test(fix): isolate excepthook tests from each other

Author: nedbat

tests/test_execfile.py

@@ -10,6 +10,7 @@
 import pathlib
 import py_compile
 import re
+import sys
 
 import pytest
 
@@ -26,6 +27,12 @@
 class RunFileTest(CoverageTest):
     """Test cases for `run_python_file`."""
 
+    @pytest.fixture(autouse=True)
+    def clean_up(self):
+        """These tests all run in-process. Clean up global changes."""
+        yield
+        sys.excepthook = sys.__excepthook__
+
     def test_run_python_file(self):
         run_python_file([TRY_EXECFILE, "arg1", "arg2"])
         mod_globs = json.loads(self.stdout())

tests/test_process.py

@@ -1092,6 +1092,8 @@ def test_bug_909(self):
 class ExcepthookTest(CoverageTest):
     """Tests of sys.excepthook support."""
 
+    # TODO: do we need these as process tests if we have test_execfile.py:RunFileTest?
+
     def test_excepthook(self):
         self.make_file("excepthook.py", """\
             import sys