test both str and Path

tests/test_python.py

@@ -68,17 +68,19 @@ def test_source_for_file_windows(tmp_path: pathlib.Path) -> None:
 class RunpyTest(CoverageTest):
     """Tests using runpy."""
 
-    def test_runpy_path(self) -> None:
-        """Ensure runpy.run_path(path) works when path is pathlib.Path.
-
-        runpy.run_path(pathlib.Path(...)) causes __file__ to be a Path,
-        which may make source_for_file() stumble (#1819).
-        """
-
-        self.check_coverage("""\
+    @pytest.mark.parametrize("convert_to", ["str", "Path"])
+    def test_runpy_path(self, convert_to) -> None:
+        # Ensure runpy.run_path(path) works when path is pathlib.Path or str.
+        #
+        # runpy.run_path(pathlib.Path(...)) causes __file__ to be a Path,
+        # which may make source_for_file() stumble (#1819) with:
+        #
+        #    AttributeError: 'PosixPath' object has no attribute 'endswith'
+
+        self.check_coverage(f"""\
             import runpy
             from pathlib import Path
             pyfile = Path('script.py')
             pyfile.write_text('')
-            runpy.run_path(pyfile)
+            runpy.run_path({convert_to}(pyfile))
         """)