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|
# frozen_string_literal: true
require 'spec_helper'
describe ReactiveCaching, :use_clean_rails_memory_store_caching do
include ExclusiveLeaseHelpers
include ReactiveCachingHelpers
class CacheTest
include ReactiveCaching
self.reactive_cache_key = ->(thing) { ["foo", thing.id] }
self.reactive_cache_lifetime = 5.minutes
self.reactive_cache_refresh_interval = 15.seconds
attr_reader :id
def initialize(id, &blk)
@id = id
@calculator = blk
end
def calculate_reactive_cache
@calculator.call
end
def result
with_reactive_cache do |data|
data
end
end
end
let(:calculation) { -> { 2 + 2 } }
let(:cache_key) { "foo:666" }
let(:instance) { CacheTest.new(666, &calculation) }
describe '#with_reactive_cache' do
before do
stub_reactive_cache
end
subject(:go!) { instance.result }
context 'when cache is empty' do
it { is_expected.to be_nil }
it 'enqueues a background worker to bootstrap the cache' do
expect(ReactiveCachingWorker).to receive(:perform_async).with(CacheTest, 666)
go!
end
it 'updates the cache lifespan' do
expect(reactive_cache_alive?(instance)).to be_falsy
go!
expect(reactive_cache_alive?(instance)).to be_truthy
end
end
context 'when the cache is full' do
before do
stub_reactive_cache(instance, 4)
end
it { is_expected.to eq(4) }
it 'does not enqueue a background worker' do
expect(ReactiveCachingWorker).not_to receive(:perform_async)
go!
end
it 'updates the cache lifespan' do
expect(Rails.cache).to receive(:write).with(alive_reactive_cache_key(instance), true, expires_in: anything)
go!
end
context 'and expired' do
before do
invalidate_reactive_cache(instance)
end
it { is_expected.to be_nil }
end
context 'when cache was invalidated' do
it 'refreshes cache' do
expect(ReactiveCachingWorker).to receive(:perform_async).with(CacheTest, 666)
instance.with_reactive_cache { raise described_class::InvalidateReactiveCache }
end
end
end
context 'when cache contains non-nil but blank value' do
before do
stub_reactive_cache(instance, false)
end
it { is_expected.to eq(false) }
end
end
describe '#clear_reactive_cache!' do
before do
stub_reactive_cache(instance, 4)
instance.clear_reactive_cache!
end
it { expect(instance.result).to be_nil }
it { expect(reactive_cache_alive?(instance)).to be_falsy }
end
describe '#exclusively_update_reactive_cache!' do
subject(:go!) { instance.exclusively_update_reactive_cache! }
context 'when the lease is free and lifetime is not exceeded' do
before do
stub_reactive_cache(instance, "preexisting")
end
it 'takes and releases the lease' do
expect_to_obtain_exclusive_lease(cache_key, 'uuid')
expect_to_cancel_exclusive_lease(cache_key, 'uuid')
go!
end
it 'caches the result of #calculate_reactive_cache' do
go!
expect(read_reactive_cache(instance)).to eq(calculation.call)
end
it "enqueues a repeat worker" do
expect_reactive_cache_update_queued(instance)
go!
end
it "calls a reactive_cache_updated only once if content did not change on subsequent update" do
expect(instance).to receive(:calculate_reactive_cache).twice
expect(instance).to receive(:reactive_cache_updated).once
2.times { instance.exclusively_update_reactive_cache! }
end
context 'and #calculate_reactive_cache raises an exception' do
before do
stub_reactive_cache(instance, "preexisting")
end
let(:calculation) { -> { raise "foo"} }
it 'leaves the cache untouched' do
expect { go! }.to raise_error("foo")
expect(read_reactive_cache(instance)).to eq("preexisting")
end
it 'enqueues a repeat worker' do
expect_reactive_cache_update_queued(instance)
expect { go! }.to raise_error("foo")
end
end
end
context 'when lifetime is exceeded' do
it 'skips the calculation' do
expect(instance).to receive(:calculate_reactive_cache).never
go!
end
end
context 'when the lease is already taken' do
it 'skips the calculation' do
stub_exclusive_lease_taken(cache_key)
expect(instance).to receive(:calculate_reactive_cache).never
go!
end
end
end
end
|
