Jenkinsfile: use virtualenv and pg_virtualenv

Jenkinsfile

@@ -2,10 +2,18 @@
 
 pipeline {
     agent any
+    options { disableConcurrentBuilds() }
+    environment {
+        TMPDIR = "/tmp/$BUILD_TAG"
+    }
     stages {
         stage('Unit Tests') {
             steps {
-                sh 'tox -rv'
+                sh "mkdir ${env.TMPDIR}"
+                sh """
+virtualenv -p python3 ${env.TMPDIR}/venv/
+${env.TMPDIR}/venv/bin/pip install tox
+PGPORT=`python -c 'import struct; import socket; s=socket.socket(); s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, struct.pack("ii", 1, 0)); s.bind(("", 0)); print(s.getsockname()[1]); s.close()'` pg_virtualenv -o fsync=off ${env.TMPDIR}/venv/bin/tox -r"""
             }
             post {
                 always {
@@ -15,7 +23,7 @@ pipeline {
                         utils.publish_coverage_native('index.html')
                         utils.publish_pylint('pylint.out')
                     }
-                    junit '*_results.xml'
+                    mergeJunitResults()
                 }
             }
         }
@@ -37,6 +45,7 @@ pipeline {
             }
         }
         success {
+            sh "rm -rf ${env.TMPDIR}"
             cleanWs()
         }
     }