relationships updates

Author: chadcarlson

platformshconfig/config.py

@@ -381,6 +381,21 @@ def formatted_credentials(self, relationship, formatter):
             )
         return self.credentialFormatters[formatter](self.credentials(relationship))
 
+
+    def has_relationship(self, relationship):
+        """Determines if a relationship is defined, and thus has credentials available.
+
+        Args:
+            relationship (string):
+                The name of the relationship to check.
+
+        Returns:
+            bool:
+                True if the relationship is defined, False otherwise.
+
+        """
+        return relationship in self.relationshipsDef
+
     def __getitem__(self, item):
         """Reads an environment variable, taking the prefix into account.
 

tests/test_config.py

@@ -193,22 +193,38 @@ def test_credentials_missing_relationship_throws(self):
         with self.assertRaises(KeyError):
             config.credentials('does-not-exist')
 
-    def test_reading_existing_variable_works(self):
+    def test_credentials_missing_relationship_index_throws(self):
 
         env = self.mockEnvironmentDeploy
 
         config = Config(env)
 
-        self.assertEqual('someval', config.variable('somevar'))
+        with self.assertRaises(KeyError):
+            config.credentials('database', 3)
 
-    def test_credentials_missing_relationship_index_throws(self):
+    def test_has_relationship_returns_true_for_existing_relationship(self):
 
         env = self.mockEnvironmentDeploy
 
         config = Config(env)
 
-        with self.assertRaises(KeyError):
-            config.credentials('database', 3)
+        self.assertTrue(config.has_relationship('database'))
+
+    def test_has_relationship_returns_false_for_missing_relationship(self):
+
+        env = self.mockEnvironmentDeploy
+
+        config = Config(env)
+
+        self.assertFalse(config.has_relationship('missing'))
+
+    def test_reading_existing_variable_works(self):
+
+        env = self.mockEnvironmentDeploy
+
+        config = Config(env)
+
+        self.assertEqual('someval', config.variable('somevar'))
 
     def test_reading_missing_variable_returns_default(self):