diff --git a/src/_pytest/junitxml.py b/src/_pytest/junitxml.py
index 8ecc13a8c..1e563eb8d 100644
--- a/src/_pytest/junitxml.py
+++ b/src/_pytest/junitxml.py
@@ -25,6 +25,7 @@ from _pytest import deprecated
 from _pytest import nodes
 from _pytest import timing
 from _pytest._code.code import ExceptionRepr
+from _pytest._code.code import ReprFileLocation
 from _pytest.config import Config
 from _pytest.config import filename_arg
 from _pytest.config.argparsing import Parser
@@ -200,8 +201,11 @@ class _NodeReporter:
             self._add_simple("skipped", "xfail-marked test passes unexpectedly")
         else:
             assert report.longrepr is not None
-            if getattr(report.longrepr, "reprcrash", None) is not None:
-                message = report.longrepr.reprcrash.message
+            reprcrash = getattr(
+                report.longrepr, "reprcrash", None
+            )  # type: Optional[ReprFileLocation]
+            if reprcrash is not None:
+                message = reprcrash.message
             else:
                 message = str(report.longrepr)
             message = bin_xml_escape(message)
@@ -217,8 +221,11 @@ class _NodeReporter:
 
     def append_error(self, report: TestReport) -> None:
         assert report.longrepr is not None
-        if getattr(report.longrepr, "reprcrash", None) is not None:
-            reason = report.longrepr.reprcrash.message
+        reprcrash = getattr(
+            report.longrepr, "reprcrash", None
+        )  # type: Optional[ReprFileLocation]
+        if reprcrash is not None:
+            reason = reprcrash.message
         else:
             reason = str(report.longrepr)
 
@@ -237,7 +244,7 @@ class _NodeReporter:
             skipped = ET.Element("skipped", type="pytest.xfail", message=xfailreason)
             self.append(skipped)
         else:
-            assert report.longrepr is not None
+            assert isinstance(report.longrepr, tuple)
             filename, lineno, skipreason = report.longrepr
             if skipreason.startswith("Skipped: "):
                 skipreason = skipreason[9:]
diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index e0e7b1fbc..83c525fd8 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -28,6 +28,7 @@ import pytest
 from _pytest import timing
 from _pytest._code import Source
 from _pytest.capture import _get_multicapture
+from _pytest.compat import overload
 from _pytest.compat import TYPE_CHECKING
 from _pytest.config import _PluggyPlugin
 from _pytest.config import Config
@@ -42,11 +43,13 @@ from _pytest.nodes import Item
 from _pytest.pathlib import make_numbered_dir
 from _pytest.pathlib import Path
 from _pytest.python import Module
+from _pytest.reports import CollectReport
 from _pytest.reports import TestReport
 from _pytest.tmpdir import TempdirFactory
 
 if TYPE_CHECKING:
     from typing import Type
+    from typing_extensions import Literal
 
     import pexpect
 
@@ -180,24 +183,24 @@ class PytestArg:
         return hookrecorder
 
 
-def get_public_names(values):
+def get_public_names(values: Iterable[str]) -> List[str]:
     """Only return names from iterator values without a leading underscore."""
     return [x for x in values if x[0] != "_"]
 
 
 class ParsedCall:
-    def __init__(self, name, kwargs):
+    def __init__(self, name: str, kwargs) -> None:
         self.__dict__.update(kwargs)
         self._name = name
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         d = self.__dict__.copy()
         del d["_name"]
         return "<ParsedCall {!r}(**{!r})>".format(self._name, d)
 
     if TYPE_CHECKING:
         # The class has undetermined attributes, this tells mypy about it.
-        def __getattr__(self, key):
+        def __getattr__(self, key: str):
             raise NotImplementedError()
 
 
@@ -211,6 +214,7 @@ class HookRecorder:
     def __init__(self, pluginmanager: PytestPluginManager) -> None:
         self._pluginmanager = pluginmanager
         self.calls = []  # type: List[ParsedCall]
+        self.ret = None  # type: Optional[Union[int, ExitCode]]
 
         def before(hook_name: str, hook_impls, kwargs) -> None:
             self.calls.append(ParsedCall(hook_name, kwargs))
@@ -228,7 +232,7 @@ class HookRecorder:
             names = names.split()
         return [call for call in self.calls if call._name in names]
 
-    def assert_contains(self, entries) -> None:
+    def assert_contains(self, entries: Sequence[Tuple[str, str]]) -> None:
         __tracebackhide__ = True
         i = 0
         entries = list(entries)
@@ -266,22 +270,46 @@ class HookRecorder:
 
