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