Compilation through Ruby Compass broken

[Snugug]

As of Compass 1.0.0.alpha.16, the following code (which previously worked) throws errors. I have tested with .16 and .17, but not yet with Master (will post a follow-up comment with Master)

The Rakefile used to run these tests can be found in Singularity's Tests. Currently at .13 through Bundler, updating to .16 or greater will cause the error.

Reduced offending Ruby code (full code)

Compass.compiler.sass_files.each do |sass_file|
  test_file_pwd = Compass.compiler.corresponding_css_file(sass_file)
  Compass.compiler.compile sass_file, test_file_pwd
end

Stack trace:

TypeError: no implicit conversion of nil into String
    /usr/local/gems/compass-1.0.0.alpha.17/lib/compass/compiler.rb:181:in `exist?'
    /usr/local/gems/compass-1.0.0.alpha.17/lib/compass/compiler.rb:181:in `compile'
    .unit_tests.rb:34:in `block (2 levels) in <class:TestCompassOutput>'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1301:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit/testcase.rb:17:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:919:in `block in _run_suite'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:912:in `map'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:912:in `_run_suite'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:657:in `block in _run_suites'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:655:in `each'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:655:in `_run_suites'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:867:in `_run_anything'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1060:in `run_tests'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1047:in `block in _run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1046:in `each'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1046:in `_run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/minitest/unit.rb:1035:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:21:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:774:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:366:in `block (2 levels) in autorun'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:27:in `run_once'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/test/unit.rb:365:in `block in autorun'

[JohnAlbin]

It looks like @chriseppstein fixed this in 2df1df7 :-)

It is a post-1.0.0-alpha.17 commit. I haven't tested the fix in master, but I did see the bug in the 1.0.0.alpha.17.