Support subsets of tests

[twilsonco]

I'd like to enable use of LocalCoverage.jl with subsets of tests by providing three optional arguments to generate_coverage() (and to any functions that call generate_coverage()):

1. test_args::String which is simply passed along to Pkg.test()
2. folder_list::Vector{String} a list of paths to directories for `process_folder(), and
3. file_list::Vector{String} a list of paths to files for process_file()

generate_coverage() would then be changed:

function generate_coverage(pkg = nothing; run_test = true, test_args = "", folder_list = ["src"], file_list = [])
    if run_test
        # passing `test_args` to `Pkg.test()`
        isnothing(pkg) ? Pkg.test(; coverage = true, test_args = test_args) : Pkg.test(pkg; coverage = true, test_args = test_args)
    end
    package_dir = pkgdir(pkg)
    cd(package_dir) do
        # initialize empty vector of coverage data
        coverage = Vector{CoverageTools.FileCoverage}()
        # process folders (same as default if `folder_list` isn't provided)
        for f in folder_list
            append!(coverage, process_folder(f))
        end
        # process individual files
        for f in file_list
            push!(coverage, process_file(f))
        end
        mkpath(COVDIR)
        tracefile = joinpath(COVDIR, LCOVINFO)
        CoverageTools.LCOV.writefile(tracefile, coverage)
        CoverageTools.clean_folder("./")
        eval_coverage_metrics(coverage, package_dir)
    end
end

Motivation

I have a project where testing is compartmentalized, using test_args, based on which files changed. Using Coverage.jl I can then use process_folder() and process_file() on the different directories/files that were included in the test so that coverage is accurate for the tests run.

Data loaders - 627/648 lines covered (96.76%)
Analysis routines - 86/93 lines covered (92.47%)

I'd like to be able to achieve the same effect with LocalCoverage.jl

I'm happy to PR this.

[tpapp]

Great idea, a PR would be welcome.

[twilsonco]

Awesome. I'll put one together!

[twilsonco]

@tpapp #46