@allending The current syntax is correct. The given block accepts the arguments and utilizes them in the block implementation, you do not provide them in the moment of stubbing. What provides the arguments is the actual method call, Kiwi simply fills them into the array.

```
[foo stub:@selector(bar:) withBlock:(id ^(NSArray *params) {
    foo.zing = params[0];
});
[foo bar:@"cocoa"];
[[foo.zing should] equal:@"cocoa"];
```