Add Deprecated Class unittests (#4448)

* Add Deprecated Class unittests

Author: matusvalo

tests/checkers/unittest_deprecated.py

@@ -15,6 +15,9 @@ def deprecated_methods(self):
     def deprecated_modules(self):
         return {"deprecated_module"}
 
+    def deprecated_classes(self, module):
+        return ["DeprecatedClass"] if module == "deprecated" else []
+
     def deprecated_arguments(self, method):
         if method == "myfunction1":
             # def myfunction1(arg1, deprecated_arg1='spam')
@@ -416,3 +419,55 @@ def test_deprecated_module_from(self):
             )
         ):
             self.checker.visit_importfrom(node)
+
+    def test_deprecated_class_import_from(self):
+        # Tests detecting deprecated class via import from
+        node = astroid.extract_node(
+            """
+        from .deprecated import DeprecatedClass
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-class",
+                args=("DeprecatedClass", "deprecated"),
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_importfrom(node)
+
+    def test_deprecated_class_import(self):
+        # Tests detecting deprecated class via import
+        node = astroid.extract_node(
+            """
+        import deprecated.DeprecatedClass
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-class",
+                args=("DeprecatedClass", "deprecated"),
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_import(node)
+
+    def test_deprecated_class_call(self):
+        # Tests detecting deprecated class via call
+        node = astroid.extract_node(
+            """
+        import deprecated
+        deprecated.DeprecatedClass()
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-class",
+                args=("DeprecatedClass", "deprecated"),
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_call(node)