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Testing Statistical Counter Operations in Resque

This test suite validates the functionality of Resque::Stat class, which handles statistical operations in the Resque job queue system. The tests ensure proper handling of statistical counters, including increment, decrement, and data store management.

Test Coverage Overview

The test suite provides comprehensive coverage of Resque’s statistical operations functionality.

Core statistical operations testing including get, increment, and decrement
Data store management and interaction verification
Deprecation warning validation for legacy methods
Counter manipulation using both standard and operator methods

Implementation Analysis

The testing approach utilizes RSpec’s describe/it blocks with a DummyStatStore implementation for isolated testing. The suite employs before/after hooks for test environment setup and cleanup, ensuring consistent test state.

Mock data store implementation for controlled testing
State management through setup/teardown hooks
Assertion-based verification of counter operations

Technical Details

Testing Framework: RSpec
Test Dependencies: test_helper
Mock Objects: DummyStatStore class
Assertion Methods: assert_equal, assert_output
Setup/Teardown: before/after blocks for state management

Best Practices Demonstrated

The test suite demonstrates several testing best practices for Ruby unit testing.

Isolation of tests using mock objects
Proper test setup and teardown
Comprehensive coverage of edge cases
Clear test naming and organization
Verification of deprecation warnings

resque/resque

test/stat_test.rb

            
require 'test_helper'

describe "Resque::Stat" do
  class DummyStatStore
    def initialize
      @stat = Hash.new(0)
    end

    def stat(stat)
      @stat[stat]
    end

    def increment_stat(stat, by = 1, redis: nil)
      @stat[stat] += by
    end

    def decrement_stat(stat, by)
      @stat[stat] -= by
    end

    def clear_stat(stat, redis: nil)
      @stat[stat] = 0
    end
  end

  before do
    @original_data_store = Resque::Stat.data_store
    @dummy_data_store = DummyStatStore.new
    Resque::Stat.data_store = @dummy_data_store
  end

  after do
    Resque::Stat.data_store = @original_data_store
  end

  it '#redis show deprecation warning' do
    assert_output(nil, /\[Resque\] \[Deprecation\]/ ) do
      assert_equal @dummy_data_store, Resque::Stat.redis
    end
  end

  it '#redis returns data_store' do
    assert_equal @dummy_data_store, Resque::Stat.data_store
  end

  it "#get" do
    assert_equal 0, Resque::Stat.get('hello')
  end

  it "#[]" do
    assert_equal 0, Resque::Stat['hello']
  end

  it "#incr" do
    assert_equal 2, Resque::Stat.incr('hello', 2)
    assert_equal 2, Resque::Stat['hello']
  end

  it "#<<" do
    assert_equal 1, Resque::Stat << 'hello'
    assert_equal 1, Resque::Stat['hello']
  end

  it "#decr" do
    assert_equal 2, Resque::Stat.incr('hello', 2)
    assert_equal 2, Resque::Stat['hello']

    assert_equal 0, Resque::Stat.decr('hello', 2)
    assert_equal 0, Resque::Stat['hello']
  end

  it "#>>" do
    assert_equal 2, Resque::Stat.incr('hello', 2)
    assert_equal 2, Resque::Stat['hello']

    assert_equal 1, Resque::Stat >> 'hello'
    assert_equal 1, Resque::Stat['hello']
  end

  it '#clear' do
    assert_equal 2, Resque::Stat.incr('hello', 2)
    assert_equal 2, Resque::Stat['hello']

    Resque::Stat.clear('hello')

    assert_equal 0, Resque::Stat['hello']
  end
end