Move the zone parameter from the create_test_instance signature #39

The machine type and image are currently read directly from the
provider_test_data when launching a test instance. By following this
pattern for the zone as well we can remove the zone from the signature,
making the code simpler and more consistent.

test/helpers.py

@@ -118,27 +118,26 @@ def delete_test_network(network):
 
 
 def create_test_instance(
-        provider, instance_name, subnet, zone=None, launch_config=None,
+        provider, instance_name, subnet, launch_config=None,
         key_pair=None, security_groups=None):
     return provider.compute.instances.create(
         instance_name,
         get_provider_test_data(provider, 'image'),
         get_provider_test_data(provider, 'instance_type'),
         subnet=subnet,
-        zone=zone,
+        zone=get_provider_test_data(provider, 'placement'),
         key_pair=key_pair,
         security_groups=security_groups,
         launch_config=launch_config)
 
 
 def get_test_instance(provider, name, key_pair=None, security_groups=None,
-                      subnet=None, zone=None):
+                      subnet=None):
     launch_config = None
     instance = create_test_instance(
         provider,
         name,
         subnet=subnet,
-        zone=zone,
         key_pair=key_pair,
         security_groups=security_groups,
         launch_config=launch_config)

test/test_block_store_service.py

@@ -107,9 +107,7 @@ class CloudBlockStoreServiceTestCase(ProviderTestBase):
             net, subnet = helpers.create_test_network(
                 self.provider, instance_name)
             test_instance = helpers.get_test_instance(
-                self.provider, instance_name, subnet=subnet,
-                zone=helpers.get_provider_test_data(self.provider,
-                                                    'placement'))
+                self.provider, instance_name, subnet=subnet)
             name = "CBUnitTestAttachVol-{0}".format(uuid.uuid4())
             test_vol = self.provider.block_store.volumes.create(
                 name, 1, test_instance.zone_id)
@@ -142,9 +140,7 @@ class CloudBlockStoreServiceTestCase(ProviderTestBase):
             net, subnet = helpers.create_test_network(
                 self.provider, instance_name)
             test_instance = helpers.get_test_instance(
-                self.provider, instance_name, subnet=subnet,
-                zone=helpers.get_provider_test_data(self.provider,
-                                                    'placement'))
+                self.provider, instance_name, subnet=subnet)
 
             name = "CBUnitTestVolProps-{0}".format(uuid.uuid4())
             test_vol = self.provider.block_store.volumes.create(

test/test_compute_service.py

@@ -319,8 +319,6 @@ class CloudComputeServiceTestCase(ProviderTestBase):
                         self.provider,
                         name,
                         subnet=subnet,
-                        zone=helpers.get_provider_test_data(self.provider,
-                                                            'placement'),
                         launch_config=lc)
 
                     with helpers.cleanup_action(lambda: