Samuel Evans-Powell
48b8674f5f
- Added the ability to generate coverage reports for packages and projects. - Outputs mix and tix information, as well as a HTML report. - Added the "doCoverage" module option that allows users to choose packages to enable coverage for. - Added a "doCoverage" flag to the component builder that outputs HPC information when coverage is enabled. - Added the "overrideModules" library function to make it more ergonomic fo users to enable coverage on existing projects. - Modified the "check" builder to also output ".tix" files (if they exist). This information is required to generate the coverage report. - Added a test for coverage.
3.6 KiB
Coverage
haskell.nix can generate coverage information for your package or project using Cabal's inbuilt hpc support.
Prerequisites
To get a sensible coverage report, you need to enable coverage on each of the packages of your project:
pkgs.haskell-nix.project {
src = pkgs.haskell-nix.haskellLib.cleanGit {
name = "haskell-nix-project";
src = ./.;
};
compiler-nix-name = "ghc884";
modules = [{
packages.$pkg.components.library.doCoverage = true;
}];
}
If you would like to make coverage optional, add an argument to your nix expression:
{ withCoverage ? false }:
pkgs.haskell-nix.project {
src = pkgs.haskell-nix.haskellLib.cleanGit {
name = "haskell-nix-project";
src = ./.;
};
compiler-nix-name = "ghc884";
modules = pkgs.lib.optional withCoverage [{
packages.$pkg.components.library.doCoverage = true;
}];
}
Per-package
nix-build default.nix -A "projectWithCoverage.$pkg.coverageReport"
This will generate a coverage report for the package you requested.
All tests that are enabled (configured with doCheck == true) are
included in the coverage report.
See the developer coverage docs for more information.
Project-wide
nix-build default.nix -A "projectWithCoverage.projectCoverageReport"
This will generate a coverage report for all the local packages in your project.
See the developer coverage docs for more information.
Custom
By default, the behaviour of the coverageReport attribute is to
generate a coverage report that describes how that package affects the
coverage of all local packages (including itself) in the project.
The default behaviour of projectCoverageReport is to sum the
default coverage reports (produced by the above process) of all local
packages in the project.
You can modify this behaviour by using the coverageReport and
projectCoverageReport functions found in the haskell.nix library:
let
inherit (pkgs.haskell-nix) haskellLib;
project = haskellLib.project {
src = pkgs.haskell-nix.haskellLib.cleanGit {
name = "haskell-nix-project";
src = ./.;
};
compiler-nix-name = "ghc884";
modules = [{
packages.$pkgA.components.library.doCoverage = true;
packages.$pkgB.components.library.doCoverage = true;
}];
};
# Generate a coverage report for $pkgA that only includes the
# unit-test check and only shows coverage information for $pkgA, not
# $pkgB.
custom$pkgACoverageReport = haskellLib.coverageReport rec {
name = "$pkgA-unit-tests-only"
inherit (project.$pkgA.components) library;
checks = [project.$pkgA.components.checks.unit-test];
# Note that this is the default value of the "mixLibraries"
# argument and so this line isn't really necessary.
mixLibraries = [project.$pkgA.components.library];
};
custom$pkgBCoverageReport = haskellLib.coverageReport rec {
name = "$pkgB-unit-tests-only"
inherit (project.$pkgB.components) library;
checks = [project.$pkgB.components.checks.unit-test];
mixLibraries = [project.$pkgB.components.library];
};
# Generate a project coverage report that only includes the unit
# tests of the project, and only shows how each unit test effects
# the coverage of it's package, and not other packages in the
# project.
allUnitTestsProjectReport = haskellLib.projectCoverageReport [custom$pkgACoverageReport custom$pkgBCoverageReport];
in {
inherit project custom$pkgACoverageReport custom$pkgBCoverageReport allUnitTestsProjectCoverageReport;
}