Allow matchers in expected value in with_data chain

README.md

@@ -82,6 +82,17 @@ Checking for an included resource:
 expect(response_body['included'])
   .to include(have_type('posts').and have_id('1'))
 ```
+
+Combining `have_relationship.with_data` matcher with other matchers:
+
+```ruby
+expect(response_body)
+  .to have_relationship(:posts).with_data(include(have_id('1')))
+
+expect(response_body)
+  .to have_relationship(:posts).with_data(all(have_type('post')))
+```
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at

lib/jsonapi/rspec/relationships.rb

@@ -6,18 +6,18 @@ module Relationships
           actual = JSONAPI::RSpec.as_indifferent_hash(actual)
           return false unless (actual['relationships'] || {}).key?(rel.to_s)
 
-          !@data_set || actual['relationships'][rel.to_s]['data'] == @data_val
+          !@data_set || values_match?(@data_val, actual['relationships'][rel.to_s]['data'])
         end
 
         chain :with_data do |val|
           @data_set = true
-          @data_val = JSONAPI::RSpec.as_indifferent_hash(val)
+          @data_val = ::RSpec::Matchers.is_a_matcher?(val) ? val : JSONAPI::RSpec.as_indifferent_hash(val)
         end
 
         failure_message do |actual|
           if (actual['relationships'] || {}).key?(rel.to_s)
             "expected #{actual['relationships'][rel.to_s]} " \
-              "to have data #{@data_val}"
+              "to have data #{description_of(@data_val)}"
           else
             "expected #{actual} to have relationship #{rel}"
           end

spec/jsonapi/relationships_spec.rb

@@ -41,6 +41,12 @@
     )
   end
 
+  it do
+    expect(doc).to have_relationship('comments').with_data(
+      include(have_id('1').and(have_type('comment')))
+    )
+  end
+
   context 'with jsonapi indifferent hash enabled' do
     before(:all) { ::RSpec.configuration.jsonapi_indifferent_hash = true }
     after(:all) { ::RSpec.configuration.jsonapi_indifferent_hash = false }