ci: speed up CI using multiple processes with pytest (#67083)

Jenkinsfile

@@ -8,7 +8,7 @@ pipeline {
     stages {
         stage('Unit Tests') {
             steps {
-                sh 'tox -rv'
+                sh 'NUMPROCESSES=6 tox -rv '
             }
             post {
                 always {

tox.ini

@@ -19,6 +19,7 @@ commands =
 [testenv]
 usedevelop = true
 setenv =
+	NUMPROCESSES={env:NUMPROCESSES:1}
 	DJANGO_SETTINGS_MODULE=bijoe.settings
 	BIJOE_SETTINGS_FILE=tests/settings.py
 	SETUPTOOLS_USE_DISTUTILS=stdlib
@@ -30,6 +31,7 @@ deps =
 	pytest-cov
 	pytest-django
 	pytest-freezegun
+	pytest-xdist
 	WebTest
 	django-webtest<1.9.3
 	mock
@@ -41,7 +43,7 @@ deps =
 	dj22: djangorestframework>=3.7
 	dj22: https://git.entrouvert.org/hobo.git/snapshot/hobo-main.tar.gz
 commands =
-        py3-dj22: py.test {posargs: --junitxml=test_{envname}_results.xml --cov-report xml --cov-report html --cov=bijoe tests/}
+        py3-dj22: py.test {posargs: --numprocesses {env:NUMPROCESSES:1} --junitxml=test_{envname}_results.xml --cov-report xml --cov-report html --cov=bijoe tests/}
 
 [pytest]
 filterwarnings =