Change py.test config.

Make warnings errors, xpass fail, and document markers.

Author: gsnedders

pytest.ini

@@ -1,2 +1,17 @@
 [pytest]
-addopts = -rXw -p no:doctest
+# Output fails, errors, xpass, and warnings; ignore doctest; make warnings errors
+addopts = -rfEXw -p no:doctest --strict
+
+# Make xpass results be considered fail
+xfail_strict = true
+
+# Document our markers
+markers =
+    DOM: mark a test as a DOM tree test
+    ElementTree: mark a test as a ElementTree tree test
+    cElementTree: mark a test as a cElementTree tree test
+    lxml: mark a test as a lxml tree test
+    genshi: mark a test as a genshi tree test
+    parser: mark a test as a parser test
+    namespaced: mark a test as a namespaced parser test
+    treewalker: mark a test as a treewalker test