     # functionality for test reports
 
+    @overload
     def getreports(
+        self, names: "Literal['pytest_collectreport']",
+    ) -> Sequence[CollectReport]:
+        raise NotImplementedError()
+
+    @overload  # noqa: F811
+    def getreports(  # noqa: F811
+        self, names: "Literal['pytest_runtest_logreport']",
+    ) -> Sequence[TestReport]:
+        raise NotImplementedError()
+
+    @overload  # noqa: F811
+    def getreports(  # noqa: F811
         self,
-        names: Union[
-            str, Iterable[str]
-        ] = "pytest_runtest_logreport pytest_collectreport",
-    ) -> List[TestReport]:
+        names: Union[str, Iterable[str]] = (
+            "pytest_collectreport",
+            "pytest_runtest_logreport",
+        ),
+    ) -> Sequence[Union[CollectReport, TestReport]]:
+        raise NotImplementedError()
+
+    def getreports(  # noqa: F811
+        self,
+        names: Union[str, Iterable[str]] = (
+            "pytest_collectreport",
+            "pytest_runtest_logreport",
+        ),
+    ) -> Sequence[Union[CollectReport, TestReport]]:
         return [x.report for x in self.getcalls(names)]
 
     def matchreport(
         self,
         inamepart: str = "",
-        names: Union[
-            str, Iterable[str]
-        ] = "pytest_runtest_logreport pytest_collectreport",
-        when=None,
-    ):
+        names: Union[str, Iterable[str]] = (
+            "pytest_runtest_logreport",
+            "pytest_collectreport",
+        ),
+        when: Optional[str] = None,
+    ) -> Union[CollectReport, TestReport]:
         """Return a testreport whose dotted import path matches."""
         values = []
         for rep in self.getreports(names=names):
@@ -305,26 +333,56 @@ class HookRecorder:
             )
         return values[0]
 
+    @overload
     def getfailures(
+        self, names: "Literal['pytest_collectreport']",
+    ) -> Sequence[CollectReport]:
+        raise NotImplementedError()
+
+    @overload  # noqa: F811
+    def getfailures(  # noqa: F811
+        self, names: "Literal['pytest_runtest_logreport']",
+    ) -> Sequence[TestReport]:
+        raise NotImplementedError()
+
+    @overload  # noqa: F811
+    def getfailures(  # noqa: F811
         self,
-        names: Union[
-            str, Iterable[str]
-        ] = "pytest_runtest_logreport pytest_collectreport",
-    ) -> List[TestReport]:
+        names: Union[str, Iterable[str]] = (
+            "pytest_collectreport",
+            "pytest_runtest_logreport",
+        ),
+    ) -> Sequence[Union[CollectReport, TestReport]]:
+        raise NotImplementedError()
+
+    def getfailures(  # noqa: F811
+        self,
+        names: Union[str, Iterable[str]] = (
+            "pytest_collectreport",
+            "pytest_runtest_logreport",
+        ),
+    ) -> Sequence[Union[CollectReport, TestReport]]:
         return [rep for rep in self.getreports(names) if rep.failed]
 
-    def getfailedcollections(self) -> List[TestReport]:
+    def getfailedcollections(self) -> Sequence[CollectReport]:
         return self.getfailures("pytest_collectreport")
 
     def listoutcomes(
         self,
-    ) -> Tuple[List[TestReport], List[TestReport], List[TestReport]]:
+    ) -> Tuple[
+        Sequence[TestReport],
+        Sequence[Union[CollectReport, TestReport]],
+        Sequence[Union[CollectReport, TestReport]],
+    ]:
         passed = []
         skipped = []
         failed = []
-        for rep in self.getreports("pytest_collectreport pytest_runtest_logreport"):
+        for rep in self.getreports(
+            ("pytest_collectreport", "pytest_runtest_logreport")
+        ):
             if rep.passed:
                 if rep.when == "call":
+                    assert isinstance(rep, TestReport)
                     passed.append(rep)
             elif rep.skipped:
                 skipped.append(rep)
@@ -879,7 +937,7 @@ class Testdir:
         runner = testclassinstance.getrunner()
         return runner(item)
 
-    def inline_runsource(self, source, *cmdlineargs):
+    def inline_runsource(self, source, *cmdlineargs) -> HookRecorder:
         """Run a test module in process using ``pytest.main()``.
 
         This run writes "source" into a temporary file and runs
@@ -896,7 +954,7 @@ class Testdir:
         values = list(cmdlineargs) + [p]
         return self.inline_run(*values)
 
-    def inline_genitems(self, *args):
+    def inline_genitems(self, *args) -> Tuple[List[Item], HookRecorder]:
         """Run ``pytest.main(['--collectonly'])`` in-process.
 
         Runs the :py:func:`pytest.main` function to run all of pytest inside
@@ -907,7 +965,9 @@ class Testdir:
         items = [x.item for x in rec.getcalls("pytest_itemcollected")]
         return items, rec
 
-    def inline_run(self, *args, plugins=(), no_reraise_ctrlc: bool = False):
+    def inline_run(
+        self, *args, plugins=(), no_reraise_ctrlc: bool = False
+    ) -> HookRecorder:
         """Run ``pytest.main()`` in-process, returning a HookRecorder.
 
         Runs the :py:func:`pytest.main` function to run all of pytest inside
@@ -962,7 +1022,7 @@ class Testdir:
                 class reprec:  # type: ignore
                     pass
 
-            reprec.ret = ret  # type: ignore[attr-defined]
+            reprec.ret = ret
 
             # Typically we reraise keyboard interrupts from the child run
             # because it's our user requesting interruption of the testing.
@@ -1010,6 +1070,7 @@ class Testdir:
             sys.stdout.write(out)
             sys.stderr.write(err)
 
+        assert reprec.ret is not None
         res = RunResult(
             reprec.ret, out.splitlines(), err.splitlines(), timing.time() - now
         )
diff --git a/src/_pytest/reports.py b/src/_pytest/reports.py
index 707972fcf..305379863 100644
--- a/src/_pytest/reports.py
+++ b/src/_pytest/reports.py
@@ -1,6 +1,7 @@
 from io import StringIO
 from pprint import pprint
 from typing import Any
+from typing import cast
 from typing import Dict
 from typing import Iterable
 from typing import Iterator
@@ -15,6 +16,7 @@ import py
 
 from _pytest._code.code import ExceptionChainRepr
 from _pytest._code.code import ExceptionInfo
+from _pytest._code.code import ExceptionRepr
 from _pytest._code.code import ReprEntry
 from _pytest._code.code import ReprEntryNative
 from _pytest._code.code import ReprExceptionInfo
@@ -57,8 +59,9 @@ _R = TypeVar("_R", bound="BaseReport")
 class BaseReport:
     when = None  # type: Optional[str]
     location = None  # type: Optional[Tuple[str, Optional[int], str]]
-    # TODO: Improve this Any.
-    longrepr = None  # type: Optional[Any]
+    longrepr = (
+        None
+    )  # type: Union[None, ExceptionInfo[BaseException], Tuple[str, int, str], str, TerminalRepr]
     sections = []  # type: List[Tuple[str, str]]
     nodeid = None  # type: str
 
@@ -79,7 +82,8 @@ class BaseReport:
             return
 
         if hasattr(longrepr, "toterminal"):
-            longrepr.toterminal(out)
+            longrepr_terminal = cast(TerminalRepr, longrepr)
+            longrepr_terminal.toterminal(out)
         else:
             try:
                 s = str(longrepr)
@@ -233,7 +237,9 @@ class TestReport(BaseReport):
         location: Tuple[str, Optional[int], str],
         keywords,
         outcome: "Literal['passed', 'failed', 'skipped']",
-        longrepr,
+        longrepr: Union[
+            None, ExceptionInfo[BaseException], Tuple[str, int, str], str, TerminalRepr
+        ],
         when: "Literal['setup', 'call', 'teardown']",
         sections: Iterable[Tuple[str, str]] = (),
         duration: float = 0,
@@ -293,8 +299,9 @@ class TestReport(BaseReport):
         sections = []
         if not call.excinfo:
             outcome = "passed"  # type: Literal["passed", "failed", "skipped"]
-            # TODO: Improve this Any.
-            longrepr = None  # type: Optional[Any]
+            longrepr = (
+                None
+            )  # type: Union[None, ExceptionInfo[BaseException], Tuple[str, int, str], str, TerminalRepr]
         else:
             if not isinstance(excinfo, ExceptionInfo):
                 outcome = "failed"
@@ -372,7 +379,7 @@ class CollectReport(BaseReport):
 
 
 class CollectErrorRepr(TerminalRepr):
-    def __init__(self, msg) -> None:
+    def __init__(self, msg: str) -> None:
         self.longrepr = msg
 
     def toterminal(self, out: TerminalWriter) -> None:
@@ -436,16 +443,18 @@ def _report_to_json(report: BaseReport) -> Dict[str, Any]:
         else:
             return None
 
-    def serialize_longrepr(rep: BaseReport) -> Dict[str, Any]:
+    def serialize_exception_longrepr(rep: BaseReport) -> Dict[str, Any]:
         assert rep.longrepr is not None
+        # TODO: Investigate whether the duck typing is really necessary here.
+        longrepr = cast(ExceptionRepr, rep.longrepr)
         result = {
-            "reprcrash": serialize_repr_crash(rep.longrepr.reprcrash),
-            "reprtraceback": serialize_repr_traceback(rep.longrepr.reprtraceback),
-            "sections": rep.longrepr.sections,
+            "reprcrash": serialize_repr_crash(longrepr.reprcrash),
+            "reprtraceback": serialize_repr_traceback(longrepr.reprtraceback),
+            "sections": longrepr.sections,
         }  # type: Dict[str, Any]
-        if isinstance(rep.longrepr, ExceptionChainRepr):
+        if isinstance(longrepr, ExceptionChainRepr):
             result["chain"] = []
-            for repr_traceback, repr_crash, description in rep.longrepr.chain:
+            for repr_traceback, repr_crash, description in longrepr.chain:
                 result["chain"].append(
                     (
                         serialize_repr_traceback(repr_traceback),
@@ -462,7 +471,7 @@ def _report_to_json(report: BaseReport) -> Dict[str, Any]:
         if hasattr(report.longrepr, "reprtraceback") and hasattr(
             report.longrepr, "reprcrash"
         ):
-            d["longrepr"] = serialize_longrepr(report)
+            d["longrepr"] = serialize_exception_longrepr(report)
         else:
             d["longrepr"] = str(report.longrepr)
     else:
diff --git a/src/_pytest/resultlog.py b/src/_pytest/resultlog.py
index 356a39c12..c043c749f 100644
--- a/src/_pytest/resultlog.py
+++ b/src/_pytest/resultlog.py
@@ -1,5 +1,7 @@
 """log machine-parseable test session result information to a plain text file."""
 import os
+from typing import IO
+from typing import Union
 
