Added Cop to blacklist polymorphic associations

One should really use a separate table instead of using polymorphic
associations.

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11168 for
more information.

2 files changed, 35 insertions, 2 deletions

diff --git a/spec/rubocop/cop/activerecord_serialize_spec.rb b/spec/rubocop/cop/activerecord_serialize_spec.rb
index a303b16d264..5bd7e5fa926 100644
--- a/spec/rubocop/cop/activerecord_serialize_spec.rb
+++ b/spec/rubocop/cop/activerecord_serialize_spec.rb
@@ -10,7 +10,7 @@ describe RuboCop::Cop::ActiverecordSerialize do
 
   context 'inside the app/models directory' do
     it 'registers an offense when serialize is used' do
-      allow(cop).to receive(:in_models?).and_return(true)
+      allow(cop).to receive(:in_model?).and_return(true)
 
       inspect_source(cop, 'serialize :foo')
 
@@ -23,7 +23,7 @@ describe RuboCop::Cop::ActiverecordSerialize do
 
   context 'outside the app/models directory' do
     it 'does nothing' do
-      allow(cop).to receive(:in_models?).and_return(false)
+      allow(cop).to receive(:in_model?).and_return(false)
 
       inspect_source(cop, 'serialize :foo')
 
diff --git a/spec/rubocop/cop/polymorphic_associations_spec.rb b/spec/rubocop/cop/polymorphic_associations_spec.rb
new file mode 100644
index 00000000000..49959aa6419
--- /dev/null
+++ b/spec/rubocop/cop/polymorphic_associations_spec.rb
@@ -0,0 +1,33 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/polymorphic_associations'
+
+describe RuboCop::Cop::PolymorphicAssociations do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  context 'inside the app/models directory' do
+    it 'registers an offense when polymorphic: true is used' do
+      allow(cop).to receive(:in_model?).and_return(true)
+
+      inspect_source(cop, 'belongs_to :foo, polymorphic: true')
+
+      aggregate_failures do
+        expect(cop.offenses.size).to eq(1)
+        expect(cop.offenses.map(&:line)).to eq([1])
+      end
+    end
+  end
+
+  context 'outside the app/models directory' do
+    it 'does nothing' do
+      allow(cop).to receive(:in_model?).and_return(false)
+
+      inspect_source(cop, 'belongs_to :foo, polymorphic: true')
+
+      expect(cop.offenses).to be_empty
+    end
+  end
+end