Delay wsgi interception until after fixtures

Some WSGI applications require a lot of prior setup before they can
be use. Since we want most of that setup to happen in fixtures,
wsgi-interception is delayed until after all extant fixtures have been
started. This is done with a built in default fixture that is run as
the most deeply nested of the context managers.

The intecept callable is passed on along to the tests so that suite
can be made aware of and use it when using the intercept context
manager. If the callable is a function, when it is passed into the
class builder, it can become bound to the TestCase. This binding is
unbound in the caller.

gabbi/__init__.py

@@ -15,4 +15,4 @@
 # under the License.
 """See gabbi.driver and gabbbi.case."""
 
-__version__ = '0.4.0'
+__version__ = '0.5.0'

gabbi/driver.py

@@ -34,8 +34,6 @@
 import uuid
 
 import httplib2
-import wsgi_intercept
-from wsgi_intercept import httplib2_intercept
 import yaml
 
 from .suite import GabbiSuite
@@ -83,46 +81,33 @@ def build_tests(path, loader, host=None, port=8001, intercept=None,
         test_loader_name = os.path.splitext(os.path.basename(
             test_loader_name[1]))[0]
 
-    if intercept:
-        host = install_intercept(intercept, port)
-
     yaml_file_glob = '%s/*.yaml' % path
 
     # Return an empty suite if we have no host to access, either via
     # a real host or an intercept
     if host or intercept:
         for test_file in glob.iglob(yaml_file_glob):
+            if intercept:
+                host = str(uuid.uuid4())
             test_yaml = load_yaml(test_file)
             test_name = '%s_%s' % (test_loader_name,
                                    os.path.splitext(
                                        os.path.basename(test_file))[0])
             file_suite = test_suite_from_yaml(loader, test_name, test_yaml,
-                                              path, host, port, fixture_module)
+                                              path, host, port, fixture_module,
+                                              intercept)
             top_suite.addTest(file_suite)
     return top_suite
 
 
-def factory(wsgi_app):
-    """Satisfy a bad API."""
-    return wsgi_app
-
-
-def install_intercept(wsgi_callable, port):
-    """Install a wsgi-intercept on a random hostname."""
-    hostname = str(uuid.uuid4())
-    httplib2_intercept.install()
-    wsgi_intercept.add_wsgi_intercept(hostname, port, factory(wsgi_callable))
-    return hostname
-
-
 def load_yaml(yaml_file):
     """Read and parse any YAML file. Let exceptions flow where they may."""
     with open(yaml_file) as source:
         return yaml.safe_load(source.read())
 
 
 def test_suite_from_yaml(loader, test_base_name, test_yaml, test_directory,
-                         host, port, fixture_module):
+                         host, port, fixture_module, intercept):
     """Generate a TestSuite from YAML data."""
 
     file_suite = GabbiSuite()
@@ -160,6 +145,7 @@ def test_suite_from_yaml(loader, test_base_name, test_yaml, test_directory,
                              'fixtures': fixture_classes,
                              'http': httplib2.Http(),
                              'host': host,
+                             'intercept': intercept,
                              'port': port,
                              'prior': prior_test})
 

gabbi/fixture.py

@@ -20,6 +20,8 @@
 from contextlib import contextmanager
 
 import six
+import wsgi_intercept
+from wsgi_intercept import httplib2_intercept
 
 
 class GabbiFixtureError(Exception):
@@ -54,6 +56,24 @@ def stop_fixture(self):
         pass
 
 
+class InterceptFixture(GabbiFixture):
+    """Start up the wsgi intercept. This should not be called directly."""
+
+    httplib2_intercept.install()
+
+    def __init__(self, host, port, app):
+        self.host = host
+        self.port = port
+        self.app = app
+
+    def start_fixture(self):
+        wsgi_intercept.add_wsgi_intercept(self.host, self.port,
+                                          lambda: self.app())
+
+    def stop_fixture(self):
+        wsgi_intercept.remove_wsgi_intercept(self.host, self.port)
+
+
 @contextmanager
 def nest(fixtures):
     """Nest a series of fixtures.

gabbi/suite.py

@@ -39,13 +39,31 @@ def run(self, result, debug=False):
 
         # If there are fixtures, nest in their context.
         fixtures = [fixture.GabbiFixture]
+        intercept = None
+
         try:
-            fixtures = self._tests[0].fixtures
+            first_test = self._tests[0]
+            fixtures = first_test.fixtures
+            host = first_test.host
+            port = first_test.port
+            intercept = first_test.intercept
+
+            # Unbind a passed in WSGI application. During the
+            # metaclass building process intercept becomes bound.
+            try:
+                intercept = intercept.__func__
+            except AttributeError:
+                pass
         except AttributeError:
             pass
+
         try:
             with fixture.nest([fix() for fix in fixtures]):
-                result = super(GabbiSuite, self).run(result, debug)
+                if intercept:
+                    with fixture.InterceptFixture(host, port, intercept):
+                        result = super(GabbiSuite, self).run(result, debug)
+                else:
+                    result = super(GabbiSuite, self).run(result, debug)
         except case.SkipTest as exc:
             [result.addSkip(test, str(exc)) for test in self._tests]