Add test for BoundResult.exit and fix bug on it

src/fieldenum/enums.py

@@ -246,7 +246,7 @@ def as_option(self) -> Option[R]:
                 unreachable(other)
 
     def exit(self, error_code: str | int | None = 1) -> NoReturn:
-        sys.exit(error_code if self else 0)
+        sys.exit(0 if self else error_code)
 
     def rebound[NewBound: BaseException](self, bound: type[NewBound], /) -> BoundResult[R, NewBound]:
         match self:

tests/test_enums.py

@@ -89,6 +89,23 @@ def test_bound_result():
     ) == BoundResult.Failed(error, Exception)
 
 
+    with pytest.raises(SystemExit) as exc:
+        BoundResult.Success("success", Exception).exit()
+    assert exc.value.code == 0
+
+    with pytest.raises(SystemExit) as exc:
+        BoundResult.Failed(error, Exception).exit()
+    assert exc.value.code == 1
+
+    with pytest.raises(SystemExit) as exc:
+        BoundResult.Failed(error, Exception).exit("failed miserably...")
+    assert exc.value.code == "failed miserably..."
+
+    with pytest.raises(SystemExit) as exc:
+        BoundResult.Failed(error, Exception).exit(None)
+    assert exc.value.code == None
+
+
 @pytest.mark.parametrize(
     "second_param",
     [True, False],