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Jenkins Part 4.2: Code Quality Tests via Checkstyle


2017-01-19-23_30_11

Today, we will show how to use Checkstyle for improving the style of Java code. First, we will add Checkstyle to Gradle in order to create XML reports for a single build. Jenkins allows us to visualize the results of more than one test/build run into historic reports. After that, we will show, how a developer can use the Eclipse Checkstyle plugin in order to create better code:

2017-02-01-04_43_16-github-triggered-build-jenkins

This blog post series is divided into following parts:

    • Part 1: Installation and Configuration of Jenkins, loading Plugins
    • Part 2: Creating our first Jenkins job: GitHub download and Software build
    • Part 3: Periodic and automatically triggered Builds
    • Part 4.1: running automated tests: Functional Tests via Java JUnit
    • Part 4.2: running automated tests: Code Quality Test via Checkstyle (this post)
    • Part 4.3: running automated tests: Performance Tests with JMeter (work in progress)

What is Jenkins?

Jenkins is the leading open source automation server mostly used in continuous integration and continuous deployment pipelines. Jenkins provides hundreds of plugins to support building, deploying and automating any project.

 

Jenkins build, test and deployment pipeline
Jenkins build, test and deployment pipeline

A typical workflow is visualized above: a developer checks in the code changes into the repository. Jenkins will detect the change, build (compile) the software, test it and prepare to deploy it on a system. Depending on the configuration, the deployment is triggered by a human person, or automatically performed by Jenkins.

For more information, see the introduction found in part 1 of this blog series.

Checking Code with Checkstyle

In this post, we will show how to configure Jenkins for automated code checking as part of the Post-Build Tests:

2017-01-19-04_15_46

After this tutorial has been followed, we will have learned how to apply standard or custom checks on the code quality using Checkstyle in Eclipse and Jenkins.

Tools & Versions used

      • Vagrant 1.8.6
      • Virtualbox 5.0.20
      • Docker 1.12.1
      • Jenkins 2.32.1
        • Checkstyle Plug-in 3.47
      • Eclipse Kepler Service Release 2 (Build id: 20140224-0627)
        • Checkstyle Plug-in 7.2.0.201611082205

Prerequisites:

      • Free DRAM for the a Docker Host VM >~ 4 GB
      • Docker Host is available, Jenkins is installed and a build process is configured. For that, perform all steps in part 1 to part 3 of this blog series (new: you now can skip part 1, if you wish)
      • Tested with 2 vCPU (1 vCPU might work as well)

Step 1: Start Jenkins in interactive Terminal Mode

Make sure that port 8080 is unused on the Docker host. If you were following all steps in part 1 of the series, you might need to stop cadvisor:

(dockerhost)$ sudo docker stop cadvisor

I assume that jenkins_home is already created, all popular plugins are installed and an Admin user has been created as shown in part 1 of the blog series. We start the Jenkins container with the jenkins_home Docker host volume mapped to /var/jenkins_home:

(dockerhost)$ cd <path_to_jenkins_home> # in my case: cd /vagrant/jenkins_home/
(dockerhost:jenkins_home)$ sudo docker run -it --rm --name jenkins -p8080:8080 -p50000:50000 -v`pwd`:/var/jenkins_home jenkins
Running from: /usr/share/jenkins/jenkins.war
...
--> setting agent port for jnlp
--> setting agent port for jnlp... done

Step 2: Open Jenkins in a Browser

Now we want to connect to the Jenkins portal. For that, open a browser and open the URL

<your_jenkins_host>:8080

In our case, Jenkins is running in a container and we have mapped the container-port 8080 to the local port 8080 of the Docker host. On the Docker host, we can open the URL.

localhost:8080

Note: In case of Vagrant with VirtualBox, per default, there is only a NAT-based interface and you need to create port-forwarding for any port you want to reach from outside (also the local machine you are working on is to be considered as outside). In this case, we need to add an entry in the port forwarding list of VirtualBox:
2016-11-30-19_22_22-regel-fur-port-weiterleitung

We have created this entry in part 1 already, but I have seen that the entries were gone again, which seems to be a VirtualBox bug. I have added it again now.

Log in with the admin account we have created in the last session:

2016-12-09-10_24_00-jenkins

Step 3: Code Analysis: Checkstyle

With Gradle, we can invoke the Checkstyle plugin as follows:

Step 3.1: Prepare Gradle for performing Checkstyle

Add to build.gradle:

apply plugin: 'checkstyle'

tasks.withType(Checkstyle) {
 ignoreFailures = true
 reports {
 html.enabled = true
 }
}

We have set ignoreFailures to true, since we do not want the Gradle build to fail for now. We are just interested in the Checkstyle reports for now.

We can download an example Checkstyle configuration file from the Apache Camel repository, for example:

git clone <yourprojectURL>
mkdir -p <yourprojectDir>/config/checkstyle/
curl https://raw.githubusercontent.com/apache/camel/master/buildingtools/src/main/resources/camel-checkstyle.xml > <yourprojectDir>/config/checkstyle/checkstyle.xml

Step 3.2 (optional): Test Checkstyle locally

If you have no Git and/or no Gradle installed, you may want to skip this step and directly proceed to the next step, so Jenkins is performing this task for you.

We can locally invoke CheckStyle as follows:

gradle check

Step 3.3: Configure Jenkins to invoke Checkstyle

Adding Gradle Checkstyle tests to be performed before each build is as simple as performing Step 4.1 and then adding “check” as a goal to the list of Jenkins Build Gradle Tasks:

On Dashboard -> Click on Project name -> Configure -> Build, add “check” before the jar task:

2016-12-28-15_33_58-github-triggered-build-config-jenkins

Click Save.

Now we verify the setting by either checking changed code into the SW repository (now is a good time to commit and push the changes performed in Step 4.1) or by clicking “Build now” -> Click on Build Link in Build History -> Console Output in the Project home:

2016-12-28-15_39_37-github-triggered-build-725-console-jenkins2016-12-28-15_40_08-github-triggered-build-725-console-jenkins

We have received a very long list of CheckStyle Errors, but, as configured, the build does not fail nevertheless.

At the same time, CheckStyle Reports should be available on Jenkins now:

The Links specified in the output are only available on Jenkins, but since Jenkins is running as a Docker container on Vagrant VM residing in

D:\veits\Vagrant\ubuntu-trusty64-docker_openshift-installer\jenkins_home

I need to access the files on

file:///D:/veits/Vagrant/ubuntu-trusty64-docker_openshift-installer/jenkins_home/workspace/GitHub%20Triggered%20Build/build/reports/checkstyle/

2016-12-28-15_48_11-index-von-d__veits_vagrant_ubuntu-trusty64-docker_openshift-installer_jenkins_ho

And on main.html we find:

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Wow, it seems like I really need to clean the code…

Step 4: Visualize the CheckStyle Warnings and Errors to the Developer

Usually Jenkins is not running as a Docker container on the Developer’s PC or Notebook, so he has no access to the above report files. We need to publish the statistics via the Jenkins portal. For that, we need to install the CheckStyle Jenkins plugin:

Step 4.1 (optional): Install the “Static Analysis Utilities”

Note: I have not tried it out, but I believe that this step is not necessary, since the next step will automatically install all plugins the Checksytle plug-in depends on.

On Jenkins -> Manage Jenkins -> Manage Plugins -> Available

In the Filter field, type “Static Analysis U”

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Check the checkbox of “Static Analysis Utilities” and Install without restart.

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Step 4.2: Install Checkstyle Plugin

On Jenkins -> Manage Jenkins -> Manage Plugins -> Available

In the Filter field, type “Checkstyle ” (with white space at the end; this will limit the number of hits):

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Check the checkbox of “Checkstyle Plug-in” and Install without restart.

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Step 4.3: Configure Checkstyle Reporting in Jenkins

On Dashboard -> <your Project> -> Configure -> Post-build Actions -> Add post-build action, choose

Publish Checkstyle analysis results

Now add the path, where Gradle is placing its result xml files:

**/build/reports/checkstyle/*.xml

2016-12-28-23_10_57-github-triggered-build-config-jenkins

And click Save.

Step 4.4: Manually trigger a new Build

On the Project page, click “Build now”, then click on the build and then “Console output”:

2016-12-28-23_17_16-github-triggered-build-726-console-jenkins

We now can see [CHECKSTYLE] messages after the build, telling us, that the reports were collected. Now, where can we see them?

