mirror of
https://github.com/simplex-chat/haskell.nix.git
synced 2026-06-03 09:17:32 +00:00
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.
124 lines
3.6 KiB
Markdown
124 lines
3.6 KiB
Markdown
# Coverage
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haskell.nix can generate coverage information for your package or
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project using Cabal's inbuilt hpc support.
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## Prerequisites
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To get a sensible coverage report, you need to enable coverage on each
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of the packages of your project:
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```nix
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pkgs.haskell-nix.project {
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src = pkgs.haskell-nix.haskellLib.cleanGit {
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name = "haskell-nix-project";
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src = ./.;
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};
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compiler-nix-name = "ghc884";
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modules = [{
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packages.$pkg.components.library.doCoverage = true;
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}];
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}
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```
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If you would like to make coverage optional, add an argument to your nix expression:
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```nix
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{ withCoverage ? false }:
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pkgs.haskell-nix.project {
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src = pkgs.haskell-nix.haskellLib.cleanGit {
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name = "haskell-nix-project";
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src = ./.;
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};
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compiler-nix-name = "ghc884";
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modules = pkgs.lib.optional withCoverage [{
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packages.$pkg.components.library.doCoverage = true;
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}];
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}
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```
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## Per-package
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```bash
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nix-build default.nix -A "projectWithCoverage.$pkg.coverageReport"
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```
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This will generate a coverage report for the package you requested.
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All tests that are enabled (configured with `doCheck == true`) are
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included in the coverage report.
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See the [developer coverage docs](../dev/coverage.md#package-reports) for more information.
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## Project-wide
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```bash
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nix-build default.nix -A "projectWithCoverage.projectCoverageReport"
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```
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This will generate a coverage report for all the local packages in
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your project.
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See the [developer coverage docs](../dev/coverage.md#project-wide-reports) for more information.
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## Custom
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By default, the behaviour of the `coverageReport` attribute is to
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generate a coverage report that describes how that package affects the
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coverage of all local packages (including itself) in the project.
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The default behaviour of `projectCoverageReport` is to sum the
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default coverage reports (produced by the above process) of all local
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packages in the project.
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You can modify this behaviour by using the `coverageReport` and
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`projectCoverageReport` functions found in the haskell.nix library:
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```nix
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let
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inherit (pkgs.haskell-nix) haskellLib;
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project = haskellLib.project {
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src = pkgs.haskell-nix.haskellLib.cleanGit {
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name = "haskell-nix-project";
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src = ./.;
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};
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compiler-nix-name = "ghc884";
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modules = [{
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packages.$pkgA.components.library.doCoverage = true;
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packages.$pkgB.components.library.doCoverage = true;
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}];
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};
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# Generate a coverage report for $pkgA that only includes the
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# unit-test check and only shows coverage information for $pkgA, not
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# $pkgB.
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custom$pkgACoverageReport = haskellLib.coverageReport rec {
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name = "$pkgA-unit-tests-only"
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inherit (project.$pkgA.components) library;
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checks = [project.$pkgA.components.checks.unit-test];
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# Note that this is the default value of the "mixLibraries"
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# argument and so this line isn't really necessary.
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mixLibraries = [project.$pkgA.components.library];
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};
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custom$pkgBCoverageReport = haskellLib.coverageReport rec {
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name = "$pkgB-unit-tests-only"
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inherit (project.$pkgB.components) library;
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checks = [project.$pkgB.components.checks.unit-test];
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mixLibraries = [project.$pkgB.components.library];
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};
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# Generate a project coverage report that only includes the unit
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# tests of the project, and only shows how each unit test effects
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# the coverage of it's package, and not other packages in the
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# project.
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allUnitTestsProjectReport = haskellLib.projectCoverageReport [custom$pkgACoverageReport custom$pkgBCoverageReport];
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in {
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inherit project custom$pkgACoverageReport custom$pkgBCoverageReport allUnitTestsProjectCoverageReport;
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}
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```
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