add callback unit tests.

callback deregister now accepts iterable.

tests/test_callback.py

@@ -0,0 +1,59 @@
+import pytest
+from obsstudio_sdk.callback import Callback
+
+
+class TestCallbacks:
+    __test__ = True
+
+    @classmethod
+    def setup_class(cls):
+        cls.callback = Callback()
+
+    @pytest.fixture(autouse=True)
+    def wraps_tests(self):
+        yield
+        self.callback.clear()
+
+    def test_register_callback(self):
+        def on_callback_method():
+            pass
+
+        self.callback.register(on_callback_method)
+        assert self.callback.get() == ["CallbackMethod"]
+
+    def test_register_callbacks(self):
+        def on_callback_method_one():
+            pass
+
+        def on_callback_method_two():
+            pass
+
+        self.callback.register((on_callback_method_one, on_callback_method_two))
+        assert self.callback.get() == ["CallbackMethodOne", "CallbackMethodTwo"]
+
+    def test_deregister_callback(self):
+        def on_callback_method_one():
+            pass
+
+        def on_callback_method_two():
+            pass
+
+        self.callback.register((on_callback_method_one, on_callback_method_two))
+        self.callback.deregister(on_callback_method_one)
+        assert self.callback.get() == ["CallbackMethodTwo"]
+
+    def test_deregister_callbacks(self):
+        def on_callback_method_one():
+            pass
+
+        def on_callback_method_two():
+            pass
+
+        def on_callback_method_three():
+            pass
+
+        self.callback.register(
+            (on_callback_method_one, on_callback_method_two, on_callback_method_three)
+        )
+        self.callback.deregister((on_callback_method_two, on_callback_method_three))
+        assert self.callback.get() == ["CallbackMethodOne"]

tests/test_request.py

@@ -1,5 +1,3 @@
-import time
-
 import pytest
 
 from tests import req_cl