pkg/unittest: fixed asserts around currentTestCase

pkg/unittest: fixed asserts around currentTestCase

Fixed asserts originally in https://codereview.chromium.org/12328090/
removed by https://codereview.chromium.org/12330145/
Committed: https://code.google.com/p/dart/source/detail?r=19088

[kevmoo-old, 2013-02-26 19:17:32]

Re-ran tests in checked mode. Won't make that mistake again.

[Siggi Cherem (dart-lang), 2013-02-26 19:37:37]

No problem gram, I'll wait =)

I think the reason it failed in checked mode is simply that assertions are off
by default in production mode.

https://codereview.chromium.org/12340082/diff/1/pkg/unittest/lib/src/config.dart
File pkg/unittest/lib/src/config.dart (right):

https://codereview.chromium.org/12340082/diff/1/pkg/unittest/lib/src/config.d...
pkg/unittest/lib/src/config.dart:66: if(_currentTestCase != null) {
nit: since this is just for assertions and nothing else, we could do this inline
instead:
assert(_currentTestCase == null || _currentTestCase == testCase);

[kevmoo-old, 2013-02-26 19:39:51]

Context for the failure: 

It's possible for a test case to throw async errors after it's been marked
finished, in which case onTestResult is called a second time after the async
error is caught.

See test: 'late exception test'

Siggi: I'll take a look at the nit

[kevmoo-old, 2013-02-26 21:40:56]

nit fixed. If it LGTY, please commit.

[gram, 2013-02-26 21:42:12]

lgtm

https://codereview.chromium.org/12340082/diff/1002/pkg/unittest/lib/src/confi...
File pkg/unittest/lib/src/config.dart (right):

https://codereview.chromium.org/12340082/diff/1002/pkg/unittest/lib/src/confi...
pkg/unittest/lib/src/config.dart:66: assert(_currentTestCase == null ||
_currentTestCase == testCase);
This is just begging for an XOR logical operator, isn't it!

[gram, 2013-02-26 22:06:11]

Committed patchset #2 manually as r19088 (presubmit successful).