forked from ruby-concurrency/concurrent-ruby
/
promise_spec.rb
697 lines (539 loc) · 20.2 KB
/
promise_spec.rb
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require_relative 'ivar_shared'
require_relative 'thread_arguments_shared'
module Concurrent
RSpec.describe Promise do
let!(:value) { 10 }
let(:executor) { SimpleExecutorService.new }
let(:empty_root) { Promise.new(executor: executor){ nil } }
let!(:fulfilled_value) { 10 }
let!(:rejected_reason) { StandardError.new('mojo jojo') }
let(:pending_subject) do
executor = Concurrent::SingleThreadExecutor.new
executor.post{ sleep(5) }
Promise.execute(executor: executor){ fulfilled_value }
end
let(:fulfilled_subject) do
Promise.new(executor: :immediate){ fulfilled_value }.execute
end
let(:rejected_subject) do
Promise.new(executor: :immediate){ raise rejected_reason }.execute
end
it_should_behave_like :ivar do
subject{ Promise.new(executor: :immediate){ value } }
def dereferenceable_subject(value, opts = {})
opts = opts.merge(executor: executor)
Promise.new(opts){ value }.execute.tap{ sleep(0.1) }
end
def dereferenceable_observable(opts = {})
opts = opts.merge(executor: executor)
Promise.new(opts){ 'value' }
end
def execute_dereferenceable(subject)
subject.execute
sleep(0.1)
end
def trigger_observable(observable)
observable.execute
sleep(0.1)
end
end
it_should_behave_like :thread_arguments do
def get_ivar_from_no_args
Concurrent::Promise.execute{|*args| args }
end
def get_ivar_from_args(opts)
Concurrent::Promise.execute(opts){|*args| args }
end
end
context 'initializers' do
describe '.fulfill' do
subject { Promise.fulfill(10) }
it 'should return a Promise' do
expect(subject).to be_a Promise
end
it 'should return a fulfilled Promise' do
expect(subject).to be_fulfilled
end
it 'should return a Promise with set value' do
expect(subject.value).to eq 10
end
end
describe '.reject' do
let(:reason) { ArgumentError.new }
subject { Promise.reject(reason) }
it 'should return a Promise' do
expect(subject).to be_a Promise
end
it 'should return a rejected Promise' do
expect(subject).to be_rejected
end
it 'should return a Promise with set reason' do
expect(subject.reason).to be reason
end
end
describe '.new' do
it 'should return an unscheduled Promise' do
p = Promise.new(executor: :immediate){ nil }
expect(p).to be_unscheduled
end
end
describe '.execute' do
it 'creates a new Promise' do
p = Promise.execute(executor: :immediate){ nil }
expect(p).to be_a(Promise)
end
it 'passes the block to the new Promise' do
p = Promise.execute(executor: :immediate){ 20 }
expect(p.value).to eq 20
end
it 'calls #execute on the new Promise' do
p = double('promise')
allow(Promise).to receive(:new).with(any_args).and_return(p)
expect(p).to receive(:execute).with(no_args)
Promise.execute(executor: :immediate){ nil }
end
end
end
context '#execute' do
context 'unscheduled' do
it 'sets the promise to :pending' do
start_latch = CountDownLatch.new
end_latch = CountDownLatch.new
p = Promise.new(executor: executor) do
start_latch.count_down
end_latch.wait(1)
end
start_latch.wait(1)
p.execute
expect(p).to be_pending
end_latch.count_down
end
it 'posts the block given in construction' do
executor = ImmediateExecutor.new
expect(executor).to receive(:post).with(any_args).and_call_original
Promise.new(executor: executor){ nil }.execute
end
end
context 'pending' do
it 'sets the promise to :pending' do
latch = CountDownLatch.new
p = Promise.new{ latch.wait(1) }.execute
expect(p).to be_pending
latch.count_down
end
it 'does not post again' do
executor = SimpleExecutorService.new
expect(executor).to receive(:post).with(any_args).once
latch = CountDownLatch.new
p = Promise.new(executor: executor){ latch.wait(1) }.execute
10.times { p.execute }
latch.count_down
end
end
describe 'with children' do
let(:start_latch) { CountDownLatch.new(4) }
let(:end_latch) { CountDownLatch.new(1) }