 import py
 
@@ -52,16 +54,18 @@ def pytest_unconfigure(config: Config) -> None:
 
 
 class ResultLog:
-    def __init__(self, config, logfile):
+    def __init__(self, config: Config, logfile: IO[str]) -> None:
         self.config = config
         self.logfile = logfile  # preferably line buffered
 
-    def write_log_entry(self, testpath, lettercode, longrepr):
+    def write_log_entry(self, testpath: str, lettercode: str, longrepr: str) -> None:
         print("{} {}".format(lettercode, testpath), file=self.logfile)
         for line in longrepr.splitlines():
             print(" %s" % line, file=self.logfile)
 
-    def log_outcome(self, report, lettercode, longrepr):
+    def log_outcome(
+        self, report: Union[TestReport, CollectReport], lettercode: str, longrepr: str
+    ) -> None:
         testpath = getattr(report, "nodeid", None)
         if testpath is None:
             testpath = report.fspath
@@ -73,7 +77,7 @@ class ResultLog:
         res = self.config.hook.pytest_report_teststatus(
             report=report, config=self.config
         )
-        code = res[1]
+        code = res[1]  # type: str
         if code == "x":
             longrepr = str(report.longrepr)
         elif code == "X":
@@ -81,7 +85,7 @@ class ResultLog:
         elif report.passed:
             longrepr = ""
         elif report.skipped:
-            assert report.longrepr is not None
+            assert isinstance(report.longrepr, tuple)
             longrepr = str(report.longrepr[2])
         else:
             longrepr = str(report.longrepr)
diff --git a/src/_pytest/runner.py b/src/_pytest/runner.py
index 4923406b9..4089fc689 100644
--- a/src/_pytest/runner.py
+++ b/src/_pytest/runner.py
@@ -2,7 +2,6 @@
 import bdb
 import os
 import sys
-from typing import Any
 from typing import Callable
 from typing import cast
 from typing import Dict
@@ -22,6 +21,7 @@ from .reports import TestReport
 from _pytest import timing
 from _pytest._code.code import ExceptionChainRepr
 from _pytest._code.code import ExceptionInfo
+from _pytest._code.code import TerminalRepr
 from _pytest.compat import TYPE_CHECKING
 from _pytest.config.argparsing import Parser
 from _pytest.nodes import Collector
@@ -327,8 +327,7 @@ def pytest_runtest_makereport(item: Item, call: CallInfo[None]) -> TestReport:
 
 def pytest_make_collect_report(collector: Collector) -> CollectReport:
     call = CallInfo.from_call(lambda: list(collector.collect()), "collect")
-    # TODO: Better typing for longrepr.
-    longrepr = None  # type: Optional[Any]
+    longrepr = None  # type: Union[None, Tuple[str, int, str], str, TerminalRepr]
     if not call.excinfo:
         outcome = "passed"  # type: Literal["passed", "skipped", "failed"]
     else:
@@ -348,6 +347,7 @@ def pytest_make_collect_report(collector: Collector) -> CollectReport:
             outcome = "failed"
             errorinfo = collector.repr_failure(call.excinfo)
             if not hasattr(errorinfo, "toterminal"):
+                assert isinstance(errorinfo, str)
                 errorinfo = CollectErrorRepr(errorinfo)
             longrepr = errorinfo
     result = call.result if not call.excinfo else None
diff --git a/src/_pytest/terminal.py b/src/_pytest/terminal.py
index e6ba293e6..1d49df4cf 100644
--- a/src/_pytest/terminal.py
+++ b/src/_pytest/terminal.py
@@ -1247,6 +1247,7 @@ def _folded_skips(
     d = {}  # type: Dict[Tuple[str, Optional[int], str], List[CollectReport]]
     for event in skipped:
         assert event.longrepr is not None
+        assert isinstance(event.longrepr, tuple), (event, event.longrepr)
         assert len(event.longrepr) == 3, (event, event.longrepr)
         fspath, lineno, reason = event.longrepr
         # For consistency, report all fspaths in relative form.
diff --git a/testing/test_reports.py b/testing/test_reports.py
index a47d53787..dbe948962 100644
--- a/testing/test_reports.py
+++ b/testing/test_reports.py
@@ -1,14 +1,19 @@
 import sys
+from typing import Sequence
+from typing import Union
 
