Allow a fixture to cause a file to skip all tests

If a fixture class raises unittest.case.SkipTest then all the tests
in the YAML file associated with that test will be skipped.

docs/source/fixtures.rst

@@ -15,3 +15,9 @@ any direct awareness of the fixtures. The fixtures exist, instead, on the
 inside of the API being tested. Their most common function is
 expected to be the creation of sample data, by whatever means make
 sense for the system being tested.
+
+If a fixture raises ``unittest.case.SkipTest`` during
+``start_fixture`` all the tests in the current file will be skipped.
+This makes it possible to skip the tests if some optional
+configuration (such as a particular type of database) is not
+available.

gabbi/__init__.py

@@ -15,4 +15,4 @@
 # under the License.
 """See gabbi.driver and gabbbi.case."""
 
-__version__ = '0.3.3'
+__version__ = '0.4.0'

gabbi/suite.py

@@ -14,6 +14,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from unittest import case
 from unittest import suite
 
 from . import fixture
@@ -24,6 +25,9 @@ class GabbiSuite(suite.TestSuite):
 
     The suite wraps the tests with a set of nested context managers that
     operate as fixtures.
+
+    If a fixture raises unittest.case.SkipTest during setup, all the
+    tests in this suite will be skipped.
     """
 
     def run(self, result, debug=False):
@@ -39,7 +43,10 @@ def run(self, result, debug=False):
             fixtures = self._tests[0].fixtures
         except AttributeError:
             pass
-        with fixture.nest([fix() for fix in fixtures]):
-            result = super(GabbiSuite, self).run(result, debug)
+        try:
+            with fixture.nest([fix() for fix in fixtures]):
+                result = super(GabbiSuite, self).run(result, debug)
+        except case.SkipTest as exc:
+            [result.addSkip(test, str(exc)) for test in self._tests]
 
         return result