Epic bug: pyexpat fiddles incorrectly with the systrace function. This is a hack to make it behave correctly with coverage.py. Fixes bug #10.

1 files changed, 46 insertions, 1 deletions

diff --git a/test/test_coverage.py b/test/test_coverage.py
index 30ac4b8c..2d08281f 100644
--- a/test/test_coverage.py
+++ b/test/test_coverage.py
@@ -1704,6 +1704,51 @@ class RecursionTest(CoverageTest):
             [1,2,3,5,7], "")
 
 
+class PyexpatTest(CoverageTest):
+    """Pyexpat screws up tracing. Make sure we've counter-defended properly."""
+    def testPyexpat(self):
+        # pyexpat calls the trace function explicitly (inexplicably), and does
+        # it wrong for exceptions.  Parsing a DOCTYPE for some reason throws
+        # an exception internally, and triggers its wrong behavior.  This test
+        # checks that our fake PyTrace_RETURN hack in tracer.c works.  It will
+        # also detect if the pyexpat bug is fixed unbeknownst to us, meaning
+        # we'd see two RETURNs where there should only be one.
+
+        self.makeFile("trydom.py", """\
+            import xml.dom.minidom
+
+            XML = '''\\
+            <!DOCTYPE fooey SYSTEM "http://www.example.com/example.dtd">
+            <root><child/><child/></root>
+            '''
+
+            def foo():
+                dom = xml.dom.minidom.parseString(XML)
+                assert len(dom.getElementsByTagName('child')) == 2
+                print "Parsed"
+
+            foo()
+            """)
+
+        self.makeFile("outer.py", "\n"*100 + "import trydom\nprint 'done'\n")
+
+        cov = coverage.coverage()
+        cov.erase()
+
+        # Import the python file, executing it.
+        cov.start()
+        self.importModule("outer")
+        cov.stop()
+
+        _, statements, missing, _ = cov.analysis("trydom.py")
+        self.assertEqual(statements, [1,3,8,9,10,11,13])
+        self.assertEqual(missing, [])
+    
+        _, statements, missing, _ = cov.analysis("outer.py")
+        self.assertEqual(statements, [101,102])
+        self.assertEqual(missing, [])
+
+
 if __name__ == '__main__':
     print "Testing under Python version: %s" % sys.version
     unittest.main()
@@ -1714,4 +1759,4 @@ if __name__ == '__main__':
 #         in an expression!)
 # TODO: Generator comprehensions? 
 # TODO: Constant if tests ("if 1:").  Py 2.4 doesn't execute them.
-# TODO: There are no tests for analysis2 directly.
\ No newline at end of file
+# TODO: There are no tests for analysis2 directly.