If I try to run the tests I'm getting:

    ### Running browser tests
    Traceback (most recent call last):
      File "test.py", line 954, in <module>
        main()
      File "test.py", line 941, in main
        browsers = setUp(options)
      File "test.py", line 609, in setUp
        assert not GIT_CLONE_CHECK or os.path.isfile('../src/pdf.js') and os.path.isdir('../.git')
    AssertionError
    sunbox:pdf_js (1) sunbox$ 

What are I'm doing wrong?