tests: Add pydle.featurize() tests.

tests/test_featurize.py

@@ -0,0 +1,52 @@
+import pydle
+from .mocks import MockClient
+from .fixtures import with_client
+
+
+def with_errorcheck_client(*features):
+    def inner(f):
+        def run():
+            try:
+                return with_client(*features, connected=False)(f)()
+            except TypeError as e:
+                assert False, e
+        run.__name__ = f.__name__
+        return run
+    return inner
+
+def assert_mro(client, *features):
+    # Skip FeaturizedClient, MockClient, pydle.BasicClient and object classes.
+    assert client.__class__.__mro__[2:-2] == features
+
+class FeatureClass(pydle.BasicClient):
+    pass
+
+class SubFeatureClass(FeatureClass):
+    pass
+
+class SubBFeatureClass(FeatureClass):
+    pass
+
+class DiamondFeatureClass(SubBFeatureClass, SubFeatureClass):
+    pass
+
+
+@with_errorcheck_client()
+def test_featurize_basic(server, client):
+    assert_mro(client)
+
+@with_errorcheck_client(FeatureClass)
+def test_featurize_multiple(server, client):
+    assert_mro(client, FeatureClass)
+
+@with_errorcheck_client(SubFeatureClass)
+def test_featurize_inheritance(server, client):
+    assert_mro(client, SubFeatureClass, FeatureClass)
+
+@with_errorcheck_client(FeatureClass, SubFeatureClass)
+def test_featurize_inheritance_ordering(server, client):
+    assert_mro(client, SubFeatureClass, FeatureClass)
+
+@with_errorcheck_client(SubBFeatureClass, SubFeatureClass, DiamondFeatureClass)
+def test_featurize_inheritance_diamond(server, client):
+    assert_mro(client, DiamondFeatureClass, SubBFeatureClass, SubFeatureClass, FeatureClass)