chai/test/globalErr.js

describe('globalErr', function () {
  var noop = function () {}
    , Err = chai.AssertionError
    , expect = chai.expect;

  it('should pass if string val equals error message', function () {
    err(function () {
      expect('cat').to.equal('dog')
    }, 'expected \'cat\' to equal \'dog\'');
  });

  it('should pass if regex val matches error message', function () {
    err(function () {
      expect('cat').to.equal('dog')
    }, /expected 'cat' to equal 'dog'/);
  });

  it('should pass if object val\'s props are included in error object', function () {
    err(function () {
      expect('cat').to.equal('dog');
    }, {
        message: 'expected \'cat\' to equal \'dog\''
      , expected: 'dog'
      , actual: 'cat'
    });

    err(function () {
      expect({cat: 'meow'}).to.equal({dog: 'woof'});
    }, {
        message: 'expected { cat: \'meow\' } to equal { dog: \'woof\' }'
      , expected: {dog: 'woof'}
      , actual: {cat: 'meow'}
    });
  });

  it('should throw if string val does not equal error message', function () {
    err(function () {
      err(function () { throw new Err('cat') }, 'dog');
    }, {
        message: 'expected \'cat\' to equal \'dog\''
      , expected: 'dog'
      , actual: 'cat'
    });
  });

  it('should pass operator if possible during none object comparison', function () {
    err(function () {
      expect('cat').to.equal('dog');
    }, {
        message: 'expected \'cat\' to equal \'dog\''
      , expected: 'dog'
      , actual: 'cat'
      , operator: 'strictEqual'
    });

    err(function () {
      expect('cat').to.not.equal('cat');
    }, {
      message: 'expected \'cat\' to not equal \'cat\''
      , expected: 'cat'
      , actual: 'cat'
      , operator: 'notStrictEqual'
    });
  });

  it('should pass operator if possible during plain object comparison', function () {
    var val1 = {
      propVal1: 'val1'
    };

    var val2 = {
      propVal2: 'val2'
    };

    err(function () {
      expect(val1).to.equal(val2);
    }, {
        message: "expected { propVal1: 'val1' } to equal { propVal2: 'val2' }"
      , expected: val2
      , actual: val1
      , operator: 'deepStrictEqual'
    });

    err(function () {
      expect(val1).to.not.equal(val1);
    }, {
      message: "expected { propVal1: 'val1' } to not equal { propVal1: 'val1' }"
      , expected: val1
      , actual: val1
      , operator: 'notDeepStrictEqual'
    });
  });

  it('should pass operator if possible during function comparison', function () {
    function f1 () {
      this.propF1 = 'propF1';
    }

    function f2 () {
      this.propF2 = 'propF2';
    }

    err(function () {
      expect(f1).to.equal(f2);
    }, {
        message: "expected [Function f1] to equal [Function f2]"
      , expected: f2
      , actual: f1
      , operator: 'deepStrictEqual'
    });

    err(function () {
      expect(f1).to.not.equal(f1);
    }, {
      message: "expected [Function f1] to not equal [Function f1]"
      , expected: f1
      , actual: f1
      , operator: 'notDeepStrictEqual'
    });
  });

  it('should pass operator if possible during object comparison', function () {
    var val1 = [
        'string1'
      , 'string2'
      , 'string3'
      , 'string4'
    ];

    var val2 = [
      'string5'
    , 'string6'
    , 'string7'
    , 'string8'
    ];
    err(function () {
      expect(val1).to.equal(val2);
    }, {
        message: "expected [ 'string1', 'string2', …(2) ] to equal [ 'string5', 'string6', …(2) ]"
      , expected: val2
      , actual: val1
      , operator: 'deepStrictEqual'
    });

    err(function () {
      expect(val1).to.not.equal(val1);
    }, {
      message: "expected [ 'string1', 'string2', …(2) ] to not equal [ 'string1', 'string2', …(2) ]"
      , expected: val1
      , actual: val1
      , operator: 'notDeepStrictEqual'
    });
  });

  it('should throw if regex val does not match error message', function () {
    err(function () {
      err(function () { throw new Err('cat') }, /dog/);
    }, 'expected \'cat\' to match /dog/');
  });