 import pytest
 from _pytest._code.code import ExceptionChainRepr
+from _pytest._code.code import ExceptionRepr
+from _pytest.config import Config
 from _pytest.pathlib import Path
+from _pytest.pytester import Testdir
 from _pytest.reports import CollectReport
 from _pytest.reports import TestReport
 
 
 class TestReportSerialization:
-    def test_xdist_longrepr_to_str_issue_241(self, testdir):
+    def test_xdist_longrepr_to_str_issue_241(self, testdir: Testdir) -> None:
         """Regarding issue pytest-xdist#241.
 
         This test came originally from test_remote.py in xdist (ca03269).
@@ -31,7 +36,7 @@ class TestReportSerialization:
         assert test_b_call.outcome == "passed"
         assert test_b_call._to_json()["longrepr"] is None
 
-    def test_xdist_report_longrepr_reprcrash_130(self, testdir) -> None:
+    def test_xdist_report_longrepr_reprcrash_130(self, testdir: Testdir) -> None:
         """Regarding issue pytest-xdist#130
 
         This test came originally from test_remote.py in xdist (ca03269).
@@ -46,15 +51,18 @@ class TestReportSerialization:
         assert len(reports) == 3
         rep = reports[1]
         added_section = ("Failure Metadata", "metadata metadata", "*")
+        assert isinstance(rep.longrepr, ExceptionRepr)
         rep.longrepr.sections.append(added_section)
         d = rep._to_json()
         a = TestReport._from_json(d)
-        assert a.longrepr is not None
+        assert isinstance(a.longrepr, ExceptionRepr)
         # Check assembled == rep
         assert a.__dict__.keys() == rep.__dict__.keys()
         for key in rep.__dict__.keys():
             if key != "longrepr":
                 assert getattr(a, key) == getattr(rep, key)
+        assert rep.longrepr.reprcrash is not None
+        assert a.longrepr.reprcrash is not None
         assert rep.longrepr.reprcrash.lineno == a.longrepr.reprcrash.lineno
         assert rep.longrepr.reprcrash.message == a.longrepr.reprcrash.message
         assert rep.longrepr.reprcrash.path == a.longrepr.reprcrash.path
@@ -67,7 +75,7 @@ class TestReportSerialization:
         # Missing section attribute PR171
         assert added_section in a.longrepr.sections
 
-    def test_reprentries_serialization_170(self, testdir) -> None:
+    def test_reprentries_serialization_170(self, testdir: Testdir) -> None:
         """Regarding issue pytest-xdist#170
 
         This test came originally from test_remote.py in xdist (ca03269).
@@ -85,25 +93,35 @@ class TestReportSerialization:
         reports = reprec.getreports("pytest_runtest_logreport")
         assert len(reports) == 3
         rep = reports[1]
+        assert isinstance(rep.longrepr, ExceptionRepr)
         d = rep._to_json()
         a = TestReport._from_json(d)
-        assert a.longrepr is not None
+        assert isinstance(a.longrepr, ExceptionRepr)
 
         rep_entries = rep.longrepr.reprtraceback.reprentries
         a_entries = a.longrepr.reprtraceback.reprentries
         for i in range(len(a_entries)):
-            assert isinstance(rep_entries[i], ReprEntry)
-            assert rep_entries[i].lines == a_entries[i].lines
-            assert rep_entries[i].reprfileloc.lineno == a_entries[i].reprfileloc.lineno
-            assert (
-                rep_entries[i].reprfileloc.message == a_entries[i].reprfileloc.message
-            )
-            assert rep_entries[i].reprfileloc.path == a_entries[i].reprfileloc.path
-            assert rep_entries[i].reprfuncargs.args == a_entries[i].reprfuncargs.args
-            assert rep_entries[i].reprlocals.lines == a_entries[i].reprlocals.lines
-            assert rep_entries[i].style == a_entries[i].style
+            rep_entry = rep_entries[i]
+            assert isinstance(rep_entry, ReprEntry)
+            assert rep_entry.reprfileloc is not None
+            assert rep_entry.reprfuncargs is not None
+            assert rep_entry.reprlocals is not None
 
