Inconsistent test results between prb test and pub run test on Chrome

[cedx]

• Dart SDK Version: 2.0.0 (Fri Aug 3 10:53:23 2018 +0200) on "windows_x64"
• build_runner: 0.10.0, build_test: 0.10.3, build_web_compilers: 0.4.1, test: 1.3.0
• OS: Windows 10 (64-bit)
• Test browser: Chrome
• Any other packages or constraints: json_annotation: 1.0.0, json_serializable: 1.0.1.

I don't know if it's the right repo to post this issue, but it's when using build_test that the issue raises.
The problem appeared when testing the lcov package (version 4.3.0, see https://github.com/cedx/lcov.dart).

If I build the package manually using pub run build_runner build, and then launch the tests using pub run test, everything is OK:

$ pub run build_runner build # OK
$ pub run test --platform=vm # All tests passed!
$ pub run test --platform=chrome # All tests passed!

If I use pub run build_runner test for testing, the issue raises:

$ pub build_runner test -- --platform=vm # All tests passed!
$ pub build_runner test -- --platform=chrome # Error!!!

With the following error:

Running tests...

00:03 +8 -1: test\function_test.dart: FunctionCoverage .toString() should return a format like "FNF:<found>\n,FNH:<hit>" [E]
  Expected: 'FN:127,main\n'
              'FNDA:3,main\n'
              'FNF:3\n'
              'FNH:19'
    Actual: 'FNDA:3,main\n'
              'FNDA:3,main\n'
              'FNF:3\n'
              'FNH:19'
     Which: is different.
            Expected: FN:127,main\ ...
              Actual: FNDA:3,main\ ...
                        ^
             Differ at offset 2

  package:test             expect
  function_test.dart 53:9  test$.test.dart.fn

The FunctionCoverage#toString() method calls the FunctionData#toString({bool asDefinition = false}) method two times : the first time with asDefinition = true, the second time with asDefinition = false.
Cf. https://github.com/cedx/lcov.dart/blob/master/lib/src/function.dart#L36

It seems that when the project is compiled by build_test/build_web_comilers, the optional named parameter asDefinition is ignored.

[jakemac53]

One difference here is the dev compiler versus dart2js, can you try with

pub run build_runner test --release -- -p chrome

and see if that passes?

[cedx]

Well seen! Now, all tests are OK. Thanks @jakemac53.
I guess I should file an issue into the SDK repo...

[jakemac53]

Ya, I would file something on the sdk about the difference :)

[matanlurey]

I believe this is/was a bug in DDC's toString(): dart-lang/sdk#33876

It might not have made it into 2.0, but I imagine it will be in a subsequent release.