1 files changed, 70 insertions, 0 deletions
diff --git a/spec/lib/gitlab/utils/lazy_attributes_spec.rb b/spec/lib/gitlab/utils/lazy_attributes_spec.rb
new file mode 100644
index 00000000000..c0005c194c4
--- /dev/null
+++ b/spec/lib/gitlab/utils/lazy_attributes_spec.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+require 'fast_spec_helper'
+require 'active_support/concern'
+
+describe Gitlab::Utils::LazyAttributes do
+  subject(:klass) do
+    Class.new do
+      include Gitlab::Utils::LazyAttributes
+
+      lazy_attr_reader :number, type: Numeric
+      lazy_attr_reader :reader_1, :reader_2
+      lazy_attr_accessor :incorrect_type, :string_attribute, :accessor_2, type: String
+
+      def initialize
+        @number = -> { 1 }
+        @reader_1, @reader_2 = 'reader_1', -> { 'reader_2' }
+        @incorrect_type, @accessor_2 = -> { :incorrect_type }, -> { 'accessor_2' }
+      end
+    end
+  end
+
+  context 'class methods' do
+    it { is_expected.to respond_to(:lazy_attr_reader, :lazy_attr_accessor) }
+    it { is_expected.not_to respond_to(:define_lazy_reader, :define_lazy_writer) }
+  end
+
+  context 'instance methods' do
+    subject(:instance) { klass.new }
+
+    it do
+      is_expected.to respond_to(:number, :reader_1, :reader_2, :incorrect_type,
+                                :incorrect_type=, :accessor_2, :accessor_2=,
+                                :string_attribute, :string_attribute=)
+    end
+
+    context 'reading attributes' do
+      it 'returns the correct values for procs', :aggregate_failures do
+        expect(instance.number).to eq(1)
+        expect(instance.reader_2).to eq('reader_2')
+        expect(instance.accessor_2).to eq('accessor_2')
+      end
+
+      it 'does not return the value if the type did not match what was specified' do
+        expect(instance.incorrect_type).to be_nil
+      end
+
+      it 'only calls the block once even if it returned `nil`', :aggregate_failures do
+        expect(instance.instance_variable_get('@number')).to receive(:call).once.and_call_original
+        expect(instance.instance_variable_get('@accessor_2')).to receive(:call).once.and_call_original
+        expect(instance.instance_variable_get('@incorrect_type')).to receive(:call).once.and_call_original
+
+        2.times do
+          instance.number
+          instance.incorrect_type
+          instance.accessor_2
+        end
+      end
+    end
+
+    context 'writing attributes' do
+      it 'sets the correct values', :aggregate_failures do
+        instance.string_attribute = -> { 'updated 1' }
+        instance.accessor_2 = nil
+
+        expect(instance.string_attribute).to eq('updated 1')
+        expect(instance.accessor_2).to be_nil
+      end
+    end
+  end
+end