Add support for rspec-mocks argument macthers

[wata727]

This PR adds support for diffing rspec-mocks argument matchers. I often use hash_including in rspec-mocks instead of a_hash_including in rspec-expectations for partial hash comparisons. SuperDiff shows a great diff for a_hash_including, but hash_including doesn't.

In rspec-mocks, there is an argument matcher similar to the matcher provided by rspec-expectations. This PR is primarily aimed at them. The following support has been added:

• hash_including (similar to a_hash_including)
• array_including (similar to a_collection_including)
• kind_of (similar to a_kind_of)
• instance_of (similar to an_instance_of)

Other than that, rspec-mocks provides useful matchers (e.g. hash_excluding, duck_type`, etc.), but they are out of scope here.

Before

Failures:

  1) is expected to match { a: #<RSpec::Mocks::ArgumentMatchers::HashIncludingMatcher:0x00007f92fca5a4d8 @expected={:b=>{:c=>{:d=>2}}}> }
     Failure/Error: expect({ a: { b: { c: { d: 1 }}} }).to match({ a: hash_including(b: { c: { d: 2 } }) })

       Expected { a: { b: { c: { d: 1 } } } }
       to match { a: #<RSpec::Mocks::ArgumentMatchers::HashIncludingMatcher:0x00007f92fca5a4d8 @expected={:b=>{:c=>{:d=>2}}}> }

       Diff:

       ┌ (Key) ──────────────────────────┐
       │ ‹-› in expected, not in actual  │
       │ ‹+› in actual, not in expected  │
       │ ‹ › in both expected and actual │
       └─────────────────────────────────┘
         {
       -   a: #<RSpec::Mocks::ArgumentMatchers::HashIncludingMatcher:0xaf0 {
       -     @expected={
       -       b: {
       -         c: {
       -           d: 2
       -         }
       -       }
       -     }
       -   }>
       +   a: {
       +     b: {
       +       c: {
       +         d: 1
       +       }
       +     }
       +   }
         }

After

Failures:

  1) is expected to match { a: #<a hash including (b: { c: { d: 2 } })> }
     Failure/Error: expect({ a: { b: { c: { d: 1 }}} }).to match({ a: hash_including(b: { c: { d: 2 } }) })

       Expected { a: { b: { c: { d: 1 } } } } to match { a: #<a hash including (b: { c: { d: 2 } })> }.

       Diff:

       ┌ (Key) ──────────────────────────┐
       │ ‹-› in expected, not in actual  │
       │ ‹+› in actual, not in expected  │
       │ ‹ › in both expected and actual │
       └─────────────────────────────────┘

         {
           a: {
             b: {
               c: {
       -         d: 2
       +         d: 1
               }
             }
           }
         }

Finally, thank you for the great gem. In our project, we had a problem that the diff of the request spec comparing huge JSON was very hard to read, but this gem solved it brilliantly.

[wata727]

I understand this is a bad practice, but unfortunately, the rspec-mocks matcher didn't have a public interface to access the values.
https://github.com/rspec/rspec-mocks/blob/v3.10.2/lib/rspec/mocks/argument_matchers.rb#L231-L259

[mcmire]

Makes sense! (I also do this in other places)

[mcmire]

I had a few little comments but overall this is a nice PR, thank you for doing this!

[mcmire]

Nitpick: What do you think about formatting it like this so the grouping is easier to parse?

(
  SuperDiff::RSpec.a_collection_including_something?(expected) ||
  SuperDiff::RSpec.array_including_something?(expected)
) && actual.is_a?(::Array)

or

(
  SuperDiff::RSpec.a_collection_including_something?(expected) ||
  SuperDiff::RSpec.array_including_something?(expected)
) &&
actual.is_a?(::Array)

[wata727]

Makes sense. Fixed https://github.com/mcmire/super_diff/compare/c98b483c0c8d7787f1eb0d57de913ce12849b370..60938bd4a380d87b075dbdc3ff7e047085a1ebdd

[mcmire]

Makes sense! (I also do this in other places)

[mcmire]

This is great! Thanks so much for adding this!

[mcmire]

Now available in v0.7.0!