Add belongs_to matchers

lib/active_model_serializers_matchers.rb

@@ -2,6 +2,10 @@
 Dir[Pathname(__FILE__).join('../**/*.rb')].each { |f| require f }
 
 module ActiveModelSerializersMatchers
+  def belong_to(association_root)
+    AssociationMatcher.new(association_root, :belongs_to)
+  end
+
   def have_many(association_root)
     AssociationMatcher.new(association_root, :has_many)
   end

lib/active_model_serializers_matchers/association_matcher/association_check.rb

@@ -29,6 +29,8 @@ def failure_message
 
       def association_string
         case type
+        when :belongs_to
+          'belong to'
         when :has_one
           'have one'
         when :has_many
@@ -38,6 +40,8 @@ def association_string
 
       def association_reflection
         case type
+        when :belongs_to
+          ActiveModel::Serializer::BelongsToReflection
         when :has_one
           ActiveModel::Serializer::HasOneReflection
         when :has_many

spec/active_model_serializers_matchers/association_matcher_spec.rb

@@ -236,4 +236,113 @@
       end
     end
   end
+
+  ###
+
+  context 'when given serializer that belongs_to :foo' do
+    subject do
+      Class.new(ActiveModel::Serializer) { belongs_to :foo }
+    end
+    it_behaves_like 'it belongs_to :foo'
+    it_behaves_like 'it belongs_to :foo and no key'
+    it_behaves_like 'it belongs_to :foo and no serializer'
+    it_behaves_like 'it belongs_to :foo and no embed_key'
+  end
+
+  context 'when given serializer that belongs_to :foo, key: :bar' do
+    subject do
+      Class.new(ActiveModel::Serializer) { belongs_to :foo, key: :bar }
+    end
+    it_behaves_like 'it belongs_to :foo'
+    it_behaves_like 'it belongs_to :foo and no serializer'
+    it_behaves_like 'it belongs_to :foo and no embed_key'
+    it_behaves_like 'it belongs_to :foo with key :bar'
+  end
+
+  context 'when given serializer that belongs_to :foo, serializer: FooSerializer' do
+    subject do
+      Class.new(ActiveModel::Serializer) { belongs_to :foo, serializer: FooSerializer }
+    end
+    it_behaves_like 'it belongs_to :foo'
+    it_behaves_like 'it belongs_to :foo and no key'
+    it_behaves_like 'it belongs_to :foo and no embed_key'
+    it_behaves_like 'it belongs_to :foo with serializer FooSerializer'
+  end
+
+  context 'when given serializer that belongs_to :foo, embed_key: :foo_external_id' do
+    subject do
+      Class.new(ActiveModel::Serializer) { belongs_to :foo, embed_key: :foo_external_id }
+    end
+    it_behaves_like 'it belongs_to :foo'
+    it_behaves_like 'it belongs_to :foo and no key'
+    it_behaves_like 'it belongs_to :foo and no serializer'
+    it_behaves_like 'it belongs_to :foo with embed_key :foo_external_id'
+  end
+
+  context 'when given serializer that belongs_to :foo, key: :bar, serializer: FooSerializer' do
+    subject do
+      Class.new(ActiveModel::Serializer) { belongs_to :foo, key: :bar, serializer: FooSerializer }
+    end
+    it_behaves_like 'it belongs_to :foo'
+    it_behaves_like 'it belongs_to :foo with key :bar'
+    it_behaves_like 'it belongs_to :foo with serializer FooSerializer'
+
+    describe 'should if all chained expectations pass in any order' do
+      it 'should pass a belong_to :foo as :bar serialized_with FooSerializer expectation' do
+        expectation = belong_to(:foo).as(:bar).serialized_with(FooSerializer)
+        expect(subject).to expectation
+        expect(expectation.description).to eq('belong to :foo as :bar serialized with FooSerializer')
+      end
+
+      it 'should pass a belong_to :foo serialized_with FooSerializer as :bar expectation' do
+        expectation = belong_to(:foo).serialized_with(FooSerializer).as(:bar)
+        expect(subject).to expectation
+        expect(expectation.description).to eq('belong to :foo serialized with FooSerializer as :bar')
+      end
+    end
+
+    describe 'should fail with the first encountered expectation message if any chained expectations fail' do
+      it 'should fail a belong_to :fuu expectation' do
+        failure_message = "expected #{ subject } to define a 'belongs_to :fuu' association"
+        expect {
+          expect(subject).to belong_to(:fuu).as(:bar).serialized_with(FooSerializer)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:fuu).serialized_with(FooSerializer).as(:bar)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:fuu).as(:bor).serialized_with(BarSerializer)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:fuu).serialized_with(BarSerializer).as(:bor)
+        }.to fail_with(failure_message)
+      end
+
+      it 'should fail a belong_to :foo serialized with BarSerializer expectation' do
+        failure_message = "expected #{ subject } 'belongs_to :foo' association to explicitly have serializer BarSerializer but instead was FooSerializer"
+        expect {
+          expect(subject).to belong_to(:foo).as(:bar).serialized_with(BarSerializer)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:foo).serialized_with(BarSerializer).as(:bar)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:foo).serialized_with(BarSerializer).as(:bor)
+        }.to fail_with(failure_message)
+      end
+
+      it 'should fail a belong_to :foo as :bor expectation' do
+        failure_message = "expected #{ subject } 'belongs_to :foo' association to explicitly have key :bor but instead was :bar"
+        expect {
+          expect(subject).to belong_to(:foo).serialized_with(FooSerializer).as(:bor)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:foo).as(:bor).serialized_with(FooSerializer)
+        }.to fail_with(failure_message)
+        expect {
+          expect(subject).to belong_to(:foo).as(:bor).serialized_with(BarSerializer)
+        }.to fail_with(failure_message)
+      end
+    end
+  end
 end

