test: we don't need two sys.path restorers

tests/coveragetest.py

@@ -24,7 +24,7 @@
 
 from tests.helpers import arcs_to_arcz_repr, arcz_to_arcs, assert_count_equal
 from tests.helpers import nice_file, run_command
-from tests.mixins import PytestBase, StdStreamCapturingMixin, SysPathModulesMixin, TempDirMixin
+from tests.mixins import PytestBase, StdStreamCapturingMixin, RestoreModulesMixin, TempDirMixin
 
 
 # Status returns for the command line.
@@ -36,7 +36,7 @@
 
 class CoverageTest(
     StdStreamCapturingMixin,
-    SysPathModulesMixin,
+    RestoreModulesMixin,
     TempDirMixin,
     PytestBase,
 ):

tests/mixins.py

@@ -82,17 +82,8 @@ def make_file(self, filename, text="", bytes=b"", newline=None):
         return make_file(filename, text, bytes, newline)
 
 
-class SysPathModulesMixin:
-    """Auto-restore sys.path and the imported modules at the end of each test."""
-
-    @pytest.fixture(autouse=True)
-    def _save_sys_path(self):
-        """Restore sys.path at the end of each test."""
-        old_syspath = sys.path[:]
-        try:
-            yield
-        finally:
-            sys.path = old_syspath
+class RestoreModulesMixin:
+    """Auto-restore the imported modules at the end of each test."""
 
     @pytest.fixture(autouse=True)
     def _module_saving(self):

tests/test_mixins.py

@@ -7,7 +7,7 @@
 
 from coverage.misc import import_local_file
 
-from tests.mixins import TempDirMixin, SysPathModulesMixin
+from tests.mixins import TempDirMixin, RestoreModulesMixin
 
 
 class TempDirMixinTest(TempDirMixin):
@@ -59,7 +59,7 @@ def test_make_bytes_file(self):
         assert data == b"\x99\x33\x66hello\0"
 
 
-class SysPathModulessMixinTest(TempDirMixin, SysPathModulesMixin):
+class RestoreModulessMixinTest(TempDirMixin, RestoreModulesMixin):
     """Tests of SysPathModulesMixin."""
 
     @pytest.mark.parametrize("val", [17, 42])