add exceptions tests

Author: chrissimpkins

tests/test_exceptions.py

@@ -0,0 +1,16 @@
+from fdiff.exceptions import AIOError
+
+import pytest
+
+
+def raise_aioerror(message):
+    raise AIOError(message)
+
+
+def test_aioerror_raises():
+    with pytest.raises(AIOError) as e:
+        raise_aioerror("Test message")
+
+    assert str(e.value) == "Test message"
+
+