Implement __str__ method for OperationalError: #83

Signed-off-by: Tsuyoshi Hombashi <[email protected]>

simplesqlite/error.py

@@ -56,3 +56,9 @@ def __init__(self, *args: Any, **kwargs: Any) -> None:
         self.__message = kwargs.pop("message", None)
 
         super().__init__(*args)
+
+    def __str__(self) -> str:
+        if not self.message:
+            return ""
+
+        return str(self.message)

test/test_error.py

@@ -0,0 +1,12 @@
+from simplesqlite.error import OperationalError
+
+
+def test_operational_error_str_with_message():
+    error_message = "Test error message"
+    error = OperationalError(message=error_message)
+    assert str(error) == error_message
+
+
+def test_operational_error_str_without_message():
+    error = OperationalError()
+    assert str(error) == ""