Merge pull request #57 from hydralabs/xml-module-tests

Rewrite xml tests to better support third party libs

Author: njoyce

pyamf/tests/test_xml.py

@@ -15,12 +15,31 @@
 from pyamf import util
 
 
-class ElementTreeTestCase(unittest.TestCase):
+class _BaseTestCase(unittest.TestCase):
     """
-    Tests the type mappings.
+    :ivar mod: The concrete xml module that will be used for this test.
     """
 
-    xml = '<foo bar="baz" />'
+    def setUp(self):
+        try:
+            self.etree = util.get_module(self.mod)
+        except ImportError:
+            self.skipTest('%r is not available' % (self.mod,))
+
+        previous_etree = pyamf.set_default_etree(self.etree)
+
+        if previous_etree:
+            self.addCleanup(lambda: pyamf.set_default_etree(previous_etree))
+
+    @classmethod
+    def cls_factory(cls, mod):
+        mod_name = mod.replace('.', '_')
+
+        new_cls = type('%s_%s' % (cls.__name__, mod_name), (cls,), {})
+
+        new_cls.mod = mod
+
+        return new_cls
 
     def check_amf0(self, bytes, xml):
         b = util.BufferedByteStream(bytes)
@@ -42,29 +61,23 @@ def check_amf3(self, bytes, xml):
         self.assertEqual(l >> 1, b.remaining())
         self.assertEqual(b.read(), xml)
 
+    def fromstring(self, xml):
+        return self.etree.fromstring(xml)
 
-for mod in pyamf.xml.ETREE_MODULES:
-    name = 'test_' + mod.replace('.', '_')
+    def tostring(self, element):
+        return self.etree.tostring(element)
 
-    def check_etree(self):
-        # holy hack batman
-        import inspect
-
-        mod = inspect.stack()[1][0].f_locals['testMethod'].__name__[5:]
-        mod = mod.replace('_', '.')
-
-        try:
-            etree = util.get_module(mod)
-        except ImportError:
-            self.skipTest('%r is not available' % (mod,))
 
-        element = etree.fromstring(self.xml)
-        xml = etree.tostring(element)
+class ElementTreeTestCase(_BaseTestCase):
+    """
+    Tests the type mappings.
+    """
 
-        old = pyamf.set_default_etree(etree)
+    xml = '<foo bar="baz" />'
 
-        if old:
-            self.addCleanup(lambda x: pyamf.set_default_etree(x), old)
+    def test_elementtree(self):
+        element = self.fromstring(self.xml)
+        xml = self.tostring(element)
 
         bytes = pyamf.encode(element, encoding=pyamf.AMF0).getvalue()
         self.check_amf0(bytes, xml)
@@ -78,6 +91,31 @@ def check_etree(self):
         new_element = pyamf.decode(bytes, encoding=pyamf.AMF3).next()
         self.assertIdentical(type(element), type(new_element))
 
-    check_etree.__name__ = name
 
-    setattr(ElementTreeTestCase, name, check_etree)
+"""
+This chunk of code turns any subclass of _BaseTestCase in to a set of test
+cases that have a python xml lib module attached to them. This allows the test
+writer to write the test once and ensure that it works for all the supported
+xml modules.
+"""
+for name, value in globals().copy().iteritems():
+    try:
+        is_subclass = issubclass(value, _BaseTestCase)
+    except TypeError:
+        is_subclass = False
+
+    if not is_subclass:
+        continue
+
+    if value is _BaseTestCase:
+        continue
+
+    for mod in pyamf.xml.ETREE_MODULES:
+        mod_test_class = value.cls_factory(mod)
+        globals()[mod_test_class.__name__] = mod_test_class
+
+    del mod, mod_test_class
+
+    globals().pop(name)
+
+del name, value, is_subclass