Improve summary stats when using '--collect-only' (#7875)

Co-authored-by: Bruno Oliveira <nicoddemus@gmail.com>

changelog/7701.improvement.rst

@@ -0,0 +1 @@
+Improved reporting when using ``--collected-only``. It will now show the number of collected tests in the summary stats.

doc/en/example/nonpython.rst

@@ -102,4 +102,4 @@ interesting to just look at the collection tree:
         <YamlItem hello>
         <YamlItem ok>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 2 tests found in 0.12s ===========================

doc/en/example/parametrize.rst

@@ -175,7 +175,7 @@ objects, they are still using the default pytest representation:
       <Function test_timedistance_v3[forward]>
       <Function test_timedistance_v3[backward]>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 8 tests found in 0.12s ===========================
 
 In ``test_timedistance_v3``, we used ``pytest.param`` to specify the test IDs
 together with the actual data, instead of listing them separately.
@@ -252,7 +252,7 @@ If you just collect tests you'll also nicely see 'advanced' and 'basic' as varia
           <Function test_demo1[advanced]>
           <Function test_demo2[advanced]>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 4 tests found in 0.12s ===========================
 
 Note that we told ``metafunc.parametrize()`` that your scenario values
 should be considered class-scoped.  With pytest-2.3 this leads to a
@@ -328,7 +328,7 @@ Let's first see how it looks like at collection time:
       <Function test_db_initialized[d1]>
       <Function test_db_initialized[d2]>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 2/2 tests found in 0.12s ===========================
 
 And then when we run the test:
 

doc/en/example/pythoncollection.rst

@@ -157,7 +157,7 @@ The test collection would look like this:
           <Function simple_check>
           <Function complex_check>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 2 tests found in 0.12s ===========================
 
 You can check for multiple glob patterns by adding a space between the patterns:
 
@@ -220,7 +220,7 @@ You can always peek at the collection tree without running tests like this:
           <Function test_method>
           <Function test_anothermethod>
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== 3 tests found in 0.12s ===========================
 
 .. _customizing-test-collection:
 
@@ -282,7 +282,7 @@ leave out the ``setup.py`` file:
     <Module 'pkg/module_py2.py'>
       <Function 'test_only_on_python2'>
 
-    ====== no tests ran in 0.04 seconds ======
+    ====== 1 tests found in 0.04 seconds ======
 
 If you run with a Python 3 interpreter both the one test and the ``setup.py``
 file will be left out:
@@ -296,7 +296,7 @@ file will be left out:
     rootdir: $REGENDOC_TMPDIR, configfile: pytest.ini
     collected 0 items
 
-    ========================== no tests ran in 0.12s ===========================
+    ========================== no tests found in 0.12s ===========================
 
 It's also possible to ignore files based on Unix shell-style wildcards by adding
 patterns to :globalvar:`collect_ignore_glob`.

doc/en/fixture.rst

@@ -919,7 +919,7 @@ Running the above tests results in the following test IDs being used:
      <Function test_ehlo[mail.python.org]>
      <Function test_noop[mail.python.org]>
 
-   ========================== no tests ran in 0.12s ===========================
+   ========================== 10 tests found in 0.12s ===========================
 
 .. _`fixture-parametrize-marks`:
 

src/_pytest/terminal.py

@@ -1163,15 +1163,45 @@ class TerminalReporter:
         self._main_color = self._determine_main_color(bool(unknown_types))
 
     def build_summary_stats_line(self) -> Tuple[List[Tuple[str, Dict[str, bool]]], str]:
-        main_color, known_types = self._get_main_color()
+        """
+        Build the parts used in the last summary stats line.
 
+        The summary stats line is the line shown at the end, "=== 12 passed, 2 errors in Xs===".
+
+        This function builds a list of the "parts" that make up for the text in that line, in
+        the example above it would be:
+
+            [
+                ("12 passed", {"green": True}),
+                ("2 errors", {"red": True}
+            ]
+
+        That last dict for each line is a "markup dictionary", used by TerminalWriter to
+        color output.
+
+        The final color of the line is also determined by this function, and is the second
+        element of the returned tuple.
+        """
+        if self.config.getoption("collectonly"):
+            return self._build_collect_only_summary_stats_line()
+        else:
+            return self._build_normal_summary_stats_line()
+
+    def _get_reports_to_display(self, key: str) -> List[Any]:
+        """Get test/collection reports for the given status key, such as `passed` or `error`."""
+        reports = self.stats.get(key, [])
+        return [x for x in reports if getattr(x, "count_towards_summary", True)]
+
+    def _build_normal_summary_stats_line(
+        self,
+    ) -> Tuple[List[Tuple[str, Dict[str, bool]]], str]:
+        main_color, known_types = self._get_main_color()
         parts = []
+
         for key in known_types:
-            reports = self.stats.get(key, None)
+            reports = self._get_reports_to_display(key)
             if reports:
-                count = sum(
-                    1 for rep in reports if getattr(rep, "count_towards_summary", True)
-                )
+                count = len(reports)
                 color = _color_for_type.get(key, _color_for_type_default)
                 markup = {color: True, "bold": color == main_color}
                 parts.append(("%d %s" % _make_plural(count, key), markup))
@@ -1181,6 +1211,40 @@ class TerminalReporter:
 
