refactor(test): a context manager to swallow warnings

4 files changed, 24 insertions, 5 deletions

diff --git a/tests/conftest.py b/tests/conftest.py
index 16999d96..39f39e25 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -45,6 +45,11 @@ def set_warnings():
         message=r".*imp module is deprecated in favour of importlib",
         )
 
+    warnings.filterwarnings(
+        "ignore",
+        category=pytest.PytestRemovedIn8Warning,
+        )
+
     if env.PYPY:
         # pypy3 warns about unclosed files a lot.
         warnings.filterwarnings("ignore", r".*unclosed file", category=ResourceWarning)
diff --git a/tests/helpers.py b/tests/helpers.py
index 29464d1c..890bd7c5 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -12,6 +12,7 @@ import re
 import shutil
 import subprocess
 import textwrap
+import warnings
 
 from unittest import mock
 
@@ -308,3 +309,14 @@ def assert_coverage_warnings(warns, *msgs):
             assert expected.search(actual), f"{actual!r} didn't match {expected!r}"
         else:
             assert expected == actual
+
+
+@contextlib.contextmanager
+def swallow_warnings(message=r".", category=CoverageWarning):
+    """Swallow particular warnings.
+
+    It's OK if they happen, or if they don't happen. Just ignore them.
+    """
+    with warnings.catch_warnings():
+        warnings.filterwarnings("ignore", category=category, message=message)
+        yield
diff --git a/tests/test_oddball.py b/tests/test_oddball.py
index e2c17517..9536c121 100644
--- a/tests/test_oddball.py
+++ b/tests/test_oddball.py
@@ -16,6 +16,7 @@ from coverage.files import abs_file
 from coverage.misc import import_local_file
 
 from tests.coveragetest import CoverageTest
+from tests.helpers import swallow_warnings
 from tests import osinfo
 
 
@@ -82,7 +83,7 @@ class RecursionTest(CoverageTest):
     def test_long_recursion(self):
         # We can't finish a very deep recursion, but we don't crash.
         with pytest.raises(RuntimeError):
-            with pytest.warns(None):
+            with swallow_warnings("Trace function changed, measurement is likely wrong: None"):
                 self.check_coverage("""\
                     def recur(n):
                         if n == 0:
@@ -119,7 +120,7 @@ class RecursionTest(CoverageTest):
             """)
 
         cov = coverage.Coverage()
-        with pytest.warns(None):
+        with swallow_warnings("Trace function changed, measurement is likely wrong: None"):
             self.start_import_stop(cov, "recur")
 
         pytrace = (cov._collector.tracer_name() == "PyTracer")
diff --git a/tests/test_plugins.py b/tests/test_plugins.py
index 45b3bc9e..edf849f6 100644
--- a/tests/test_plugins.py
+++ b/tests/test_plugins.py
@@ -21,7 +21,7 @@ from coverage.misc import import_local_file
 import coverage.plugin
 
 from tests.coveragetest import CoverageTest
-from tests.helpers import CheckUniqueFilenames
+from tests.helpers import CheckUniqueFilenames, swallow_warnings
 
 
 class FakeConfig:
@@ -194,8 +194,9 @@ class PluginTest(CoverageTest):
         cov = coverage.Coverage(debug=["sys"])
         cov._debug_file = debug_out
         cov.set_option("run:plugins", ["plugin_sys_info"])
-        with pytest.warns(None):
-            # Catch warnings so we don't see "plugins aren't supported on PyTracer"
+        with swallow_warnings(
+            r"Plugin file tracers \(plugin_sys_info.Plugin\) aren't supported with PyTracer"
+            ):
             cov.start()
         cov.stop()      # pragma: nested