[bug#52078] [PATCH v2 3/3] build: julia-build-system: Allow parallel tests for package.

[zimoun <zimon.toutoune@gmail.com>]

The tests are defined by the script 'test/runtests.jl' from packages and the
parallelism depends on the implementation of this script.  Therefore, 'julia'
is launched using local worker processes accordingly with 'parallel?'.

* guix/build/julia-build-system.scm (check): Set JULIA_CPU_THREADS, add
options '--procs'.
* guix/build-system/julia.scm (julia-build): Add 'parallel-tests?'.
---
 guix/build-system/julia.scm       | 3 +++
 guix/build/julia-build-system.scm | 9 ++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/guix/build-system/julia.scm b/guix/build-system/julia.scm
index 2998663df1..6261f8a55a 100644
--- a/guix/build-system/julia.scm
+++ b/guix/build-system/julia.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2019 Nicolò Balzarotti <nicolo@nixo.xyz>
 ;;; Copyright © 2021 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2021 Jean-Baptiste Volatier <jbv@pm.me>
+;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -79,6 +80,7 @@ (define private-keywords
 (define* (julia-build name inputs
                       #:key source
                       (tests? #t)
+                      (parallel-tests? #t)
                       (phases '%standard-phases)
                       (outputs '("out"))
                       (search-paths '())
@@ -98,6 +100,7 @@ (define builder
                        #:source #+source
                        #:system #$system
                        #:tests? #$tests?
+                       #:parallel-tests? #$parallel-tests?
                        #:phases #$phases
                        #:outputs #$(outputs->gexp outputs)
                        #:search-paths '#$(sexp->gexp
diff --git a/guix/build/julia-build-system.scm b/guix/build/julia-build-system.scm
index 41c69665c6..f0dc419c17 100644
--- a/guix/build/julia-build-system.scm
+++ b/guix/build/julia-build-system.scm
@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2019, 2020 Nicolò Balzarotti <nicolo@nixo.xyz>
 ;;; Copyright © 2021 Jean-Baptiste Volatier <jbv@pm.me>
+;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -103,11 +104,15 @@ (define* (precompile #:key source inputs outputs julia-package-name
   #t)
 
 (define* (check #:key tests? source inputs outputs julia-package-name
+                parallel-tests?
                 #:allow-other-keys)
   (when tests?
     (let* ((out (assoc-ref outputs "out"))
            (package (or julia-package-name (project.toml->name "Project.toml")))
-           (builddir (string-append out "/share/julia/")))
+           (builddir (string-append out "/share/julia/"))
+           (jobs (if parallel-tests?
+                     (number->string (parallel-job-count))
+                     "1")))
       ;; With a patch, SOURCE_DATE_EPOCH is honored
       (setenv "SOURCE_DATE_EPOCH" "1")
       (setenv "JULIA_DEPOT_PATH" builddir)
@@ -115,8 +120,10 @@ (define* (check #:key tests? source inputs outputs julia-package-name
               (string-append builddir "loadpath/" ":"
                              (or (getenv "JULIA_LOAD_PATH")
                                  "")))
+      (setenv "JULIA_CPU_THREADS" jobs)
       (setenv "HOME" "/tmp")
       (invoke "julia" "--depwarn=yes"
+              (string-append "--procs=" jobs)
               (string-append builddir "loadpath/"
                              package "/test/runtests.jl"))))
   #t)
-- 
2.32.0