zurvan/tests/BluebirdCompatibilityTests.js

A library for simulating time in Node.js

'use strict';
var TimeUnit = require('../TimeUnit');
var zurvan = require('../zurvan');
var assert = require('assert');
var bluebird = require('bluebird');

var FieldOverrider = require('../detail/utils/FieldOverrider');
var NodeVersion = require('../detail/utils/NodeVersion');

var bluebirdCompatibilityTestcase = function(
  configuration,
  expectedOutput,
  bluebird
) {
  return function() {
    var originalSetImmediate = global.setImmediate;
    var called = 0;

    return zurvan
      .interceptTimers(configuration)
      .then(function() {
        assert.notStrictEqual(originalSetImmediate, setImmediate);
        assert.strictEqual(originalSetImmediate.call, setImmediate.call);
        assert.strictEqual(originalSetImmediate.bind, setImmediate.bind);
        assert.strictEqual(originalSetImmediate.apply, setImmediate.apply);
      })
      .then(function() {
        new bluebird(function(resolve) {
          resolve();
        })
          .then(function() {
            return new bluebird(function(resolve) {
              process.nextTick(function() {
                resolve();
              });
            });
          })
          .then(function() {
            return new bluebird(function(resolve) {
              process.nextTick(function() {
                resolve();
              });
            }).then(function() {
              return bluebird.resolve();
            });
          })
          .then(function() {
            ++called;
          });
        return zurvan.waitForEmptyQueue();
      })
      .then(function() {
        assert.equal(called, expectedOutput);
        return zurvan.releaseTimers();
      })
      .then(function() {
        assert.strictEqual(originalSetImmediate, setImmediate);
      });
  };
};

describe('zurvan', function() {
  // bluebird uses a different scheduler for promises than node engine does - namely, setImmediate (macroqueue),
  // while V8 schedules promises on microqueue. Additionally, bluebird captures global.setImmediate in a local variable,
  // thus making it insufficient to change setTimeout itself. Luckily, it uses setImmediate.call (at least up to version 3.0)
  // so making setImmediate.call look like faked setImmediate does the trick. For version 3.0 and earlier
  describe('under special configuration (for compatibility with external libraries)', function() {
    it(
      'specially for bluebird changes its scheduler',
      bluebirdCompatibilityTestcase({ bluebird: bluebird }, 1, bluebird)
    );
    it('throws on wrong type of bluebird configuration parameter', function(done) {
      zurvan.interceptTimers({ bluebird: {} }).then(
        function() {
          done(new Error('Should not accept object as bluebird'));
        },
        function() {
          done();
        }
      );
    });
  });
});