debian-mirror-gitlab/spec/lib/gitlab/graphql/lazy_spec.rb
2021-01-29 00:20:46 +05:30

96 lines
2.3 KiB
Ruby

# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Gitlab::Graphql::Lazy do
def load(key)
BatchLoader.for(key).batch do |keys, loader|
keys.each { |x| loader.call(x, x * x) }
end
end
let(:value) { double(x: 1) }
describe '#force' do
subject { described_class.new { value.x } }
it 'can extract the value' do
expect(subject.force).to be 1
end
it 'can derive new lazy values' do
expect(subject.then { |x| x + 2 }.force).to be 3
end
it 'only evaluates once' do
expect(value).to receive(:x).once
expect(subject.force).to eq(subject.force)
end
it 'deals with nested laziness' do
expect(described_class.new { load(10) }.force).to eq(100)
expect(described_class.new { described_class.new { 5 } }.force).to eq 5
end
end
describe '.with_value' do
let(:inner) { described_class.new { value.x } }
subject { described_class.with_value(inner) { |x| x.to_s } }
it 'defers the application of a block to a value' do
expect(value).not_to receive(:x)
expect(subject).to be_an_instance_of(described_class)
end
it 'evaluates to the application of the block to the value' do
expect(value).to receive(:x).once
expect(subject.force).to eq(inner.force.to_s)
end
end
describe '.force' do
context 'when given a plain value' do
subject { described_class.force(1) }
it 'unwraps the value' do
expect(subject).to be 1
end
end
context 'when given a wrapped lazy value' do
subject { described_class.force(described_class.new { 2 }) }
it 'unwraps the value' do
expect(subject).to be 2
end
end
context 'when the value is from a batchloader' do
subject { described_class.force(load(3)) }
it 'syncs the value' do
expect(subject).to be 9
end
end
context 'when the value is a GraphQL lazy' do
subject { described_class.force(GitlabSchema.after_lazy(load(3)) { |x| x + 1 } ) }
it 'forces the evaluation' do
expect(subject).to be 10
end
end
context 'when the value is a promise' do
subject { described_class.force(::Concurrent::Promise.new { 4 }) }
it 'executes the promise and waits for the value' do
expect(subject).to be 4
end
end
end
end