-    def test_reprentries_serialization_196(self, testdir) -> None:
+            a_entry = a_entries[i]
+            assert isinstance(a_entry, ReprEntry)
+            assert a_entry.reprfileloc is not None
+            assert a_entry.reprfuncargs is not None
+            assert a_entry.reprlocals is not None
+
+            assert rep_entry.lines == a_entry.lines
+            assert rep_entry.reprfileloc.lineno == a_entry.reprfileloc.lineno
+            assert rep_entry.reprfileloc.message == a_entry.reprfileloc.message
+            assert rep_entry.reprfileloc.path == a_entry.reprfileloc.path
+            assert rep_entry.reprfuncargs.args == a_entry.reprfuncargs.args
+            assert rep_entry.reprlocals.lines == a_entry.reprlocals.lines
+            assert rep_entry.style == a_entry.style
+
+    def test_reprentries_serialization_196(self, testdir: Testdir) -> None:
         """Regarding issue pytest-xdist#196
 
         This test came originally from test_remote.py in xdist (ca03269).
@@ -121,9 +139,10 @@ class TestReportSerialization:
         reports = reprec.getreports("pytest_runtest_logreport")
         assert len(reports) == 3
         rep = reports[1]
+        assert isinstance(rep.longrepr, ExceptionRepr)
         d = rep._to_json()
         a = TestReport._from_json(d)
-        assert a.longrepr is not None
+        assert isinstance(a.longrepr, ExceptionRepr)
 
         rep_entries = rep.longrepr.reprtraceback.reprentries
         a_entries = a.longrepr.reprtraceback.reprentries
@@ -131,7 +150,7 @@ class TestReportSerialization:
             assert isinstance(rep_entries[i], ReprEntryNative)
             assert rep_entries[i].lines == a_entries[i].lines
 
-    def test_itemreport_outcomes(self, testdir):
+    def test_itemreport_outcomes(self, testdir: Testdir) -> None:
         # This test came originally from test_remote.py in xdist (ca03269).
         reprec = testdir.inline_runsource(
             """
@@ -157,7 +176,7 @@ class TestReportSerialization:
             assert newrep.failed == rep.failed
             assert newrep.skipped == rep.skipped
             if newrep.skipped and not hasattr(newrep, "wasxfail"):
-                assert newrep.longrepr is not None
+                assert isinstance(newrep.longrepr, tuple)
                 assert len(newrep.longrepr) == 3
             assert newrep.outcome == rep.outcome
             assert newrep.when == rep.when
@@ -165,7 +184,7 @@ class TestReportSerialization:
             if rep.failed:
                 assert newrep.longreprtext == rep.longreprtext
 
-    def test_collectreport_passed(self, testdir):
+    def test_collectreport_passed(self, testdir: Testdir) -> None:
         """This test came originally from test_remote.py in xdist (ca03269)."""
         reprec = testdir.inline_runsource("def test_func(): pass")
         reports = reprec.getreports("pytest_collectreport")
@@ -176,7 +195,7 @@ class TestReportSerialization:
             assert newrep.failed == rep.failed
             assert newrep.skipped == rep.skipped
 
-    def test_collectreport_fail(self, testdir):
+    def test_collectreport_fail(self, testdir: Testdir) -> None:
         """This test came originally from test_remote.py in xdist (ca03269)."""
         reprec = testdir.inline_runsource("qwe abc")
         reports = reprec.getreports("pytest_collectreport")
@@ -190,13 +209,13 @@ class TestReportSerialization:
             if rep.failed:
                 assert newrep.longrepr == str(rep.longrepr)
 
-    def test_extended_report_deserialization(self, testdir):
+    def test_extended_report_deserialization(self, testdir: Testdir) -> None:
         """This test came originally from test_remote.py in xdist (ca03269)."""
         reprec = testdir.inline_runsource("qwe abc")
         reports = reprec.getreports("pytest_collectreport")
         assert reports
         for rep in reports:
-            rep.extra = True
+            rep.extra = True  # type: ignore[attr-defined]
             d = rep._to_json()
             newrep = CollectReport._from_json(d)
             assert newrep.extra
@@ -206,7 +225,7 @@ class TestReportSerialization:
             if rep.failed:
                 assert newrep.longrepr == str(rep.longrepr)
 
-    def test_paths_support(self, testdir):
+    def test_paths_support(self, testdir: Testdir) -> None:
         """Report attributes which are py.path or pathlib objects should become strings."""
         testdir.makepyfile(
             """
@@ -218,13 +237,13 @@ class TestReportSerialization:
         reports = reprec.getreports("pytest_runtest_logreport")
         assert len(reports) == 3
         test_a_call = reports[1]
-        test_a_call.path1 = testdir.tmpdir
-        test_a_call.path2 = Path(testdir.tmpdir)
+        test_a_call.path1 = testdir.tmpdir  # type: ignore[attr-defined]
+        test_a_call.path2 = Path(testdir.tmpdir)  # type: ignore[attr-defined]
         data = test_a_call._to_json()
         assert data["path1"] == str(testdir.tmpdir)
         assert data["path2"] == str(testdir.tmpdir)
 
