rspec users - Nov 2010 - Question: Define custom matcher like raise_error, by Matchers.define

I have a question about the custom matcher using Matcher#define.

My intention is given by the following code:

=======================================================================Spec::Matchers.define
:be_done do
   match do |block|
     block.call
     true
   end

   failure_message_for_should do
     "be_done failed."
   end
end

describe "The expectation failure in block called from the custom  
matcher" do
   example "should be reported." do
     lambda {
       lambda {
         1.should == 2
       }.should be_done
     }.should_not raise_error(/be_done failed/)   # should ''expected:  
2, got: 1 (using ==)''
   end
end
=======================================================================
I want to define the custom matcher that it calls the block given as  
the actual value, like raise_error.
But if the expectation in the given block failed,
it is not reported, but it reports the custom matcher''s failure.

Is there some misuse about Matchers.define in my code?

Best Regards.
--
Kaoru Kobo

On Nov 24, 2010, at 11:09 PM, ???? wrote:
> I have a question about the custom matcher using Matcher#define.
> 
> My intention is given by the following code:
> 
> =======================================================================>
Spec::Matchers.define :be_done do
>  match do |block|
>    block.call
>    true
>  end
This should work:

match do |block|
  begin
    block.call
    true
  rescue
    false
  end
end

Or, if you prefer one liners:

match do |block|
  (block.call; true) rescue false
end

HTH,
David
> 
>  failure_message_for_should do
>    "be_done failed."
>  end
> end
> 
> describe "The expectation failure in block called from the custom
matcher" do
>  example "should be reported." do
>    lambda {
>      lambda {
>        1.should == 2
>      }.should be_done
>    }.should_not raise_error(/be_done failed/)   # should
''expected: 2, got: 1 (using ==)''
>  end
> end
> =======================================================================>
> I want to define the custom matcher that it calls the block given as the
actual value, like raise_error.
> But if the expectation in the given block failed,
> it is not reported, but it reports the custom matcher''s failure.
> 
> Is there some misuse about Matchers.define in my code?
> 
> Best Regards.
> --
> Kaoru Kobo
> 
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users

Thanks, David.
>
> This should work:
> ...
> match do |block|
>  (block.call; true) rescue false
> end
I tried that, but the spec still fails...

1)
''The expectation failure in block called from the custom matcher  
should be reported.'' FAILED
expected no Exception with message matching /be_done failed/, got  
#<Spec::Expectations::ExpectationNotMetError: be_done failed.>
./spec/custom_matcher_spec.rb:21:

I expect that it fails with message ''expected: 2, got: 1 (using
==)''.

Best Regards.
--
Kaoru Kobo

Then I found this page:

?Upgrade to 1.3.0 - Matcher DSL"
Upgrade.rdoc at master from dchelimsky''s rspec - GitHub
http://github.com/dchelimsky/rspec/blob/master/Upgrade.rdoc


and, I found the tentative solution:
(Is there the better way?)

======================================================================= 
Spec::Matchers.define :be_done do
-  match do |block|
+  # Do not turn any exceptions to false.
+  match_unless_raises(Class.new(Exception)) do |block|
      block.call
      true
    end
=======================================================================
Best Regards.
--
Kaoru Kobo

On Nov 25, 2010, at 7:16 PM, Kaoru Kobo wrote:
> Then I found this page:
> 
> ?Upgrade to 1.3.0 - Matcher DSL"
> Upgrade.rdoc at master from dchelimsky''s rspec - GitHub
> http://github.com/dchelimsky/rspec/blob/master/Upgrade.rdoc
> 
> 
> and, I found the tentative solution:
> (Is there the better way?)
Actually, match_unless_raises is probably the best solution for your issue.
> 
> =======================================================================>
Spec::Matchers.define :be_done do
> -  match do |block|
> +  # Do not turn any exceptions to false.
> +  match_unless_raises(Class.new(Exception)) do |block|
>     block.call
>     true
>   end
> =======================================================================>
> Best Regards.
> --
> Kaoru Kobo

David

Thanks!
>
> Actually, match_unless_raises is probably the best solution for your  
> issue.
>>
>> Then I found this page:
>>
>> ?Upgrade to 1.3.0 - Matcher DSL"
>> Upgrade.rdoc at master from dchelimsky''s rspec - GitHub
>> http://github.com/dchelimsky/rspec/blob/master/Upgrade.rdoc
>>
>> and, I found the tentative solution:
>> (Is there the better way?)