Update Jenkinsfile

* This time, switch back to Python 2, use "pytest" to generate JUnit XML report that gets exposed through Jenkins, then archive the Linux executable.

jenkins/Jenkinsfile

@@ -4,32 +4,42 @@ pipeline {
         stage('Build') {
             agent {
                 docker {
-                    image 'python:3.4-slim'
+                    image 'python:2-alpine'
                 }
             }
             steps {
-                sh 'python -m py_compile sources/add2vals.py'
+                sh 'python -m py_compile sources/add2vals.py sources/calc.py'
             }
         }
         stage('Test') {
             agent {
                 docker {
-                    image 'python:3.4-slim'
+                    image 'qnib/pytest'
                 }
             }
             steps {
-                sh 'python sources/test_calc.py'
+                sh 'py.test --verbose --junit-xml test-reports/results.xml sources/test_calc.py'
+            }
+            post {
+                always {
+                    junit 'test-reports/results.xml'
+                }
             }
         }
         stage('Deliver') {
             agent {
                 docker {
-                    image 'cdrx/pyinstaller-linux'
+                    image 'cdrx/pyinstaller-linux:python2'
                 }
             }
             steps {
                 sh 'pyinstaller --onefile sources/add2vals.py'
             }
+            post {
+                success {
+                    archiveArtifacts 'dist/add2vals'
+                }
+            }
         }
     }
 }