Migrate the skip_because decorator from tempest

This commit migrates the skip_because decorator out of tempest into
tempest-lib. Since it is included as parts of existing files the
migration script wasn't used to generate tempest sha1s to preserve
history.

Change-Id: I2c9551d3f9ca23bc9b204a652a87c6eb10bbac9a

tempest_lib/decorators.py

@@ -0,0 +1,42 @@
+# Copyright 2015 Hewlett-Packard Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import functools
+
+import testtools
+
+
+def skip_because(*args, **kwargs):
+    """A decorator useful to skip tests hitting known bugs
+
+    @param bug: bug number causing the test to skip
+    @param condition: optional condition to be True for the skip to have place
+    """
+    def decorator(f):
+        @functools.wraps(f)
+        def wrapper(self, *func_args, **func_kwargs):
+            skip = False
+            if "condition" in kwargs:
+                if kwargs["condition"] is True:
+                    skip = True
+            else:
+                skip = True
+            if "bug" in kwargs and skip is True:
+                if not kwargs['bug'].isdigit():
+                    raise ValueError('bug must be a valid bug number')
+                msg = "Skipped until Bug: %s is resolved." % kwargs["bug"]
+                raise testtools.TestCase.skipException(msg)
+            return f(self, *func_args, **func_kwargs)
+        return wrapper
+    return decorator

tempest_lib/tests/test_decorators.py

@@ -0,0 +1,59 @@
+# Copyright 2013 IBM Corp
+# Copyright 2015 Hewlett-Packard Development Company, L.P.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import testtools
+
+from tempest_lib import base as test
+from tempest_lib import decorators
+from tempest_lib.tests import base
+
+
+class TestSkipBecauseDecorator(base.TestCase):
+    def _test_skip_because_helper(self, expected_to_skip=True,
+                                  **decorator_args):
+        class TestFoo(test.BaseTestCase):
+            _interface = 'json'
+
+            @decorators.skip_because(**decorator_args)
+            def test_bar(self):
+                return 0
+
+        t = TestFoo('test_bar')
+        if expected_to_skip:
+            self.assertRaises(testtools.TestCase.skipException, t.test_bar)
+        else:
+            # assert that test_bar returned 0
+            self.assertEqual(TestFoo('test_bar').test_bar(), 0)
+
+    def test_skip_because_bug(self):
+        self._test_skip_because_helper(bug='12345')
+
+    def test_skip_because_bug_and_condition_true(self):
+        self._test_skip_because_helper(bug='12348', condition=True)
+
+    def test_skip_because_bug_and_condition_false(self):
+        self._test_skip_because_helper(expected_to_skip=False,
+                                       bug='12349', condition=False)
+
+    def test_skip_because_bug_without_bug_never_skips(self):
+        """Never skip without a bug parameter."""
+        self._test_skip_because_helper(expected_to_skip=False,
+                                       condition=True)
+        self._test_skip_because_helper(expected_to_skip=False)
+
+    def test_skip_because_invalid_bug_number(self):
+        """Raise ValueError if with an invalid bug number"""
+        self.assertRaises(ValueError, self._test_skip_because_helper,
+                          bug='critical_bug')