See https://github.com/JuliaLang/julia/issues/11885 and https://github.com/JuliaLang/julia/issues/9493 for more details and discussion!
This would make a whole bunch of good "first contribution" projects, and does not require deep insider knowledge of the language.
The basic idea is to expand the test suite to make sure that
julia's base code works as promised. Here is one recommended way to contribute toward this goal:
Go visit https://coveralls.io/r/JuliaLang/julia or http://codecov.io/gh/JuliaLang/julia. (At the time of this writing, coverage numbers are in the 80s%. If you see numbers that are much lower than this, don't trust the reports; there is likely a problem in measuring coverage.)
Browse through the source files and find some untested functionality (highlighted in red) that you think you might be able to write a test for.
Write a test that exercises this functionality---you can add your test to one of the existing files, or start a new one, whichever seems most appropriate to you. If you're adding a new test file, make sure you include it in the list of tests in
test/choosetests.jl. http://julia.readthedocs.org/en/latest/stdlib/test/ may be helpful in explaining how the testing infrastructure works. Submit the test as a pull request (see