumerate("<&'"):
             tnode = node.find_nth_by_tag("testcase", index)
             tnode.assert_attr(
-                classname="test_failure_escape", name="test_func[%s]" % char
+                classname="test_failure_escape", name=f"test_func[{char}]"
             )
             sysout = tnode.find_first_by_tag("system-out")
             text = sysout.text
-            assert "%s\n" % char in text
+            assert f"{char}\n" in text
 
     @parametrize_families
     def test_junit_prefixing(
@@ -694,7 +694,7 @@ class TestPython:
                 assert 0
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         tnode = node.find_first_by_tag("testcase")
         if junit_logging in ["system-err", "out-err", "all"]:
@@ -764,13 +764,12 @@ class TestPython:
     def test_unicode(self, pytester: Pytester, run_and_parse: RunAndParse) -> None:
         value = "hx\xc4\x85\xc4\x87\n"
         pytester.makepyfile(
-            """\
+            f"""\
             # coding: latin1
             def test_hello():
-                print(%r)
+                print({value!r})
                 assert 0
             """
-            % value
         )
         result, dom = run_and_parse()
         assert result.ret == 1
@@ -805,7 +804,7 @@ class TestPython:
                 print('hello-stdout')
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         pnode = node.find_first_by_tag("testcase")
         if junit_logging == "no":
@@ -829,7 +828,7 @@ class TestPython:
                 sys.stderr.write('hello-stderr')
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         pnode = node.find_first_by_tag("testcase")
         if junit_logging == "no":
@@ -858,7 +857,7 @@ class TestPython:
                 pass
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         pnode = node.find_first_by_tag("testcase")
         if junit_logging == "no":
@@ -888,7 +887,7 @@ class TestPython:
                 pass
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         pnode = node.find_first_by_tag("testcase")
         if junit_logging == "no":
@@ -919,7 +918,7 @@ class TestPython:
                 sys.stdout.write('hello-stdout call')
         """
         )
-        result, dom = run_and_parse("-o", "junit_logging=%s" % junit_logging)
+        result, dom = run_and_parse("-o", f"junit_logging={junit_logging}")
         node = dom.find_first_by_tag("testsuite")
         pnode = node.find_first_by_tag("testcase")
         if junit_logging == "no":
@@ -1013,7 +1012,7 @@ def test_nullbyte(pytester: Pytester, junit_logging: str) -> None:
     """
     )
     xmlf = pytester.path.joinpath("junit.xml")
-    pytester.runpytest("--junitxml=%s" % xmlf, "-o", "junit_logging=%s" % junit_logging)
+    pytester.runpytest(f"--junitxml={xmlf}", "-o", f"junit_logging={junit_logging}")
     text = xmlf.read_text(encoding="utf-8")
     assert "\x00" not in text
     if junit_logging == "system-out":
@@ -1035,7 +1034,7 @@ def test_nullbyte_replace(pytester: Pytester, junit_logging: str) -> None:
     """
     )
     xmlf = pytester.path.joinpath("junit.xml")
-    pytester.runpytest("--junitxml=%s" % xmlf, "-o", "junit_logging=%s" % junit_logging)
+    pytester.runpytest(f"--junitxml={xmlf}", "-o", f"junit_logging={junit_logging}")
     text = xmlf.read_text(encoding="utf-8")
     if junit_logging == "system-out":
         assert "#x0" in text
@@ -1071,9 +1070,9 @@ def test_invalid_xml_escape() -> None:
     for i in invalid:
         got = bin_xml_escape(chr(i))
         if i <= 0xFF:
-            expected = "#x%02X" % i
+            expected = f"#x{i:02X}"
         else:
-            expected = "#x%04X" % i
+            expected = f"#x{i:04X}"
         assert got == expected
     for i in valid:
         assert chr(i) == bin_xml_escape(chr(i))
@@ -1748,7 +1747,7 @@ def test_logging_passing_tests_disabled_logs_output_for_failing_test_issue5430(
     """
     )
     result, dom = run_and_parse(
-        "-o", "junit_logging=%s" % junit_logging, family=xunit_family
+        "-o", f"junit_logging={junit_logging}", family=xunit_family
     )
     assert result.ret == 1
     node = dom.find_first_by_tag("testcase")