         return parts, main_color
 
+    def _build_collect_only_summary_stats_line(
+        self,
+    ) -> Tuple[List[Tuple[str, Dict[str, bool]]], str]:
+        deselected = len(self._get_reports_to_display("deselected"))
+        errors = len(self._get_reports_to_display("error"))
+
+        if self._numcollected == 0:
+            parts = [("no tests collected", {"yellow": True})]
+            main_color = "yellow"
+
+        elif deselected == 0:
+            main_color = "green"
+            collected_output = "%d %s collected" % _make_plural(
+                self._numcollected, "test"
+            )
+            parts = [(collected_output, {main_color: True})]
+        else:
+            all_tests_were_deselected = self._numcollected == deselected
+            if all_tests_were_deselected:
+                main_color = "yellow"
+                collected_output = f"no tests collected ({deselected} deselected)"
+            else:
+                main_color = "green"
+                selected = self._numcollected - deselected
+                collected_output = f"{selected}/{self._numcollected} tests collected ({deselected} deselected)"
+
+            parts = [(collected_output, {main_color: True})]
+
+        if errors:
+            main_color = _color_for_type["error"]
+            parts += [("%d %s" % _make_plural(errors, "error"), {main_color: True})]
+
+        return parts, main_color
+
 
 def _get_pos(config: Config, rep: BaseReport):
     nodeid = config.cwd_relative_nodeid(rep.nodeid)
@@ -1267,7 +1331,7 @@ _color_for_type_default = "yellow"
 
 def _make_plural(count: int, noun: str) -> Tuple[int, str]:
     # No need to pluralize words such as `failed` or `passed`.
-    if noun not in ["error", "warnings"]:
+    if noun not in ["error", "warnings", "test"]:
         return count, noun
 
     # The `warnings` key is plural. To avoid API breakage, we keep it that way but

testing/logging/test_reporting.py

@@ -889,7 +889,7 @@ def test_collection_collect_only_live_logging(testdir, verbose):
             [
                 "*collected 1 item*",
                 "*<Module test_collection_collect_only_live_logging.py>*",
-                "*no tests ran*",
+                "*1 test collected*",
             ]
         )
     elif verbose == "-q":
@@ -897,7 +897,7 @@ def test_collection_collect_only_live_logging(testdir, verbose):
         expected_lines.extend(
             [
                 "*test_collection_collect_only_live_logging.py::test_simple*",
-                "no tests ran in [0-9].[0-9][0-9]s",
+                "1 test collected in [0-9].[0-9][0-9]s",
             ]
         )
     elif verbose == "-qq":

testing/python/metafunc.py

@@ -1417,7 +1417,7 @@ class TestMetafuncFunctional:
                 '    @pytest.mark.parametrise("x", range(2))',
                 "E   Failed: Unknown 'parametrise' mark, did you mean 'parametrize'?",
                 "*! Interrupted: 1 error during collection !*",
-                "*= 1 error in *",
+                "*= no tests collected, 1 error in *",
             ]
         )
 

testing/test_cacheprovider.py

@@ -909,7 +909,7 @@ class TestLastFailed:
                 "",
                 "<Module pkg1/test_1.py>",
                 "  <Function test_fail>",
-                "*= 1 deselected in *",
+                "*= 1/2 tests collected (1 deselected) in *",
             ],
         )
 
@@ -942,7 +942,7 @@ class TestLastFailed:
                 "      <Function test_fail>",
                 "  <Function test_other>",
                 "",
-                "*= 1 deselected in *",
+                "*= 2/3 tests collected (1 deselected) in *",
             ],
             consecutive=True,
         )
@@ -977,7 +977,7 @@ class TestLastFailed:
                 "<Module pkg1/test_1.py>",
                 "  <Function test_pass>",
                 "",
-                "*= no tests ran in*",
+                "*= 1 test collected in*",
             ],
             consecutive=True,
         )

testing/test_terminal.py

@@ -458,6 +458,48 @@ class TestCollectonly:
         result = testdir.runpytest("--collect-only", "-qq")
         result.stdout.fnmatch_lines(["*test_fun.py: 1*"])
 
+    def test_collect_only_summary_status(self, testdir):
+        """Custom status depending on test selection using -k or -m. #7701."""
+        testdir.makepyfile(
+            test_collect_foo="""
+            def test_foo(): pass
+            """,
+            test_collect_bar="""
+            def test_foobar(): pass
+            def test_bar(): pass
+            """,
+        )
+        result = testdir.runpytest("--collect-only")
+        result.stdout.fnmatch_lines("*== 3 tests collected in * ==*")
+
+        result = testdir.runpytest("--collect-only", "test_collect_foo.py")
+        result.stdout.fnmatch_lines("*== 1 test collected in * ==*")
+
+        result = testdir.runpytest("--collect-only", "-k", "foo")
+        result.stdout.fnmatch_lines("*== 2/3 tests collected (1 deselected) in * ==*")
+
+        result = testdir.runpytest("--collect-only", "-k", "test_bar")
+        result.stdout.fnmatch_lines("*== 1/3 tests collected (2 deselected) in * ==*")
+
+        result = testdir.runpytest("--collect-only", "-k", "invalid")
+        result.stdout.fnmatch_lines("*== no tests collected (3 deselected) in * ==*")
+
+        testdir.mkdir("no_tests_here")
+        result = testdir.runpytest("--collect-only", "no_tests_here")
+        result.stdout.fnmatch_lines("*== no tests collected in * ==*")
+
+        testdir.makepyfile(
+            test_contains_error="""
+            raise RuntimeError
+            """,
+        )
+        result = testdir.runpytest("--collect-only")
+        result.stdout.fnmatch_lines("*== 3 tests collected, 1 error in * ==*")
+        result = testdir.runpytest("--collect-only", "-k", "foo")
+        result.stdout.fnmatch_lines(
+            "*== 2/3 tests collected (1 deselected), 1 error in * ==*"
+        )
+
 
 class TestFixtureReporting:
     def test_setup_fixture_error(self, testdir):