Add specs for #cached_attr_reader and cached_attr_time_reader

spec/models/concerns/redis_cacheable_spec.rb

 require 'spec_helper'
 
 describe RedisCacheable do
-  let(:model) { double }
+  let(:model) do
+    Struct.new(:id, :attributes) do
+      def read_attribute(attribute)
+        attributes[attribute]
+      end
+    end
+  end
+
+  let(:payload) { { name: 'value' } }
+  let(:instance) { model.new(1, payload) }
+  let(:cache_key) { instance.__send__(:cache_attribute_key) }
 
   before do
-    model.extend(described_class)
-    allow(model).to receive(:cache_attribute_key).and_return('key')
+    model.include(described_class)
   end
 
   describe '#cached_attribute' do
-    let(:payload) { { attribute: 'value' } }
-
-    subject { model.cached_attribute(payload.keys.first) }
+    subject { instance.cached_attribute(payload.keys.first) }
 
     it 'gets the cache attribute' do
       Gitlab::Redis::SharedState.with do |redis|
-        expect(redis).to receive(:get).with('key')
+        expect(redis).to receive(:get).with(cache_key)
           .and_return(payload.to_json)
       end
 
@@ -24,16 +31,68 @@ describe RedisCacheable do
   end
 
   describe '#cache_attributes' do
-    let(:values) { { name: 'new_name' } }
-
-    subject { model.cache_attributes(values) }
+    subject { instance.cache_attributes(payload) }
 
     it 'sets the cache attributes' do
       Gitlab::Redis::SharedState.with do |redis|
-        expect(redis).to receive(:set).with('key', values.to_json, anything)
+        expect(redis).to receive(:set).with(cache_key, payload.to_json, anything)
       end
 
       subject
     end
   end
+
+  describe '#cached_attr_reader' do
+    subject { instance.name }
+
+    before do
+      model.cached_attr_reader(:name)
+    end
+
+    context 'when there is no cached value' do
+      it 'checks the cached value first then reads the attribute' do
+        expect(instance).to receive(:cached_attribute).and_return(nil)
+        expect(instance).to receive(:read_attribute).and_return(payload[:name])
+
+        expect(subject).to eq(payload[:name])
+      end
+    end
+
+    context 'when there is a cached value' do
+      it 'reads the cached value' do
+        expect(instance).to receive(:cached_attribute).and_return(payload[:name])
+        expect(instance).not_to receive(:read_attribute)
+
+        expect(subject).to eq(payload[:name])
+      end
+    end
+  end
+
+  describe '#cached_attr_time_reader' do
+    subject { instance.time }
+
+    before do
+      model.cached_attr_time_reader(:time)
+    end
+
+    context 'when there is no cached value' do
+      it 'checks the cached value first then reads the attribute' do
+        expect(instance).to receive(:cached_attribute).and_return(nil)
+        expect(instance).to receive(:read_attribute).and_return(Time.zone.now)
+
+        expect(subject).to be_instance_of(ActiveSupport::TimeWithZone)
+        expect(subject).to be_within(1.minute).of(Time.zone.now)
+      end
+    end
+
+    context 'when there is a cached value' do
+      it 'reads the cached value' do
+        expect(instance).to receive(:cached_attribute).and_return(Time.zone.now.to_s)
+        expect(instance).not_to receive(:read_attribute)
+
+        expect(subject).to be_instance_of(ActiveSupport::TimeWithZone)
+        expect(subject).to be_within(1.minute).of(Time.zone.now)
+      end
+    end
+  end
 end