Ability to mock protected methods with and without return value #845
Conversation
Jason31569
changed the title
| public static object Protected<T>(this T obj, string methodName, params object[] args) where T : class | ||
| { | ||
| if (obj == null) { throw new ArgumentNullException(nameof(obj), "Cannot mock null object"); } | ||
| if (string.IsNullOrWhiteSpace(methodName)) { throw new ArgumentException("Must provide valid protected method name to mock", nameof(methodName)); } | ||
|
|
||
| IList<IArgumentSpecification> argTypes = SubstitutionContext.Current.ThreadContext.PeekAllArgumentSpecifications(); | ||
| MethodInfo mthdInfo = obj.GetType().GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance, Type.DefaultBinder, argTypes.Select(x => x.ForType).ToArray(), null); | ||
|
|
||
| if (mthdInfo == null) { throw new Exception($"Method {methodName} not found"); } | ||
| if (!mthdInfo.IsVirtual) { throw new Exception($"Method {methodName} is not virtual"); } |
There was a problem hiding this comment.
suggestion (nitpick): ideally should use a custom exception(subclassing SubstituteException) with details on what they should do to fix the issue. (see NSubstitute.Exceptions for examples.)
For obj == null, we have NullSubstituteReferenceException. Should also ensure receiver is a substitute otherwise throw NotASubstituteException.
For mthdInfo == null, maybe include arg types checked, something like "No method found with signature Foo(Int, String) on IMySubstitute. Check the method name and arguments are correct."
For non-virtual, can probably use a summary of the warning given in the documentation.
There was a problem hiding this comment.
I made the suggested changes and added additional unit tests to check the error conditions...which helped me find a problem
If you run these tests (in sequence) the second and third test will fail. Removing the first test, the other tests run successfully:
- Should_throw_on_mock_method_arg_mismatch
- Should_throw_on_mock_non_virtual
- Should_throw_on_mock_non_virtual_void_method
I tracked it down to orphaned arg spec from test 1 because ThreadLocalContext.DequeueAllArgumentSpecifications is not invoked when the method is invalid (even if I did not throw exception when method is not virtual). I am now dequeuing all arg specs before I throw exception. Not sure if this is the best approach?
| public IList<IArgumentSpecification> PeekAllArgumentSpecifications() | ||
| { | ||
| var queue = _argumentSpecifications.Value; | ||
| if (queue == null) { throw new SubstituteInternalException("Argument specification queue is null."); } |
There was a problem hiding this comment.
question: do you know under what circumstances this occurs? If it is expected can we just return EmptySpecifications in that case?
There was a problem hiding this comment.
tbh it doesn't look like it could ever be null. I decided to have/keep this in line with enqueue and dequeue methods in case it is something I failed to see
Should we change all 3 (along with enqueue, dequeue) methods to provide a consistent behavior?
There was a problem hiding this comment.
I only changed PeekAllArgumentSpecifications, but happy to update DequeueAllArgumentSpecifications if you think it makes sense
… unit tests to verify error conditions * Rename unit tests with better description * Fix unit test failure due to orphaned argument spec when previous setup throws
Closes #800