Thanks for trying out the 3.0 beta :).
The yield matchers try to match the args with both `===` (for case
equality) and `==` (for exact equality) and in 1.9+, lambda's respond to
`===` by invoking their logic. So while it's a bit of a hack, this works:
it 'works using a lambda' do
instance = nil
equals_the_instance = ->(arg) { arg.equal?(instance) }
expect { |b|
instance = Test.new(&b)
}.to yield_with_args(equals_the_instance)
end
It works because passing the lambda causes it to be lazily evaluated.
That said, I don't think the `yield_with_args` matcher offers you much
advantage in this case. It's simpler to do this:
it 'works without the matcher' do
yielded = []
instance = Test.new { |a| yielded << a }
expect(yielded).to eq([instance])
end
HTH,
Myron
On Friday, November 15, 2013 2:36:20 AM UTC-8, Maurizio De Santis wrote:
>
> Hello,
>
> I'm using rspec 3.0.0.beta1. I'm trying to test for yield self. Example:
>
> class Test
> def initialize
> yield self if block_given?
> end
> end
>
> I can't figure out how to test it. This is the closest successful test I
> wrote:
>
> describe Test do
> context 'giving a block with one argument' do
> it 'yields itself'
> expect { |b| described_class.new &b }.to yield_with_args
> described_class
> end
> end
> end
>
> But it tests only the yield argument type, not the object identity.
>
> This is a failing test that goes close to the wanted result:
>
> describe Test do
> context 'giving a block with one argument' do
> it 'yields itself'
> instance = nil
> expect { |b|
> instance = described_class.new &b
> }.to yield_with_args instance
> end
> end
> end
>
> Indeed it fails, since that at the time that the last instance occurrence
> is evaluated its value is nil, so it doesn't match with instance value at
> the block evaluation time.
>
> Do you have some ideas about?
>
> Thank you
>
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