Add guidance on negative tests in HACKING.rst
Adds guidance on negative tests based on work items from the Newton
design summit in Austin[1].
[1] https://etherpad.openstack.org/p/newton-qa-negative-testing
Change-Id: Ic44b0e17540a5e984006a4a74c8318ad7e74db31
diff --git a/HACKING.rst b/HACKING.rst
index 480650c..432db7d 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -160,11 +160,17 @@
Negative Tests
--------------
-TODO: Write the guideline related to negative tests.
+Error handling is an important aspect of API design and usage. Negative
+tests are a way to ensure that an application can gracefully handle
+invalid or unexpected input. However, as a black box integration test
+suite, Tempest is not suitable for handling all negative test cases, as
+the wide variety and complexity of negative tests can lead to long test
+runs and knowledge of internal implementation details. The bulk of
+negative testing should be handled with project function tests. The
+exception to this rule is API tests used for interoperability testing.
Test skips because of Known Bugs
--------------------------------
-
If a test is broken because of a bug it is appropriate to skip the test until
bug has been fixed. You should use the skip_because decorator so that
Tempest's skip tracking tool can watch the bug status.