testing/test_legacypath.py

@@ -79,7 +79,7 @@ def test_tmpdir_always_is_realpath(pytester: pytest.Pytester) -> None:
             assert os.path.realpath(str(tmpdir)) == str(tmpdir)
     """
     )
-    result = pytester.runpytest("-s", p, "--basetemp=%s/bt" % linktemp)
+    result = pytester.runpytest("-s", p, f"--basetemp={linktemp}/bt")
     assert not result.ret
 
 

testing/test_monkeypatch.py

@@ -442,7 +442,7 @@ def test_syspath_prepend_with_namespace_packages(
         lib = ns.joinpath(dirname)
         lib.mkdir()
         lib.joinpath("__init__.py").write_text(
-            "def check(): return %r" % dirname, encoding="utf-8"
+            f"def check(): return {dirname!r}", encoding="utf-8"
         )
 
     monkeypatch.syspath_prepend("hello")

testing/test_pastebin.py

@@ -171,7 +171,7 @@ class TestPaste:
         assert type(data) is bytes
         lexer = "text"
         assert url == "https://bpa.st"
-        assert "lexer=%s" % lexer in data.decode()
+        assert f"lexer={lexer}" in data.decode()
         assert "code=full-paste-contents" in data.decode()
         assert "expiry=1week" in data.decode()
 

testing/test_skipping.py

@@ -297,13 +297,12 @@ class TestXFail:
     @pytest.mark.parametrize("strict", [True, False])
     def test_xfail_simple(self, pytester: Pytester, strict: bool) -> None:
         item = pytester.getitem(
-            """
+            f"""
             import pytest
-            @pytest.mark.xfail(strict=%s)
+            @pytest.mark.xfail(strict={strict})
             def test_func():
                 assert 0
         """
-            % strict
         )
         reports = runtestprotocol(item, log=False)
         assert len(reports) == 3
@@ -630,15 +629,14 @@ class TestXFail:
     @pytest.mark.parametrize("strict", [True, False])
     def test_strict_xfail(self, pytester: Pytester, strict: bool) -> None:
         p = pytester.makepyfile(
-            """
+            f"""
             import pytest
 
-            @pytest.mark.xfail(reason='unsupported feature', strict=%s)
+            @pytest.mark.xfail(reason='unsupported feature', strict={strict})
             def test_foo():
                 with open('foo_executed', 'w', encoding='utf-8'):
                     pass  # make sure test executes
         """
-            % strict
         )
         result = pytester.runpytest(p, "-rxX")
         if strict:
@@ -658,14 +656,13 @@ class TestXFail:
     @pytest.mark.parametrize("strict", [True, False])
     def test_strict_xfail_condition(self, pytester: Pytester, strict: bool) -> None:
         p = pytester.makepyfile(
-            """
+            f"""
             import pytest
 
-            @pytest.mark.xfail(False, reason='unsupported feature', strict=%s)
+            @pytest.mark.xfail(False, reason='unsupported feature', strict={strict})
             def test_foo():
                 pass
         """
-            % strict
         )
         result = pytester.runpytest(p, "-rxX")
         result.stdout.fnmatch_lines(["*1 passed*"])
@@ -674,14 +671,13 @@ class TestXFail:
     @pytest.mark.parametrize("strict", [True, False])
     def test_xfail_condition_keyword(self, pytester: Pytester, strict: bool) -> None:
         p = pytester.makepyfile(
-            """
+            f"""
             import pytest
 