let(:root) { Promise.new(executor: executor){ start_latch.count_down; end_latch.wait(5) } }
let(:c1) { root.then { start_latch.count_down; end_latch.wait(5) } }
let(:c2) { root.then { start_latch.count_down; end_latch.wait(5) } }
let(:c2_1) { c2.then { start_latch.count_down; end_latch.wait(5) } }
context 'when called on the root' do
it 'should set all promises to :pending' do
root.execute
start_latch.wait(1)
[root, c1, c2, c2_1].each { |p| expect(p).to be_pending }
end_latch.count_down
end
end
context 'when called on a child' do
it 'should set all promises to :pending' do
c2_1.execute
start_latch.wait(1)
[root, c1, c2, c2_1].each { |p| expect(p).to be_pending }
end_latch.count_down
end
end
end
end
describe '#then' do
it 'returns a new promise when a block is passed' do
child = empty_root.then { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
it 'returns a new promise when a rescuer is passed' do
child = empty_root.then(Proc.new{})
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
it 'returns a new promise when a block and rescuer are passed' do
child = empty_root.then(Proc.new{}) { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
it 'returns a new promise when a block, rescuer and executor are passed' do
new_executor = Concurrent::SingleThreadExecutor.new
child = empty_root.then(Proc.new{}, new_executor) { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
expect(child.instance_variable_get(:@executor)).to be(new_executor)
end
it 'should have block or rescuers' do
expect { empty_root.then }.to raise_error(ArgumentError)
end
context 'unscheduled' do
let(:p1) { Promise.new(executor: executor){nil} }
let(:child) { p1.then{} }
it 'returns a new promise' do
expect(child).to be_a Promise
expect(p1).not_to be child
end
it 'returns an unscheduled promise' do
expect(child).to be_unscheduled
end
end
context 'pending' do
let(:child) { pending_subject.then{} }
it 'returns a new promise' do
expect(child).to be_a Promise
expect(pending_subject).not_to be child
end
it 'returns a pending promise' do
expect(child).to be_pending
end
end
context 'fulfilled' do
it 'returns a new Promise' do
p1 = fulfilled_subject
p2 = p1.then{}
expect(p2).to be_a(Promise)
expect(p1).not_to eq p2
end
it 'notifies fulfillment to new child' do
child = fulfilled_subject.then(Proc.new{ 7 }) { |v| v + 5 }
expect(child.value).to eq fulfilled_value + 5
end
end
context 'rejected' do
it 'returns a new Promise when :rejected' do
p1 = rejected_subject
p2 = p1.then{}
expect(p2).to be_a(Promise)
expect(p1).not_to eq p2
end
it 'notifies rejection to new child' do
child = rejected_subject.then(Proc.new{ 7 }) { |v| v + 5 }
expect(child.value).to eq 7
end
end
it 'can be called more than once' do
p = pending_subject
p1 = p.then{}
p2 = p.then{}
expect(p1).not_to be p2
end
end
describe 'on_success' do
it 'should have a block' do
expect { empty_root.on_success }.to raise_error(ArgumentError)
end
it 'returns a new promise' do
child = empty_root.on_success { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
end
context '#rescue' do
it 'returns a new promise' do
child = empty_root.rescue { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
end
describe '#flat_map' do
it 'returns a promise' do
child = empty_root.flat_map { nil }
expect(child).to be_a Promise
expect(child).not_to be empty_root
end
it 'succeeds if both promises succeed' do
child = Promise.new(executor: :immediate) { 1 }.
flat_map { |v| Promise.new(executor: :immediate) { v + 10 } }.execute.wait
expect(child.value!).to eq(11)
end
it 'fails if the left promise fails' do
child = Promise.new(executor: :immediate) { fail }.
flat_map { |v| Promise.new(executor: :immediate) { v + 10 } }.execute.wait
expect(child).to be_rejected
end
it 'fails if the right promise fails' do
child = Promise.new(executor: :immediate) { 1 }.
