[bug#70570] [PATCH 2/2] guix: pyproject-build-system: Ignore unwanted pytest flags.

[Nicolas Graves]

* guix/build/pyproject-build-system.scm : Ignore unwanted pytest flags.

Change-Id: Ib9f1602e5af11227e5b7ce124f0f9be4fa2b78e4
---
 guix/build/pyproject-build-system.scm | 88 ++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/guix/build/pyproject-build-system.scm 
b/guix/build/pyproject-build-system.scm
index 947d240114..3ca3c76c1c 100644
--- a/guix/build/pyproject-build-system.scm
+++ b/guix/build/pyproject-build-system.scm
@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
 ;;; Copyright © 2022 Marius Bakke <marius@gnu.org>
+;;; Copyright © 2024 Nicolas Graves <ngraves@ngraves.fr>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -142,7 +143,86 @@ (define* (build #:key outputs build-backend backend-path 
configure-flags #:allow
      wheel-dir
      config-settings)))
 
-(define* (check #:key tests? test-backend test-flags #:allow-other-keys)
+;; Pytest plugin to filter out arguments to ignore.
+(define pytest-default-ignore-alist
+  '(("cov" . ("--cov" "--cov-reset" "--cov-report" "--cov-config"
+              "--no-cov-on-fail" "--no-cov" "--cov-fail-under"
+              "--cov-append" "--cov-branch" "--cov-context"))
+    ("mypy" . ("--mypy" "--mypy-config-file" "--mypy-ignore-missing-imports"))
+    ("isort" . ("--isort"))
+    ("flake8" . ("--flake8"))
+    ("black" . ("--black"))
+    ("flakes" . ("--flakes"))
+    ("pep8" . ("--pep8"))))
+
+;; Allow guix to ignore these options when underlying pytest package is not
+;; an input. These flags are not necessary to properly run tests.
+(define (pytest-ignore-options-plugin flags)
+  "This function converts an list of flags in a string that can
+  be instantiated as a python pytest plugin."
+  (format #f "\
+import pytest
+
+def pytest_addoption(parser):
+    group = parser.getgroup('guix','Guix ignored options')
+    options = [~{~s, ~}]
+    for option in options:
+        group.addoption(option, action='append', nargs='*')"
+          flags))
+
+(define (call-with-guix-pytest-plugin inputs thunk)
+  (let* ((former-path (getenv "PYTHONPATH"))
+         (input-names
+          (filter (match-lambda
+                    (((name . _) ...)
+                     (if (string-prefix? "python-pytest-" name)
+                         name
+                         #f))
+                    ( _ #f))
+                  inputs))
+         (filtered-flags
+          (filter identity
+                  (append-map
+                   (match-lambda
+                     ((group . flags)
+                      (if (member (string-append "python-pytest-" group)
+                                  input-names)
+                          (list #f)
+                          flags))
+                     (_ (list #f)))
+                   pytest-default-ignore-alist))))
+    (dynamic-wind
+      (lambda ()
+        (setenv "PYTHONPATH"
+                (string-append
+                 (if former-path
+                     (string-append former-path ":")
+                     "")
+                 ".guix-pytest"))
+        (setenv "PYTEST_PLUGINS"
+                (string-append
+                 (if (getenv "PYTEST_PLUGINS")
+                     (string-append former-path ",")
+                     "")
+                 "pytest_guix_plugin"))
+        (mkdir-p ".guix-pytest")
+        (with-output-to-file ".guix-pytest/__init__.py"
+          (lambda _ (display "")))
+        (with-output-to-file ".guix-pytest/pytest_guix_plugin.py"
+          (lambda _
+            (display (pytest-ignore-options-plugin filtered-flags)))))
+      thunk
+      (lambda ()
+        (setenv "PYTHONPATH" former-path)
+        (unsetenv "PYTEST_PLUGINS")
+        (when (file-exists? ".guix-pytest")
+          (delete-file-recursively ".guix-pytest"))))))
+
+(define-syntax-rule (with-guix-pytest-plugin inputs exp ...)
+  "Evaluate EXP in a context where the Guix pytest plugin is added."
+  (call-with-guix-pytest-plugin inputs (lambda () exp ...)))
+
+(define* (check #:key inputs tests? test-backend test-flags #:allow-other-keys)
   "Run the test suite of a given Python package."
   (if tests?
       ;; Unfortunately with PEP 517 there is no common method to specify test
@@ -165,7 +245,8 @@ (define* (check #:key tests? test-backend test-flags 
#:allow-other-keys)
         (format #t "Using ~a~%" use-test-backend)
         (match use-test-backend
           ('pytest
-           (apply invoke pytest "-vv" test-flags))
+           (with-guix-pytest-plugin inputs
+             (apply invoke pytest "-vv" test-flags)))
           ('nose
            (apply invoke nosetests "-v" test-flags))
           ('nose2
@@ -386,3 +467,6 @@ (define* (pyproject-build #:key inputs (phases 
%standard-phases)
   (apply python:python-build #:inputs inputs #:phases phases args))
 
 ;;; pyproject-build-system.scm ends here
+;;; Local Variables:
+;;; eval: (put 'with-guix-pytest-plugin 'scheme-indent-function 1)
+;;; End:
-- 
2.41.0