Can OCMock run a block parameter?

Question

Assume a method signature such as the following:

- (void)theMethod:(void(^)(BOOL completed))completionBlock;

I would like to mock this method signature to ensure the method is called, and just call the completion block. I see from other posts like this one that I can mock the method call and accept any block, but not run the block. I also know there is a andDo method that I might be able to use, but I can't figure out how to pass a block in and run it.

Any ideas?

Thanks.

Answer 1

You can use [[mock stub] andDo:] like this to pass another block that gets called when your mocked method is called:

void (^proxyBlock)(NSInvocation *) = ^(NSInvocation *invocation) {
     void (^passedBlock)( BOOL );
     [invocation getArgument: &passedBlock atIndex: 2];
};
[[[mock stub] andDo: proxyBlock] theMethod:[OCMArg any]];

The block gets a NSInvocation instance from which you can query all the used arguments. Note that the first argument is at index 2 since you have self and _cmd at the indices 0 and 1.

Answer 2

EDIT 2: Use https://stackoverflow.com/a/32945785/637641 instead.

Using andDo: is perfectly fine, but personally I prefer [OCMArg checkWithBlock:].

[[mock expect] theMethod:[OCMArg checkWithBlock:^BOOL(id param)
{
    void (^passedBlock)( BOOL ) = param;
    // Normally I set some expectations here and then call the block.
    return YES;
}]];

// Code to test

[mock verify];

You can use also [mock stub] but I prefer to verify that theMethod is called.

EDIT 1

OCMock 3 version:

OCMExpect([mock theMethod:[OCMArg checkWithBlock:^BOOL(void (^passedBlock)(BOOL))
{
    // call the block...
    return YES;
}]]);

// Code to test

OCMVerify(mock);

Answer 3

This is now supported in OCMock 3.2. You can use [OCMArg invokeBlock] and [OCMArg invokeBlockWithArgs:...] to invoke the block passed as an argument to a stubbed method.

Answer 4

Using andDo: blocks is sometimes required but for most cases you can use [OCMArg invokeBlock] or [OCMArg invokeBlockWithArgs:].

In your example you can do the following
If you don't care about the arguments:

// Call block with default arguments.
OCMStub([mock theMethod:[OCMArg invokeBlock]];

If you want to send specific arguments:

// Call block with YES.
OCMStub([mock theMethod:([OCMArg invokeBlockWithArgs:@YES, nil])];

Note the nil termination since you can pass multiple arguments to this method. In addition the entire expression must be wrapped in parentheses.

You can read more about it in the OCMock documentation.