-            @pytest.mark.xfail(condition=False, reason='unsupported feature', strict=%s)
+            @pytest.mark.xfail(condition=False, reason='unsupported feature', strict={strict})
             def test_foo():
                 pass
         """
-            % strict
         )
         result = pytester.runpytest(p, "-rxX")
         result.stdout.fnmatch_lines(["*1 passed*"])
@@ -692,11 +688,10 @@ class TestXFail:
         self, pytester: Pytester, strict_val
     ) -> None:
         pytester.makeini(
-            """
+            f"""
             [pytest]
-            xfail_strict = %s
+            xfail_strict = {strict_val}
         """
-            % strict_val
         )
         p = pytester.makepyfile(
             """

testing/test_terminal.py

@@ -1421,7 +1421,7 @@ def test_tbstyle_short(pytester: Pytester) -> None:
     s = result.stdout.str()
     assert "arg = 42" not in s
     assert "x = 0" not in s
-    result.stdout.fnmatch_lines(["*%s:8*" % p.name, "    assert x", "E   assert*"])
+    result.stdout.fnmatch_lines([f"*{p.name}:8*", "    assert x", "E   assert*"])
     result = pytester.runpytest()
     s = result.stdout.str()
     assert "x = 0" in s
@@ -1497,8 +1497,8 @@ class TestGenericReporting:
         """
         )
         for tbopt in ["long", "short", "no"]:
-            print("testing --tb=%s..." % tbopt)
+            print(f"testing --tb={tbopt}...")
-            result = pytester.runpytest("-rN", "--tb=%s" % tbopt)
+            result = pytester.runpytest("-rN", f"--tb={tbopt}")
             s = result.stdout.str()
             if tbopt == "long":
                 assert "print(6*7)" in s
@@ -1528,7 +1528,7 @@ class TestGenericReporting:
         result = pytester.runpytest("--tb=line")
         bn = p.name
         result.stdout.fnmatch_lines(
-            ["*%s:3: IndexError*" % bn, "*%s:8: AssertionError: hello*" % bn]
+            [f"*{bn}:3: IndexError*", f"*{bn}:8: AssertionError: hello*"]
         )
         s = result.stdout.str()
         assert "def test_func2" not in s
@@ -1544,7 +1544,7 @@ class TestGenericReporting:
         result = pytester.runpytest("--tb=line")
         result.stdout.str()
         bn = p.name
-        result.stdout.fnmatch_lines(["*%s:3: Failed: test_func1" % bn])
+        result.stdout.fnmatch_lines([f"*{bn}:3: Failed: test_func1"])
 
     def test_pytest_report_header(self, pytester: Pytester, option) -> None:
         pytester.makeconftest(
@@ -1945,7 +1945,7 @@ def test_summary_stats(
     # Reset cache.
     tr._main_color = None
 
-    print("Based on stats: %s" % stats_arg)
+    print(f"Based on stats: {stats_arg}")
     print(f'Expect summary: "{exp_line}"; with color "{exp_color}"')
     (line, color) = tr.build_summary_stats_line()
     print(f'Actually got:   "{line}"; with color "{color}"')

testing/test_tmpdir.py

@@ -87,11 +87,11 @@ class TestConfigTmpPath:
                 pass
         """
         )
-        pytester.runpytest(p, "--basetemp=%s" % mytemp)
+        pytester.runpytest(p, f"--basetemp={mytemp}")
         assert mytemp.exists()
         mytemp.joinpath("hello").touch()
 
-        pytester.runpytest(p, "--basetemp=%s" % mytemp)
+        pytester.runpytest(p, f"--basetemp={mytemp}")
         assert mytemp.exists()
         assert not mytemp.joinpath("hello").exists()
 
@@ -248,7 +248,7 @@ def test_mktemp(pytester: Pytester, basename: str, is_ok: bool) -> None:
         """
     )
 