spec/active_model_serializers_matchers_spec.rb

@@ -1,6 +1,15 @@
 require 'spec_helper'
 
 describe ActiveModelSerializersMatchers do
+  describe '#belong_to' do
+    it 'returns a new AssociationMatcher of type :belongs_to' do
+      expect(described_class::AssociationMatcher)
+        .to receive(:new).with(:association_root, :belongs_to)
+        .and_call_original
+      expect(belong_to(:association_root))
+        .to be_a described_class::AssociationMatcher
+    end
+  end
 
   describe '#have_many' do
     it 'returns a new AssociationMatcher of type :has_many' do

spec/support/shared_examples.rb

@@ -169,3 +169,83 @@
     }.to fail_with("expected #{ subject } 'has_many :foos' association to explicitly have embed key :bar_external_id but instead was :foo_external_id")
   end
 end
+
+shared_examples 'it belongs_to :foo' do
+  it 'should pass a belong_to :foo expectation' do
+    expectation = belong_to(:foo)
+    expect(subject).to expectation
+    expect(expectation.description).to eq('belong to :foo')
+  end
+
+  it 'should fail a belong_to :fuu expectation' do
+    expect {
+      expect(subject).to belong_to(:fuu)
+    }.to fail_with("expected #{ subject } to define a 'belongs_to :fuu' association")
+  end
+end
+
+shared_examples 'it belongs_to :foo and no key' do
+  it 'should fail a belong_to :foo as :bar expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).as(:bar)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have key :bar but instead has none")
+  end
+end
+
+shared_examples 'it belongs_to :foo and no serializer' do
+  it 'should fail a belong_to :foo serialized with FooSerializer expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).serialized_with(FooSerializer)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have serializer FooSerializer but instead has none")
+  end
+end
+
+shared_examples 'it belongs_to :foo and no embed_key' do
+  it 'should fail a belong_to :foo with_embed_key :foo_external_id expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).with_embed_key(:foo_external_id)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have embed key :foo_external_id but instead has none")
+  end
+end
+
+shared_examples 'it belongs_to :foo with key :bar' do
+  it 'should pass a belong_to :foo as :bar expectation' do
+    expectation = belong_to(:foo).as(:bar)
+    expect(subject).to expectation
+    expect(expectation.description).to eq('belong to :foo as :bar')
+  end
+
+  it 'should fail a belong_to :foo as :bor expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).as(:bor)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have key :bor but instead was :bar")
+  end
+end
+
+shared_examples 'it belongs_to :foo with serializer FooSerializer' do
+  it 'should pass a belong_to :foo as :bar expectation' do
+    expectation = belong_to(:foo).serialized_with(FooSerializer)
+    expect(subject).to expectation
+    expect(expectation.description).to eq('belong to :foo serialized with FooSerializer')
+  end
+
+  it 'should fail a belong_to :foo serialized with FooSerializer expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).serialized_with(BarSerializer)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have serializer BarSerializer but instead was FooSerializer")
+  end
+end
+
+shared_examples 'it belongs_to :foo with embed_key :foo_external_id' do
+  it 'should pass a belong_to :foo with embed key :foo_external_id' do
+    expectation = belong_to(:foo).with_embed_key(:foo_external_id)
+    expect(subject).to expectation
+    expect(expectation.description).to eq('belong to :foo with embed key :foo_external_id')
+  end
+
+  it 'should fail a belong_to :foo with embed key :bar_external_id expectation' do
+    expect {
+      expect(subject).to belong_to(:foo).with_embed_key(:bar_external_id)
+    }.to fail_with("expected #{ subject } 'belongs_to :foo' association to explicitly have embed key :bar_external_id but instead was :foo_external_id")
+  end
+end