pre-commit: enable tests

used arch and openSUSE packages for reference

pkgs/tools/misc/pre-commit/default.nix

@@ -1,4 +1,13 @@
-{ lib, python3Packages }:
+{ lib
+, python3Packages
+, fetchFromGitHub
+  # tests
+, cargo
+, dotnet-sdk
+, git
+, go
+, nodejs
+}:
 
 with python3Packages;
 buildPythonPackage rec {
@@ -8,10 +17,11 @@ buildPythonPackage rec {
 
   disabled = pythonOlder "3.6";
 
-  src = fetchPypi {
-    inherit version;
-    pname = "pre_commit";
-    sha256 = "sha256-XURe4fqHONUGiBxdhPg8Yrtb5rKDjjIgdDNkfo5evhA=";
+  src = fetchFromGitHub {
+    owner = "pre-commit";
+    repo = "pre-commit";
+    rev = "v${version}";
+    sha256 = "sha256-d/ukUTjNgpqr6IeDJHDaOXQm0EdsX+vq0sVX7HG3gSE=";
   };
 
   patches = [
@@ -32,18 +42,103 @@ buildPythonPackage rec {
     importlib-resources
   ];
 
-  # slow and impure
-  doCheck = false;
+  checkInputs = [
+    cargo
+    dotnet-sdk
+    git
+    go
+    nodejs
+    pytest-env
+    pytest-xdist
+    pytestCheckHook
+    re-assert
+  ];
 
-  preFixup = ''
-    substituteInPlace $out/${python.sitePackages}/pre_commit/resources/hook-tmpl \
+  doCheck = true;
+
+  postPatch = ''
+    substituteInPlace pre_commit/resources/hook-tmpl \
       --subst-var-by pre-commit $out
-    substituteInPlace $out/${python.sitePackages}/pre_commit/languages/python.py \
+    substituteInPlace pre_commit/languages/python.py \
       --subst-var-by virtualenv ${virtualenv}
-    substituteInPlace $out/${python.sitePackages}/pre_commit/languages/node.py \
+    substituteInPlace pre_commit/languages/node.py \
       --subst-var-by nodeenv ${nodeenv}
+
+    patchShebangs pre_commit/resources/hook-tmpl
   '';
 
+  pytestFlagsArray = [
+    "--numprocesses $NIX_BUILD_CORES"
+    "--forked"
+  ];
+
+  preCheck = ''
+    export GIT_AUTHOR_NAME=test GIT_COMMITTER_NAME=test \
+           GIT_AUTHOR_EMAIL=test@example.com GIT_COMMITTER_EMAIL=test@example.com \
+           VIRTUALENV_NO_DOWNLOAD=1 PRE_COMMIT_NO_CONCURRENCY=1 LANG=en_US.UTF-8
+
+    git init -b master
+
+    export HOME=$(mktemp -d)
+
+    python -m venv --system-site-packages venv
+    source "$PWD/venv/bin/activate"
+    #$out/bin/pre-commit install
+    python setup.py develop
+  '';
+
+  postCheck = ''
+    deactivate
+  '';
+
+  disabledTests = [
+    # ERROR: The install method you used for conda--probably either `pip install conda`
+    # or `easy_install conda`--is not compatible with using conda as an application.
+    "test_conda_"
+    "test_local_conda_"
+
+    # /build/pytest-of-nixbld/pytest-0/test_install_ruby_with_version0/rbenv-2.7.2/libexec/rbenv-init:
+    # /usr/bin/env: bad interpreter: No such file or directory
+    "ruby"
+
+    # network
+    "test_additional_dependencies_roll_forward"
+    "test_additional_golang_dependencies_installed"
+    "test_additional_node_dependencies_installed"
+    "test_additional_rust_cli_dependencies_installed"
+    "test_additional_rust_lib_dependencies_installed"
+    "test_dart_hook"
+    "test_dotnet_hook"
+    "test_golang_hook"
+    "test_golang_hook_still_works_when_gobin_is_set"
+    "test_installs_without_links_outside_env"
+    "test_local_dart_additional_dependencies"
+    "test_local_golang_additional_dependencies"
+    "test_local_lua_additional_dependencies"
+    "test_local_perl_additional_dependencies"
+    "test_local_rust_additional_dependencies"
+    "test_lua_hook"
+    "test_perl_hook"
+    "test_r_hook"
+    "test_r_inline_hook"
+    "test_r_local_with_additional_dependencies_hook"
+    "test_r_with_additional_dependencies_hook"
+    "test_run_a_node_hook_default_version"
+    "test_run_versioned_node_hook"
+
+    # python2, no explanation needed
+    "python2"
+    "test_switch_language_versions_doesnt_clobber"
+
+    # docker
+    "test_run_a_docker_hook"
+
+    # i don't know why these fail
+    "test_install_existing_hooks_no_overwrite"
+    "test_installed_from_venv"
+    "test_uninstall_restores_legacy_hooks"
+  ];
+
   pythonImportsCheck = [
     "pre_commit"
   ];