-    result = pytester.runpytest(p, "--basetemp=%s" % mytemp)
+    result = pytester.runpytest(p, f"--basetemp={mytemp}")
     if is_ok:
         assert result.ret == 0
         assert mytemp.joinpath(basename).exists()

testing/test_warnings.py

@@ -44,7 +44,7 @@ def test_normal_flow(pytester: Pytester, pyfile_with_warnings) -> None:
     result = pytester.runpytest(pyfile_with_warnings)
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "test_normal_flow.py::test_func",
             "*normal_flow_module.py:3: UserWarning: user warning",
             '*  warnings.warn(UserWarning("user warning"))',
@@ -75,7 +75,7 @@ def test_setup_teardown_warnings(pytester: Pytester) -> None:
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "*test_setup_teardown_warnings.py:6: UserWarning: warning during setup",
             '*warnings.warn(UserWarning("warning during setup"))',
             "*test_setup_teardown_warnings.py:8: UserWarning: warning during teardown",
@@ -143,7 +143,7 @@ def test_unicode(pytester: Pytester) -> None:
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "*test_unicode.py:7: UserWarning: \u6d4b\u8bd5*",
             "* 1 passed, 1 warning*",
         ]
@@ -315,7 +315,7 @@ def test_collection_warnings(pytester: Pytester) -> None:
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "  *collection_warnings.py:3: UserWarning: collection warning",
             '    warnings.warn(UserWarning("collection warning"))',
             "* 1 passed, 1 warning*",
@@ -374,7 +374,7 @@ def test_hide_pytest_internal_warnings(
     else:
         result.stdout.fnmatch_lines(
             [
-                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+                f"*== {WARNINGS_SUMMARY_HEADER} ==*",
                 "*test_hide_pytest_internal_warnings.py:4: PytestWarning: some internal warning",
                 "* 1 passed, 1 warning *",
             ]
@@ -461,7 +461,7 @@ class TestDeprecationWarningsByDefault:
         result = pytester.runpytest_subprocess()
         result.stdout.fnmatch_lines(
             [
-                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+                f"*== {WARNINGS_SUMMARY_HEADER} ==*",
                 "*test_shown_by_default.py:3: DeprecationWarning: collection",
                 "*test_shown_by_default.py:7: PendingDeprecationWarning: test run",
                 "* 1 passed, 2 warnings*",
@@ -492,7 +492,7 @@ class TestDeprecationWarningsByDefault:
         result = pytester.runpytest_subprocess()
         result.stdout.fnmatch_lines(
             [
-                "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+                f"*== {WARNINGS_SUMMARY_HEADER} ==*",
                 "*test_hidden_by_mark.py:3: DeprecationWarning: collection",
                 "* 1 passed, 1 warning*",
             ]
@@ -555,7 +555,7 @@ def test_removed_in_x_warning_as_error(pytester: Pytester, change_default) -> No
 class TestAssertionWarnings:
     @staticmethod
     def assert_result_warns(result, msg) -> None:
-        result.stdout.fnmatch_lines(["*PytestAssertRewriteWarning: %s*" % msg])
+        result.stdout.fnmatch_lines([f"*PytestAssertRewriteWarning: {msg}*"])
 
     def test_tuple_warning(self, pytester: Pytester) -> None:
         pytester.makepyfile(
@@ -585,7 +585,7 @@ def test_group_warnings_by_message(pytester: Pytester) -> None:
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "test_group_warnings_by_message.py::test_foo[[]0[]]",
             "test_group_warnings_by_message.py::test_foo[[]1[]]",
             "test_group_warnings_by_message.py::test_foo[[]2[]]",
@@ -617,7 +617,7 @@ def test_group_warnings_by_message_summary(pytester: Pytester) -> None:
     result = pytester.runpytest()
     result.stdout.fnmatch_lines(
         [
-            "*== %s ==*" % WARNINGS_SUMMARY_HEADER,
+            f"*== {WARNINGS_SUMMARY_HEADER} ==*",
             "test_1.py: 21 warnings",
             "test_2.py: 1 warning",
             "  */test_1.py:8: UserWarning: foo",