Do not fork actor execution with snactor fixture

Previously running an actor within a test caused the test to be executed
in a forked process and when it was executing the actor the actor was
also being executed in another forked process.

This patch is removing the latter fork from being done to allow easier
mocking and testing.

Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>

Author: vinzenz

leapp/repository/actor_definition.py

@@ -33,7 +33,7 @@ class ActorCallContext(object):
     """
     Wraps the actor execution into child process.
     """
-    def __init__(self, definition, logger, messaging):
+    def __init__(self, definition, logger, messaging, within_pytest=False):
         """
         :param definition: Actor definition
         :type definition: :py:class:`leapp.repository.actor_definition.ActorDefinition`
@@ -45,6 +45,7 @@ def __init__(self, definition, logger, messaging):
         self.definition = definition
         self.logger = logger
         self.messaging = messaging
+        self.within_pytest = within_pytest
 
     @staticmethod
     def _do_run(stdin, logger, messaging, definition, args, kwargs):
@@ -53,6 +54,10 @@ def _do_run(stdin, logger, messaging, definition, args, kwargs):
                 sys.stdin = os.fdopen(stdin)
             except OSError:
                 pass
+        self._do_run_impl(logger, messaging, definition, args, kwargs)
+
+    @staticmethod
+    def _do_run_impl(logger, messaging, definition, args, kwargs)
         definition.load()
         with definition.injected_context():
             target_actor = [actor for actor in get_actors() if actor.name == definition.name][0]
@@ -62,17 +67,20 @@ def run(self, *args, **kwargs):
         """
         Performs the actor execution in the child process.
         """
-        try:
-            stdin = sys.stdin.fileno()
-        except UnsupportedOperation:
-            stdin = None
-        p = Process(target=self._do_run, args=(stdin, self.logger, self.messaging, self.definition, args, kwargs))
-        p.start()
-        p.join()
-        if p.exitcode != 0:
-            raise LeappRuntimeError(
-                'Actor {actorname} unexpectedly terminated with exit code: {exitcode}'
-                .format(actorname=self.definition.name, exitcode=p.exitcode))
+        if self.within_pytest:
+            self._do_run_impl(self.logger, self.messaging, self.definition, args, kwargs)
+        else:
+            try:
+                stdin = sys.stdin.fileno()
+            except UnsupportedOperation:
+                stdin = None
+            p = Process(target=self._do_run, args=(stdin, self.logger, self.messaging, self.definition, args, kwargs))
+            p.start()
+            p.join()
+            if p.exitcode != 0:
+                raise LeappRuntimeError(
+                    'Actor {actorname} unexpectedly terminated with exit code: {exitcode}'
+                    .format(actorname=self.definition.name, exitcode=p.exitcode))
 
 
 class ActorDefinition(object):
@@ -168,8 +176,8 @@ def discover(self):
                     tag.actors += (self,)
         return self._discovery
 
-    def __call__(self, messaging=None, logger=None):
-        return ActorCallContext(definition=self, messaging=messaging, logger=logger)
+    def __call__(self, messaging=None, logger=None, within_pytest=False):
+        return ActorCallContext(definition=self, messaging=messaging, logger=logger, within_pytest=within_pytest)
 
     @property
     def dialogs(self):

leapp/snactor/fixture.py

@@ -101,7 +101,7 @@ def run(self):
 
         :return: None
         """
-        self._actor(messaging=self._messaging).run()
+        self._actor(messaging=self._messaging, within_pytest=True).run()
 
     def messages(self):
         """