1 files changed, 45 insertions, 0 deletions
diff --git a/wheel/test/conftest.py b/wheel/test/conftest.py
new file mode 100644
index 0000000..d14cc47
--- /dev/null
+++ b/wheel/test/conftest.py
@@ -0,0 +1,45 @@
+"""
+pytest local configuration plug-in
+"""
+
+import gc
+import warnings
+
+import pytest
+
+@pytest.yield_fixture(scope='function', autouse=True)
+def error_on_ResourceWarning():
+    """This fixture captures ResourceWarning's and reports an "error"
+    describing the file handles left open.
+    
+    This is shown regardless of how successful the test was, if a test fails
+    and leaves files open then those files will be reported.  Ideally, even
+    those files should be closed properly after a test failure or exception.
+
+    Since only Python 3 and PyPy3 have ResourceWarning's, this context will
+    have no effect when running tests on Python 2 or PyPy.
+
+    Because of autouse=True, this function will be automatically enabled for
+    all test_* functions in this module.
+
+    This code is primarily based on the examples found here:
+    https://stackoverflow.com/questions/24717027/convert-python-3-resourcewarnings-into-exception
+    """
+    try:
+        ResourceWarning
+    except NameError:
+        # Python 2, PyPy
+        yield
+        return
+    # Python 3, PyPy3
+    with warnings.catch_warnings(record=True) as caught:
+        warnings.resetwarnings() # clear all filters
+        warnings.simplefilter('ignore') # ignore all
+        warnings.simplefilter('always', ResourceWarning) # add filter
+        yield # run tests in this context
+        gc.collect() # run garbage collection (for pypy3)
+        if not caught:
+            return
+        pytest.fail('The following file descriptors were not closed properly:\n' +
+                    '\n'.join((str(warning.message) for warning in caught)),
+                    pytrace=False)