Failing tests hidden by --probe-todo

[xzyfer]

A recent commit to LibSass has caused a spec to begin failing. The spec did not fail in CI. After some digging the issue appears to be related to the --probe-todo flag.

To reproduce compile sass/libsass@03c9fd1 and run

$ ruby sass-spec.rb -c `(echo $SASS_SASSC_PATH)`/bin/sassc --impl libsass spec/scss/interpolation-operators-precedence/ --version 3.4 --probe-todo

Recursively searching under /Users/xzyfer/Projects/Sass/sass-spec/spec/scss/interpolation-operators-precedence for test files to test 'libsass' against language version 3.4.
sassc: 3.3.3-3-ge054-dirty
libsass: 3.3.6-139-g2fcd
sass2scss: 1.1.0
Run options: --seed 53539

# Running:

-

Finished in 0.016065s, 62.2471 runs/s, 124.4942 assertions/s.

1 runs, 2 assertions, 0 failures, 0 errors, 1 skips

You have skipped tests. Run with --verbose for details.
Note: All tests marked as TODO for libsass are still failing.

With --probe-todo flag this spec is skipped. Without it the spec correctly fails.

$ruby sass-spec.rb -c `(echo $SASS_SASSC_PATH)`/bin/sassc --impl libsass spec/scss/interpolation-operators-precedence/ --version 3.4
Recursively searching under /Users/xzyfer/Projects/Sass/sass-spec/spec/scss/interpolation-operators-precedence for test files to test 'libsass' against language version 3.4.
sassc: 3.3.3-3-ge054-dirty
libsass: 3.3.6-139-g2fcd
sass2scss: 1.1.0
Run options: --seed 22851

# Running:

F

Finished in 0.034134s, 29.2963 runs/s, 87.8889 assertions/s.

  1) Failure:
SassSpec::Test#test__spec/scss/interpolation-operators-precedence [/Users/xzyfer/Projects/Sass/sass-spec/lib/sass_spec/test.rb:237]:
expected did not match output.
--- expected
+++ actual
@@ -17,7 +17,7 @@
   c07: a /5%-2;
   c08: a *5%-2;
   c09: a +2.5%;
-  c10: a -2.5%;
+  c10: a -5%/2;
   c11: a /2.5%;
   c12: a *2.5%;
   c13: a +10%;


1 runs, 3 assertions, 1 failures, 0 errors, 0 skips

[mgreter]

This should be resolved by now. Thanks @nex3!