flat_map { |v| Promise.new(executor: :immediate) { fail } }.execute.wait
expect(child).to be_rejected
end
it 'fails if the generating block fails' do
child = Promise.new(executor: :immediate) { }.flat_map { fail }.execute.wait
expect(child).to be_rejected
end
end
describe '#zip' do
let(:promise1) { Promise.new(executor: :immediate) { 1 } }
let(:promise2) { Promise.new(executor: :immediate) { 2 } }
let(:promise3) { Promise.new(executor: :immediate) { [3] } }
it 'yields the results as an array' do
composite = promise1.zip(promise2, promise3).execute.wait
expect(composite.value).to eq([1, 2, [3]])
end
it 'fails if one component fails' do
composite = promise1.zip(promise2, rejected_subject, promise3).execute.wait
expect(composite).to be_rejected
end
it 'preserves ordering of the executed promises' do
10.times do
latch1 = CountDownLatch.new
latch2 = CountDownLatch.new
executor = SimpleExecutorService.new
p1 = Concurrent::Promise.execute(executor: executor) { latch1.wait; 'one' }
p2 = Concurrent::Promise.execute(executor: executor) { latch2.wait; 'two' }
p3 = Concurrent::Promise.execute(executor: executor) { 'three' }
latch1.count_down
latch2.count_down
result = Concurrent::Promise.zip(p1, p2, p3).value!
expect(result).to eq(['one', 'two', 'three'])
end
end
end
describe '.zip' do
let(:promise1) { Promise.new(executor: :immediate) { 1 } }
let(:promise2) { Promise.new(executor: :immediate) { 2 } }
let(:promise3) { Promise.new(executor: :immediate) { [3] } }
it 'yields the results as an array' do
composite = Promise.zip(promise1, promise2, promise3).execute.wait
expect(composite.value).to eq([1, 2, [3]])
end
it 'fails if one component fails' do
composite = Promise.zip(promise1, promise2, rejected_subject, promise3).execute.wait
expect(composite).to be_rejected
end
it 'preserves ordering of the executed promises' do
promise1 = Promise.execute do
# resolves after the second promise
sleep 0.2
'one'
end
promise2 = Promise.execute do
sleep 0.1
'two'
end
promise3 = Promise.execute do
'three'
end
result = Promise.zip(promise1, promise2, promise3).value
expect(result).to eql(['one', 'two', 'three'])
end
end
describe 'aggregators' do
let(:promise1) { Promise.new(executor: :immediate) { 1 } }
let(:promise2) { Promise.new(executor: :immediate) { 2 } }
let(:promise3) { Promise.new(executor: :immediate) { [3] } }
describe '.all?' do
it 'returns a new Promise' do
composite = Promise.all?(promise1, promise2, promise3).execute
expect(composite).to be_a Concurrent::Promise
end
it 'does not execute the returned Promise' do
composite = Promise.all?(promise1, promise2, promise3)
expect(composite).to be_unscheduled
end
it 'executes the #then condition when all components succeed' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.all?(promise1, promise2, promise3).
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq 1
end
it 'executes the #then condition when no promises are given' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.all?.
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq 1
end
it 'executes the #rescue handler if even one component fails' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.all?(promise1, promise2, rejected_subject, promise3).
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq(-1)
end
end
describe '.any?' do
it 'returns a new Promise' do
composite = Promise.any?(promise1, promise2, promise3).execute
expect(composite).to be_a Concurrent::Promise
end
it 'does not execute the returned Promise' do
composite = Promise.any?(promise1, promise2, promise3)
expect(composite).to be_unscheduled
end
it 'executes the #then condition when any components succeed' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.any?(promise1, promise2, rejected_subject, promise3).
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq 1
end
it 'executes the #then condition when no promises are given' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.any?.
