unittest.dart does not compare lists correctly

[DartBot]

This issue was originally filed by reng...@gmail.com

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What steps will reproduce the problem?

  #import('/Applications/Dart/dart-sdk/lib/unittest/unittest.dart');

  void main() {
    test('compare empty list', () {
      expect([]).equals([]);
    });
    test('compare one element list', () {
      expect([1]).equals([1]);
    });
    test('compare longer list', () {
      expect([1, 2, 3]).equals([1, 2, 3]);
    });
  }

What is the expected output?

  3 PASSED, 0 FAILED, 0 ERRORS

What do you see instead?

  FAIL: compare empty list
    Expect.equals(expected: <[]>, actual: <[]>) fails.
     0. Function: 'Expect._fail@127eafe4' url: 'bootstrap' line:563 col:66
     1. Function: 'Expect.equals' url: 'bootstrap' line:518 col:173
     2. Function: 'Expectation.equals' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/expectation.dart' line:27 col:20
     3. Function: '::function' url: 'file:///Users/renggli/dart/TestTester/TestTester.dart' line:5 col:22
     4. Function: '::function' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:521 col:20
     5. Function: '::guardAsync' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:485 col:19
  
  FAIL: compare one element list
    Expect.equals(expected: <[1]>, actual: <[1]>) fails.
     0. Function: 'Expect._fail@127eafe4' url: 'bootstrap' line:563 col:66
     1. Function: 'Expect.equals' url: 'bootstrap' line:518 col:173
     2. Function: 'Expectation.equals' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/expectation.dart' line:27 col:20
     3. Function: '::function' url: 'file:///Users/renggli/dart/TestTester/TestTester.dart' line:8 col:23
     4. Function: '::function' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:521 col:20
     5. Function: '::guardAsync' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:485 col:19
  
  FAIL: compare longer list
    Expect.equals(expected: <[1, 2, 3]>, actual: <[1, 2, 3]>) fails.
     0. Function: 'Expect._fail@127eafe4' url: 'bootstrap' line:563 col:66
     1. Function: 'Expect.equals' url: 'bootstrap' line:518 col:173
     2. Function: 'Expectation.equals' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/expectation.dart' line:27 col:20
     3. Function: '::function' url: 'file:///Users/renggli/dart/TestTester/TestTester.dart' line:11 col:29
     4. Function: '::function' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:521 col:20
     5. Function: '::guardAsync' url: 'file:///Applications/Dart/dart-sdk/lib/unittest/unittest.dart' line:485 col:19

  0 PASSED, 3 FAILED, 0 ERRORS

What version of the product are you using? On what operating system?

  Dart SDK version 7904

Please provide any additional information below.

The problem can be fixed by adding the following snippet to Expectation.equals():

    } else if (_value is List && expected is List) {
      Expect.listEquals(expected, _value);

[kasperl]

Added Area-UnitTest, Triaged labels.

[DartBot]

This comment was originally written by reng...@gmail.com

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Similarly

   expect([[]]).equals([[]]);

and

   expect([{}]).equals([{}]);

are failing. In the context of tests I would expect that the same comparator also goes into nested literals.

[DartBot]

This comment was originally written by reng...@gmail.com

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I think this issue can be closed. The reported problem is no longer an issue with the new matchers:

    expect([[]], recursivelyMatches([[]]));

    expect([{}], recursivelyMatches([{}]));

[gramster]

Agree with previous comment, and note that the next SDK push will remove recursivelyMatches; you can just use equals:

  void main() {
    test('compare empty list', () {
      expect([], equals([]));
    });
    test('compare one element list', () {
      expect([1], equals([1]));
    });
    test('compare longer list', () {
      expect([1, 2, 3], equals([1, 2, 3]));
    });
  }

[gramster]

That said, perhaps someone should take a look at the original issue; that version of Expect is still used for core language tests.

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Removed Area-UnitTest label.
Added Area-Library label.

[gramster]

Added Fixed label.