I believe the expectation matchers also now support === in RSpec 3. So you
could write it as:
it "works using expectation matcher" do
expect{ |b| Foo.new(&b) }.to yield_with_args instance_of Fooend
On Fri, Nov 15, 2013 at 10:59 AM, Myron Marston <[email protected]>wrote:
> 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 instanceoccurrence 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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