-    def test_deserialization_failure(self, testdir):
+    def test_deserialization_failure(self, testdir: Testdir) -> None:
         """Check handling of failure during deserialization of report types."""
         testdir.makepyfile(
             """
@@ -247,7 +266,7 @@ class TestReportSerialization:
             TestReport._from_json(data)
 
     @pytest.mark.parametrize("report_class", [TestReport, CollectReport])
-    def test_chained_exceptions(self, testdir, tw_mock, report_class):
+    def test_chained_exceptions(self, testdir: Testdir, tw_mock, report_class) -> None:
         """Check serialization/deserialization of report objects containing chained exceptions (#5786)"""
         testdir.makepyfile(
             """
@@ -267,7 +286,9 @@ class TestReportSerialization:
 
         reprec = testdir.inline_run()
         if report_class is TestReport:
-            reports = reprec.getreports("pytest_runtest_logreport")
+            reports = reprec.getreports(
+                "pytest_runtest_logreport"
+            )  # type: Union[Sequence[TestReport], Sequence[CollectReport]]
             # we have 3 reports: setup/call/teardown
             assert len(reports) == 3
             # get the call report
@@ -279,7 +300,7 @@ class TestReportSerialization:
             assert len(reports) == 2
             report = reports[1]
 
-        def check_longrepr(longrepr):
+        def check_longrepr(longrepr: ExceptionChainRepr) -> None:
             """Check the attributes of the given longrepr object according to the test file.
 
             We can get away with testing both CollectReport and TestReport with this function because
@@ -303,6 +324,7 @@ class TestReportSerialization:
 
         assert report.failed
         assert len(report.sections) == 0
+        assert isinstance(report.longrepr, ExceptionChainRepr)
         report.longrepr.addsection("title", "contents", "=")
         check_longrepr(report.longrepr)
 
@@ -317,7 +339,7 @@ class TestReportSerialization:
         # elsewhere and we do check the contents of the longrepr object after loading it.
         loaded_report.longrepr.toterminal(tw_mock)
 
-    def test_chained_exceptions_no_reprcrash(self, testdir, tw_mock) -> None:
+    def test_chained_exceptions_no_reprcrash(self, testdir: Testdir, tw_mock) -> None:
         """Regression test for tracebacks without a reprcrash (#5971)
 
         This happens notably on exceptions raised by multiprocess.pool: the exception transfer
@@ -368,7 +390,7 @@ class TestReportSerialization:
 
         reports = reprec.getreports("pytest_runtest_logreport")
 
-        def check_longrepr(longrepr) -> None:
+        def check_longrepr(longrepr: object) -> None:
             assert isinstance(longrepr, ExceptionChainRepr)
             assert len(longrepr.chain) == 2
             entry1, entry2 = longrepr.chain
@@ -397,9 +419,12 @@ class TestReportSerialization:
 
         # for same reasons as previous test, ensure we don't blow up here
         assert loaded_report.longrepr is not None
+        assert isinstance(loaded_report.longrepr, ExceptionChainRepr)
         loaded_report.longrepr.toterminal(tw_mock)
 
-    def test_report_prevent_ConftestImportFailure_hiding_exception(self, testdir):
+    def test_report_prevent_ConftestImportFailure_hiding_exception(
+        self, testdir: Testdir
+    ) -> None:
         sub_dir = testdir.tmpdir.join("ns").ensure_dir()
         sub_dir.join("conftest").new(ext=".py").write("import unknown")
 
@@ -411,7 +436,7 @@ class TestReportSerialization:
 class TestHooks:
     """Test that the hooks are working correctly for plugins"""
 
-    def test_test_report(self, testdir, pytestconfig):
+    def test_test_report(self, testdir: Testdir, pytestconfig: Config) -> None:
         testdir.makepyfile(
             """
             def test_a(): assert False
@@ -433,7 +458,7 @@ class TestHooks:
             assert new_rep.when == rep.when
             assert new_rep.outcome == rep.outcome
 
-    def test_collect_report(self, testdir, pytestconfig):
+    def test_collect_report(self, testdir: Testdir, pytestconfig: Config) -> None:
         testdir.makepyfile(
             """
             def test_a(): assert False
@@ -458,7 +483,9 @@ class TestHooks:
     @pytest.mark.parametrize(
         "hook_name", ["pytest_runtest_logreport", "pytest_collectreport"]
     )
-    def test_invalid_report_types(self, testdir, pytestconfig, hook_name):
+    def test_invalid_report_types(
+        self, testdir: Testdir, pytestconfig: Config, hook_name: str
+    ) -> None:
         testdir.makepyfile(
             """
             def test_a(): pass
diff --git a/testing/test_resultlog.py b/testing/test_resultlog.py
index 8fc93d25c..f2eb612c1 100644
--- a/testing/test_resultlog.py
+++ b/testing/test_resultlog.py
@@ -1,18 +1,21 @@
 import os
 from io import StringIO
+from typing import List
 
 import _pytest._code
 import pytest
+from _pytest.pytester import Testdir
 from _pytest.resultlog import pytest_configure
 from _pytest.resultlog import pytest_unconfigure
 from _pytest.resultlog import ResultLog
 from _pytest.resultlog import resultlog_key
 
