Move the decorator out of the metaclass, so we can test it

2 files changed, 36 insertions, 14 deletions

diff --git a/tests/coveragetest.py b/tests/coveragetest.py
index bd5cf9af..306df3b8 100644
--- a/tests/coveragetest.py
+++ b/tests/coveragetest.py
@@ -36,26 +36,27 @@ from tests.helpers import run_command
 OK, ERR = 0, 1
 
 
+def convert_skip_exceptions(method):
+    """A decorator for test methods to convert StopEverything to SkipTest."""
+    def wrapper(*args, **kwargs):
+        """Run the test method, and convert exceptions."""
+        try:
+            result = method(*args, **kwargs)
+        except StopEverything:
+            raise unittest.SkipTest("StopEverything!")
+        return result
+    return wrapper
+
+
 class SkipConvertingMetaclass(type):
     """Decorate all test methods to convert StopEverything to SkipTest."""
     def __new__(mcs, name, bases, attrs):
         for attr_name, attr_value in attrs.items():
             if attr_name.startswith('test_') and isinstance(attr_value, types.FunctionType):
-                attrs[attr_name] = mcs.convert_skip_exceptions(attr_value)
+                attrs[attr_name] = convert_skip_exceptions(attr_value)
 
         return super(SkipConvertingMetaclass, mcs).__new__(mcs, name, bases, attrs)
 
-    @classmethod
-    def convert_skip_exceptions(mcs, method):
-        """The decorator that wraps test methods."""
-        def wrapper(*args, **kwargs):
-            """Run the test method, and convert StopEverything to SkipTest."""
-            try:
-                result = method(*args, **kwargs)
-            except StopEverything:
-                raise unittest.SkipTest("StopEverything!")
-            return result
-        return wrapper
 
 CoverageTestMethodsMixin = SkipConvertingMetaclass('CoverageTestMethodsMixin', (), {})
 
diff --git a/tests/test_testing.py b/tests/test_testing.py
index a7f60b31..9776acb4 100644
--- a/tests/test_testing.py
+++ b/tests/test_testing.py
@@ -11,10 +11,11 @@ import sys
 import pytest
 
 import coverage
-from coverage.backunittest import TestCase
+from coverage.backunittest import TestCase, unittest
 from coverage.files import actual_path
+from coverage.misc import StopEverything
 
-from tests.coveragetest import CoverageTest
+from tests.coveragetest import CoverageTest, convert_skip_exceptions
 from tests.helpers import CheckUniqueFilenames, re_lines, re_line
 
 
@@ -203,6 +204,26 @@ def test_re_line_bad(text, pat):
         re_line(text, pat)
 
 
+def test_convert_skip_exceptions():
+    @convert_skip_exceptions
+    def some_method(ret=None, exc=None):
+        """Be like a test case."""
+        if exc:
+            raise exc("yikes!")
+        return ret
+
+    # Normal flow is normal.
+    assert some_method(ret=[17, 23]) == [17, 23]
+
+    # Exceptions are raised normally.
+    with pytest.raises(ValueError):
+        some_method(exc=ValueError)
+
+    # But a StopEverything becomes a SkipTest.
+    with pytest.raises(unittest.SkipTest):
+        some_method(exc=StopEverything)
+
+
 def _same_python_executable(e1, e2):
     """Determine if `e1` and `e2` refer to the same Python executable.