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq 1
end
it 'executes the #rescue handler if all componenst fail' do
counter = Concurrent::AtomicFixnum.new(0)
latch = Concurrent::CountDownLatch.new(1)
Promise.any?(rejected_subject, rejected_subject, rejected_subject, rejected_subject).
then { counter.up; latch.count_down }.
rescue { counter.down; latch.count_down }.
execute
latch.wait(1)
expect(counter.value).to eq(-1)
end
end
end
context 'fulfillment' do
context '#set' do
it '#can only be called on the root promise' do
root = Promise.new{ :foo }
child = root.then{ :bar }
expect { child.set('foo') }.to raise_error PromiseExecutionError
expect { root.set('foo') }.not_to raise_error
end
it 'triggers children' do
expected = nil
root = Promise.new(executor: :immediate){ nil }
root.then{ |result| expected = result }
root.set(20)
expect(expected).to eq 20
end
it 'can be called with a block' do
p = Promise.new(executor: :immediate)
ch = p.then(&:to_s)
p.set { :value }
expect(p.value).to eq :value
expect(p.state).to eq :fulfilled
expect(ch.value).to eq 'value'
expect(ch.state).to eq :fulfilled
end
end
context '#fail' do
it 'can only be called on the root promise' do
root = Promise.new{ :foo }
child = root.then{ :bar }
expect { child.fail }.to raise_error PromiseExecutionError
expect { root.fail }.not_to raise_error
end
it 'rejects children' do
expected = nil
root = Promise.new(executor: :immediate)
root.then(Proc.new{ |reason| expected = reason })
root.fail(ArgumentError.new('simulated error'))
expect(expected).to be_a ArgumentError
end
end
it 'passes the result of each block to all its children' do
expected = nil
Promise.new(executor: :immediate){ 20 }.then{ |result| expected = result }.execute
expect(expected).to eq 20
end
it 'sets the promise value to the result if its block' do
root = Promise.new(executor: :immediate){ 20 }
p = root.then{ |result| result * 2}.execute
expect(root.value).to eq 20
expect(p.value).to eq 40
end
it 'sets the promise state to :fulfilled if the block completes' do
p = Promise.new(executor: :immediate){ 10 * 2 }.then{|result| result * 2}.execute
expect(p).to be_fulfilled
end
it 'passes the last result through when a promise has no block' do
expected = nil
Promise.new(executor: :immediate){ 20 }.then(Proc.new{}).then{|result| expected = result}.execute
expect(expected).to eq 20
end
it 'uses result as fulfillment value when a promise has no block' do
p = Promise.new(executor: :immediate){ 20 }.then(Proc.new{}).execute
expect(p.value).to eq 20
end
it 'can manage long chain' do
root = Promise.new(executor: :immediate){ 20 }
p1 = root.then { |b| b * 3 }
p2 = root.then { |c| c + 2 }
p3 = p1.then { |d| d + 7 }
root.execute
expect(root.value).to eq 20
expect(p1.value).to eq 60
expect(p2.value).to eq 22
expect(p3.value).to eq 67
end
end
context 'rejection' do
it 'passes the reason to all its children' do
expected = nil
handler = proc { |reason| expected = reason }
Promise.new(executor: :immediate){ raise ArgumentError }.then(handler).execute
expect(expected).to be_a ArgumentError
end
it 'sets the promise value to the result if its block' do
root = Promise.new(executor: :immediate){ raise ArgumentError }
p = root.then(Proc.new{ |reason| 42 }).execute
expect(p.value).to eq 42
end
it 'sets the promise state to :rejected if the block completes' do
p = Promise.new(executor: :immediate){ raise ArgumentError }.execute
expect(p).to be_rejected
end
it 'uses reason as rejection reason when a promise has no rescue callable' do
p = Promise.new(executor: :immediate){ raise ArgumentError }.then{ |val| val }.execute
expect(p).to be_rejected
expect(p.reason).to be_a ArgumentError
end
it 'rejects on Exception' do
p = Promise.new(executor: :immediate){ raise Exception }.execute
expect(p).to be_rejected
end
end
context 'aliases' do
it 'aliases #realized? for #fulfilled?' do
expect(fulfilled_subject).to be_realized
end
it 'aliases #deref for #value' do
expect(fulfilled_subject.deref).to eq fulfilled_value
end
it 'aliases #catch for #rescue' do
child = rejected_subject.catch { 7 }
expect(child.value).to eq 7
end
it 'aliases #on_error for #rescue' do
child = rejected_subject.on_error { 7 }
expect(child.value).to eq 7
end
end
end
end