+
 pytestmark = pytest.mark.filterwarnings("ignore:--result-log is deprecated")
 
 
-def test_write_log_entry():
-    reslog = ResultLog(None, None)
+def test_write_log_entry() -> None:
+    reslog = ResultLog(None, None)  # type: ignore[arg-type]
     reslog.logfile = StringIO()
     reslog.write_log_entry("name", ".", "")
     entry = reslog.logfile.getvalue()
@@ -54,14 +57,14 @@ class TestWithFunctionIntegration:
     # XXX (hpk) i think that the resultlog plugin should
     # provide a Parser object so that one can remain
     # ignorant regarding formatting details.
-    def getresultlog(self, testdir, arg):
+    def getresultlog(self, testdir: Testdir, arg: str) -> List[str]:
         resultlog = testdir.tmpdir.join("resultlog")
         testdir.plugins.append("resultlog")
         args = ["--resultlog=%s" % resultlog] + [arg]
         testdir.runpytest(*args)
         return [x for x in resultlog.readlines(cr=0) if x]
 
-    def test_collection_report(self, testdir):
+    def test_collection_report(self, testdir: Testdir) -> None:
         ok = testdir.makepyfile(test_collection_ok="")
         fail = testdir.makepyfile(test_collection_fail="XXX")
         lines = self.getresultlog(testdir, ok)
@@ -75,7 +78,7 @@ class TestWithFunctionIntegration:
             assert x.startswith(" ")
         assert "XXX" in "".join(lines[1:])
 
-    def test_log_test_outcomes(self, testdir):
+    def test_log_test_outcomes(self, testdir: Testdir) -> None:
         mod = testdir.makepyfile(
             test_mod="""
             import pytest
@@ -111,16 +114,17 @@ class TestWithFunctionIntegration:
         assert len(lines) == 15
 
     @pytest.mark.parametrize("style", ("native", "long", "short"))
-    def test_internal_exception(self, style):
+    def test_internal_exception(self, style) -> None:
         # they are produced for example by a teardown failing
         # at the end of the run or a failing hook invocation
         try:
             raise ValueError
         except ValueError:
             excinfo = _pytest._code.ExceptionInfo.from_current()
-        reslog = ResultLog(None, StringIO())
+        file = StringIO()
+        reslog = ResultLog(None, file)  # type: ignore[arg-type]
         reslog.pytest_internalerror(excinfo.getrepr(style=style))
-        entry = reslog.logfile.getvalue()
+        entry = file.getvalue()
         entry_lines = entry.splitlines()
 
         assert entry_lines[0].startswith("! ")
@@ -130,7 +134,7 @@ class TestWithFunctionIntegration:
         assert "ValueError" in entry
 
 
-def test_generic(testdir, LineMatcher):
+def test_generic(testdir: Testdir, LineMatcher) -> None:
     testdir.plugins.append("resultlog")
     testdir.makepyfile(
         """
@@ -162,7 +166,7 @@ def test_generic(testdir, LineMatcher):
     )
 
 
-def test_makedir_for_resultlog(testdir, LineMatcher):
+def test_makedir_for_resultlog(testdir: Testdir, LineMatcher) -> None:
     """--resultlog should automatically create directories for the log file"""
     testdir.plugins.append("resultlog")
     testdir.makepyfile(
@@ -177,7 +181,7 @@ def test_makedir_for_resultlog(testdir, LineMatcher):
     LineMatcher(lines).fnmatch_lines([". *:test_pass"])
 
 
-def test_no_resultlog_on_workers(testdir):
+def test_no_resultlog_on_workers(testdir: Testdir) -> None:
     config = testdir.parseconfig("-p", "resultlog", "--resultlog=resultlog")
 
     assert resultlog_key not in config._store
@@ -186,14 +190,14 @@ def test_no_resultlog_on_workers(testdir):
     pytest_unconfigure(config)
     assert resultlog_key not in config._store
 
-    config.workerinput = {}
+    config.workerinput = {}  # type: ignore[attr-defined]
     pytest_configure(config)
     assert resultlog_key not in config._store
     pytest_unconfigure(config)
     assert resultlog_key not in config._store
 
 
-def test_unknown_teststatus(testdir):
+def test_unknown_teststatus(testdir: Testdir) -> None:
     """Ensure resultlog correctly handles unknown status from pytest_report_teststatus
 
     Inspired on pytest-rerunfailures.
@@ -229,7 +233,7 @@ def test_unknown_teststatus(testdir):
     assert lines[0] == "r test_unknown_teststatus.py::test"
 
 
-def test_failure_issue380(testdir):
+def test_failure_issue380(testdir: Testdir) -> None:
     testdir.makeconftest(
         """
         import pytest