gitlab-org--gitlab-foss/spec/lib/gitlab/utils/strong_memoize_spec.rb

112 lines
2.7 KiB
Ruby

# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Gitlab::Utils::StrongMemoize do
let(:klass) do
struct = Struct.new(:value) do
def method_name
strong_memoize(:method_name) do
trace << value
value
end
end
def trace
@trace ||= []
end
end
struct.include(described_class)
struct
end
subject(:object) { klass.new(value) }
shared_examples 'caching the value' do
it 'only calls the block once' do
value0 = object.method_name
value1 = object.method_name
expect(value0).to eq(value)
expect(value1).to eq(value)
expect(object.trace).to contain_exactly(value)
end
it 'returns and defines the instance variable for the exact value' do
returned_value = object.method_name
memoized_value = object.instance_variable_get(:@method_name)
expect(returned_value).to eql(value)
expect(memoized_value).to eql(value)
end
end
describe '#strong_memoize' do
[nil, false, true, 'value', 0, [0]].each do |value|
context "with value #{value}" do
let(:value) { value }
it_behaves_like 'caching the value'
it 'raises exception for invalid key' do
expect { object.strong_memoize(10) { 20 } }.to raise_error /Invalid type of '10'/
end
end
end
context "memory allocation", type: :benchmark do
let(:value) { 'aaa' }
before do
object.method_name # warmup
end
[:method_name, "method_name"].each do |argument|
context "for #{argument.class}" do
it 'does allocate exactly one string when fetching value' do
expect do
object.strong_memoize(argument) { 10 }
end.to perform_allocation(1)
end
it 'does allocate exactly one string when storing value' do
object.clear_memoization(:method_name) # clear to force set
expect do
object.strong_memoize(argument) { 10 }
end.to perform_allocation(1)
end
end
end
end
end
describe '#strong_memoized?' do
let(:value) { :anything }
subject { object.strong_memoized?(:method_name) }
it 'returns false if the value is uncached' do
is_expected.to be(false)
end
it 'returns true if the value is cached' do
object.method_name
is_expected.to be(true)
end
end
describe '#clear_memoization' do
let(:value) { 'mepmep' }
it 'removes the instance variable' do
object.method_name
object.clear_memoization(:method_name)
expect(object.instance_variable_defined?(:@method_name)).to be(false)
end
end
end