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|
RSpec.shared_examples :observable do
let(:observer_set) do
subject.instance_variable_get(:@observers)
end
let(:observer_class) do
Class.new do
def initialize(&block)
@block = block
end
def update(*args)
@block.call(*args) if @block
end
end
end
let(:observer){ observer_class.new }
let!(:observer_func){ :notify }
let(:observer_with_func_class) do
Class.new do
def initialize(&block)
@block = block
end
def notify(*args)
@block.call(*args) if @block
end
end
end
let(:observer_with_func){ observer_with_func_class.new }
context '#add_observer' do
it 'adds an observer if called before first notification' do
expect(observer_set).to receive(:add_observer).with(any_args)
subject.add_observer(observer)
end
it 'adds an observer with :func if called before first notification' do
expect(observer_set).to receive(:add_observer).with(observer_with_func, :notify)
subject.add_observer(observer_with_func, observer_func)
end
it 'creates an observer from a block if called before first notification' do
block = proc{ nil }
expect(observer_set).to receive(:add_observer).with(any_args)
subject.add_observer(&block)
end
it 'raises an exception if not given an observer or a block' do
expect {
subject.add_observer
}.to raise_error(ArgumentError)
end
it 'raises an exception when given both an observer and a block' do
expect {
subject.add_observer(observer){ nil }
}.to raise_error(ArgumentError)
end
end
context '#delete_observer' do
it 'deletes the given observer if called before first notification' do
expect(subject.count_observers).to eq 0
subject.add_observer(observer)
expect(subject.count_observers).to eq 1
subject.delete_observer(observer)
expect(subject.count_observers).to eq 0
end
it 'returns the removed observer if found in the observer set' do
subject.add_observer(observer)
expect(subject.delete_observer(observer)).to eq observer
end
it 'returns the given observer even when not found in the observer set' do
expect(subject.delete_observer(observer)).to eq observer
end
end
context '#delete_observers' do
it 'deletes all observers when called before first notification' do
5.times{ subject.add_observer(observer_class.new) }
expect(subject.count_observers).to eq 5
subject.delete_observers
expect(subject.count_observers).to eq 0
end
it 'returns self' do
expect(subject.delete_observers).to eq subject
end
end
context '#count_observers' do
it 'returns zero for a new observable object' do
expect(subject.count_observers).to eq 0
end
it 'returns a count of registered observers if called before first notification' do
5.times{ subject.add_observer(observer_class.new) }
expect(subject.count_observers).to eq 5
end
it 'returns zero after #delete_observers has been called' do
5.times{ subject.add_observer(observer_class.new) }
subject.delete_observers
expect(subject.count_observers).to eq 0
end
end
context 'first notification' do
it 'calls the #update method on all observers without a specified :func' do
latch = Concurrent::CountDownLatch.new(5)
5.times do
subject.add_observer(observer_class.new{ latch.count_down })
end
trigger_observable(subject)
latch.wait(1)
expect(latch.count).to eq 0
end
it 'calls the appropriate function on all observers which specified a :func' do
latch = Concurrent::CountDownLatch.new(5)
5.times do
obs = observer_with_func_class.new{ latch.count_down }
subject.add_observer(obs, observer_func)
end
trigger_observable(subject)
latch.wait(1)
expect(latch.count).to eq 0
end
it 'calls the proc for all observers added as a block' do
latch = Concurrent::CountDownLatch.new(5)
5.times do
subject.add_observer{ latch.count_down }
end
trigger_observable(subject)
latch.wait(1)
expect(latch.count).to eq 0
end
it 'does not notify any observers removed with #delete_observer' do
latch = Concurrent::CountDownLatch.new(5)
obs = observer_class.new{ latch.count_down }
subject.add_observer(obs)
subject.delete_observer(obs)
trigger_observable(subject)
latch.wait(1)
expect(latch.count).to eq 5
end
it 'does not notify any observers after #delete_observers called' do
latch = Concurrent::CountDownLatch.new(5)
5.times do
subject.add_observer(observer_class.new{ latch.count_down })
end
subject.delete_observers
trigger_observable(subject)
latch.wait(1)
expect(latch.count).to eq 5
end
end
end
|
