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Testing Deprecation Utility Functions in video.js

This test suite validates the deprecation utility functions in Video.js, ensuring proper warning message handling and function behavior preservation. The tests verify both simple deprecation notices and major version deprecation warnings.

Test Coverage Overview

The test suite provides comprehensive coverage of the deprecate.js utility functions, focusing on argument passing, context preservation, and warning message generation.

Tests function argument pass-through and return values
Verifies ‘this’ context binding
Ensures warning messages are logged only once
Validates major version deprecation message formatting

Implementation Analysis

The testing approach utilizes QUnit’s module and test structure with sinon for spy functionality. The implementation uses beforeEach/afterEach hooks to manage console mocking.

Tests are organized into nested modules for different deprecation types, using sinon spies to verify console interaction patterns and QUnit assertions to validate function behavior.

Technical Details

Testing Framework: QUnit
Mocking Library: Sinon.js
Environment: Browser (window object)
Test Setup: Console method replacement
Assertion Types: deepEqual, strictEqual, ok

Best Practices Demonstrated

The test suite exemplifies strong testing practices through isolated console mocking, proper cleanup in afterEach hooks, and comprehensive edge case coverage.

Proper test isolation through console mocking
Consistent cleanup of test environment
Multiple assertion types for thorough validation
Clear test case organization and naming

videojs/videoJs

test/unit/utils/deprecate.test.js

            
/* eslint-env qunit */
import window from 'global/window';
import sinon from 'sinon';
import {deprecate, deprecateForMajor} from '../../../src/js/utils/deprecate.js';

QUnit.module('utils/deprecate', {
  beforeEach() {

    // Back up the original console.
    this.originalConsole = window.console;

    // Replace the native console for testing. In IE8 `console.log` is not a
    // 'function' so sinon chokes on it when trying to spy:
    //   https://github.com/cjohansen/Sinon.JS/issues/386
    //
    // Instead we'll temporarily replace them with no-op functions
    window.console = {
      debug: sinon.spy(),
      info: sinon.spy(),
      log: sinon.spy(),
      warn: sinon.spy(),
      error: sinon.spy()
    };
  },
  afterEach() {

    // Restore the native/original console.
    window.console = this.originalConsole;
  }
}, function() {

  QUnit.module('deprecate');

  QUnit.test('should pass through arguments to a function and return expected value', function(assert) {
    assert.expect(1);

    const test = deprecate('test', (...args) => args);
    const result = test(1, 2, 3);

    assert.deepEqual(result, [1, 2, 3]);
  });

  QUnit.test('should maintain the correct "this" value', function(assert) {
    assert.expect(1);

    const that = {};
    const test = deprecate('test', function() {
      return this;
    }.bind(that));

    const result = test();

    assert.strictEqual(result, that, 'the "this" value was returned as the expected object');
  });

  QUnit.test('should log the specified message only once', function(assert) {
    assert.expect(2);

    const test = deprecate('test', function() {});

    test();
    test();
    test();

    assert.ok(window.console.warn.calledOnce);
    assert.deepEqual(window.console.warn.firstCall.args, ['VIDEOJS:', 'WARN:', 'test']);
  });

  QUnit.module('deprecateForMajor');

  QUnit.test('should pass through arguments to a function and return expected value', function(assert) {
    assert.expect(1);

    const test = deprecateForMajor(1, 'A', 'B', (...args) => args);
    const result = test(1, 2, 3);

    assert.deepEqual(result, [1, 2, 3]);
  });

  QUnit.test('should maintain the correct "this" value', function(assert) {
    assert.expect(1);

    const that = {};
    const test = deprecateForMajor(1, 'A', 'B', function() {
      return this;
    }.bind(that));

    const result = test();

    assert.strictEqual(result, that, 'the "this" value was returned as the expected object');
  });

  QUnit.test('should log the expected message only once', function(assert) {
    assert.expect(2);

    const test = deprecateForMajor(1, 'A', 'B', function() {});

    test();
    test();
    test();

    assert.ok(window.console.warn.calledOnce);
    assert.deepEqual(window.console.warn.firstCall.args, ['VIDEOJS:', 'WARN:', 'A is deprecated and will be removed in 1.0; please use B instead.']);
  });
});