How to get code coverage for @traitfn-wrapped functions?

[sbromberger]

I'm using @traitfn like this:

"""docstring"""
foo(x...) = error("Not implemented")            #1
@traitfn foo{X<:XType; IsMyTrait{X}}(x::X) = ...      #2
@traitfn foo{X<:XType; !IsMyTrait{X}}(x::X) = ...     #3

I can get code coverage for #1, but even when I do real tests on foo (#2 and #3), codecov complains that the method isn't tested.

Is there a recommended way to do this? (Also: is there a better way to associate a docstring other than creating a dummy non-traited function?)

[mauro3]

This would need something like https://github.com/bramtayl/NumberedLines.jl. I hope to do this at some point but it's not high on my priority list.

However, @bramtayl seems keen to see his package used: https://github.com/bramtayl/NumberedLines.jl/issues/1 . So maybe he'd work with you on a PR...

[bramtayl]

Hmm. I'm not sure I'm seeing what the issue is? It looks to me like the line number info is in the function body (fbody), which gets passed through untouched?

[mauro3]

Sorry, I got confused with my packages: this package has line number information (thanks to @timholy, see here) but Parameters.jl is lacking it. So, I'm not sure why coverage is not reported correctly but it seems a Julia-0.5 issue, as below tests show. @sbromberger can you check whether it works on 0.6?

Running:

# julia --code-coverage coverage-test.jl
using SimpleTraits, Base.Test
@traitdef Tr{X}
@traitimpl Tr{Int}

foo() = 1
@traitfn foo(x::::Tr) = 2
@traitfn foo(x::::(!Tr)) = 3

@test foo()==1
@test foo(1)==2
@test foo(1.0)==3

Julia 0.5 produces no .cov file at all. Conversely, running with 0.6 a .cov file is produced:

        - # julia --code-coverage coverage-test.jl
        - using SimpleTraits, Base.Test
        - @traitdef Tr{X}
        - @traitimpl Tr{Int}
        -
        1 foo() = 1
        2 @traitfn foo(x::::Tr) = 2
        2 @traitfn foo(x::::(!Tr)) = 3
        -
        - @test foo()==1
        - @test foo(1)==2
        - @test foo(1.0)==3

Not 100% right as it over-reports at least the second line. In fact, running a slightly different script shows the problem a bit better:

        - # julia --code-coverage coverage-test.jl
        - using SimpleTraits, Base.Test
        - @traitdef Tr{X}
        - @traitimpl Tr{Int}
        -
        1 foo() = 1
        2 @traitfn foo(x::::Tr) = 2
        - @traitfn function foo(x::::(!Tr))
        4     println("here") # over-reporting
        2     println("here") # over-reporting
        2     println("here") # correct
        2     if x>0
        1         return 3
        -     else
        1         return -3
        -     end
        - end
        -
        -
        - @test foo()==1
        - @test foo(1)==2
        - @test foo(1.0)==3
        - @test foo(-1.0)==-3

[mauro3]

@sbromberger did you check whether Julia-0.6 gives better coverage results?

[sbromberger]

@mauro3 I won't be able to do that for a while since we haven't migrated this branch to have compatibility with 0.6.

[mauro3]

Ok. I don't think there is anything for me to do here (and I certainly wouldn't know what). So, I'll close this. But if you figure something out, a PR is welcome.