  it('should throw if object val\'s props are not included in error object', function () {
    err(function () {
      err(function () { throw new Err('cat') }, {text: 'cat'});
    }, /expected AssertionError{ message: 'cat', …\(2\) } to have property \'text\'/);

    err(function () {
      err(function () { throw new Err('cat') }, {message: 'dog'});
    }, 'expected \'cat\' to deeply equal \'dog\'', true);
  });

  it('should throw if fn does not throw', function () {
    err(function () { err(noop) }, 'Expected an error');
  });

  it('should throw if fn is invalid', function () {
    var vals = [
        'cat'
      , 42
      , []
      , new RegExp()
      , new Date()
      , null
      , undefined
    ];

    if (typeof Symbol === 'function') vals.push(Symbol());
    if (typeof Map === 'function') vals.push(new Map());
    if (typeof WeakMap === 'function') vals.push(new WeakMap());
    if (typeof Set === 'function') vals.push(new Set());
    if (typeof WeakSet === 'function') vals.push(new WeakSet());
    if (typeof Promise === 'function') vals.push(new Promise(noop));

    vals.forEach(function (val) {
      err(function () { err(val) }, 'Invalid fn')
    });
  });

  it('should throw if val is invalid', function () {
    var vals = [
        42
      , []
      , new Date()
      , noop
      , null
    ];

    if (typeof Symbol === 'function') vals.push(Symbol());
    if (typeof Map === 'function') vals.push(new Map());
    if (typeof WeakMap === 'function') vals.push(new WeakMap());
    if (typeof Set === 'function') vals.push(new Set());
    if (typeof WeakSet === 'function') vals.push(new WeakSet());
    if (typeof Promise === 'function') vals.push(new Promise(noop));

    vals.forEach(function (val) {
      err(function () {
        err(function () { throw new Err('Test error') }, val)
      }, 'Invalid val')
    });
  });

  describe('skipStackTest', function () {
    // Skip tests if `Error.captureStackTrace` is unsupported
    if (typeof Error.captureStackTrace === 'undefined') return;

    try {
      throw Error();
    } catch (err) {
      // Skip tests if `err.stack` is unsupported
      if (typeof err.stack === 'undefined') return;
    }

    // Note: `.to.not.throw` isn't used for the assertions that aren't expected
    // to throw an error because it'll pollute the very same stack trace which
    // is being asserted on. Instead, if `err` throws an error, then Mocha will
    // use that error as the reason the test failed.
    describe('falsey', function () {
      it('should throw if "Getter" is in the stack trace', function () {
        err(function () {
          err(function fakeGetter () {
            throw Error('my stack trace contains a fake implementation frame');
          });
        }, /implementation frames not properly filtered from stack trace/, true);
      });

      it('should throw if "Wrapper" is in the stack trace', function () {
        err(function () {
          err(function fakeWrapper () {
            throw Error('my stack trace contains a fake implementation frame');
          });
        }, /implementation frames not properly filtered from stack trace/, true);
      });

      it('should throw if "assert" is in the stack trace', function () {
        err(function () {
          err(function assertFake () {
            throw Error('my stack trace contains a fake implementation frame');
          });
        }, /implementation frames not properly filtered from stack trace/, true);
      });

      it('shouldn\'t throw if "Getter", "Wrapper", "assert" aren\'t in the stack trace', function () {
        err(function safeFnName () {
          throw Error('my stack trace doesn\'t contain implementation frames');
        });
      });
    });

    describe('truthy', function () {
      it('shouldn\'t throw if "Getter" is in the stack trace', function () {
        err(function fakeGetter () {
          throw Error('my stack trace contains a fake implementation frame');
        }, undefined, true);
      });

      it('shouldn\'t throw if "Wrapper" is in the stack trace', function () {
        err(function fakeWrapper () {
          throw Error('my stack trace contains a fake implementation frame');
        }, undefined, true);
      });

      it('shouldn\'t throw if "assert" is in the stack trace', function () {
        err(function assertFake () {
          throw Error('my stack trace contains a fake implementation frame');
        }, undefined, true);
      });

      it('shouldn\'t throw if "Getter", "Wrapper", "assert" aren\'t in the stack trace', function () {
        err(function safeFnName () {
          throw Error('my stack trace doesn\'t contain implementation frames');
        }, undefined, true);
      });
    });
  });
});