[WIP]Extends tests for ModuleStream.depends_on_stream()

The tests for depends_on_stream() and build_depends_on_stream() is modified to handle empty lists

issue: fedora-modularity#192

modulemd/v2/tests/ModulemdTests/modulestream.py

@@ -1036,7 +1036,16 @@ def test_depends_on_stream(self):
                     'platform', 'f28'), False)
 
             self.assertEqual(stream.depends_on_stream('base', 'f30'), False)
-            self.assertEqual(stream.depends_on_stream('base', 'f30'), False)
+            self.assertEqual(
+                stream.build_depends_on_stream(
+                    'base', 'f30'), False)
+
+            self.assertEqual(
+                stream.depends_on_stream(
+                    'streamname', 'f30'), True)
+            self.assertEqual(
+                stream.build_depends_on_stream(
+                    'streamname', 'f30'), True)
 
 
 if __name__ == '__main__':

modulemd/v2/tests/test_data/dependson_v2.yaml

@@ -13,9 +13,12 @@ data:
     - MIT
   dependencies:
   - buildrequires:
-      platform: [ f30 ]
+      platform: [f30]
+      streamname: [ ] 
     requires:
       platform: [ -f28 ]
+      streamname: [ ]
+
   references:
     community: http://nodejs.org
     documentation: http://nodejs.org/en/docs