Step 4.5: Review Checkstyle Statistics

On the Project page, choose Status:

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and click on Checkstyle Warnings on the left, or the warnings link in the center of the page, and we get a graphical representation of the Checkstyle statistics:

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When clicking on one of the File Links (MyRouteBuilder.java in this case), we can get an overview of the Warning types for this file:

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We choose the category Indentation and get details on the warnings:

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and after clicking on one of the links in the Warnings field, we see the java code causing the warning:

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Okay, Camel’s Checkstyle configuration does not like my style of grouping each route’s first line with a smaller indent than the rest of the route:

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And it does not seem to accept my style of putting the ; in a new line at the end of a route as seen by choosing the Whitespace category and then choosing an occurence:

2016-12-29-12_34_10-jenkins

I either need to change this style, or I need to adapte the checkstyle.xml configuration file to ignore those warnings.

Step 5: Improve Code Style

For the developer, it is very inconvenient to use the Jenkins Checkstyle messages from the console and match them with the code. We need something better than that: the Eclipse Checkstyle plugin.

Step 5.1: Install Eclipse Checkstyle Plugin via local Installation

Since the recommended installation via Marketplace did not work in my case (see Appendix A), I have followed some hints about a local installation found on StackOverflow:

Download Checkstyle from Sourceforge.

2016-12-30-13_54_36-add-repository

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In the next window, you are asked to specify some credentials we do not have. However, you can just ignore the window and click Cancel:

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->Cancel

Then the installation proceeds:

2016-12-30-14_04_17-install

2016-12-30-14_04_26-install

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Now I had to klick OK on security warnings twice:

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At the end, I had to restart Eclipse:

2016-12-30-19_09_15-software-updates

Now, the Checkstyle plugin is installed on Eclipse.

Step 5.2: Configure Project for Checkstyle Usage

The project in question must be enabled for Checkstyle usage by editing the Project Properties:

2017-01-07-23_14_44

Choosing the Checkstyle style. For now, let us choose the Google Checks in the drop-down list:

2017-01-07-23_18_41-properties-for-simple-restful-file-storage

Then confirm that the project is being re-built:

2017-01-07-23_18_50-rebuild-suggested

Now the code is more yellow than white, with many hints how to improve the code:

2017-01-07-23_28_00-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

However, the hints do not go away, if you correct the code. Do we need to rebuild again? Let us test:

2017-01-07-23_30_36-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

Google style does not like that there is no empty line before the package line (sorry, in German):

2017-01-07-23_29_57-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

So, let us add an empty line and save the file. However, the style warning does not change:

2017-01-07-23_31_53-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

Let us rebuild the project:

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Yes, after the re-build: the warning has disappeared:

2017-01-07-23_43_01-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

Step 5.3: Download and Create Custom Checkstyle Profile in Eclipse

In the Jenkins Checkstyle tests above, we have used following custom Checkstyle configuration file:

$ curl https://raw.githubusercontent.com/apache/camel/master/buildingtools/src/main/resources/camel-checkstyle.xml > <yourprojectDir>/config/checkstyle/checkstyle.xml

I.e. the Checkstyle file is found on <yourprojectDir>/config/checkstyle/checkstyle.xml

Correct:

2017-01-07-23_49_13-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

2017-01-07-23_52_04-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

2017-01-07-23_52_57-preferences

2017-01-07-23_55_39-check-configuration-properties

Step 5.4: Assign Custom Checkstyle Profile to the Project

To assign the new Checkstyle profile to the project, we change the project’s Checkstyle properties by

Project->Properties -> Checkstyle

2017-01-07-23_14_44

-> Choose new Checkstyle profile -> OK

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On the Rebuild suggested window -> Yes

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This works fine:

2017-01-18-02_29_51-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles-v2

In the code, we can see the Checkstyle warnings. To get more information on the specific Checkstyle warning, the warning text can be retrieved via the mouse over function on the left of the code line, or on the markers tab on the lower pane of Eclipse.

Step 5.5: Improve Code Style

Step 5.5.1: Change Code

In order to test, how the developer can improve the code style, let us replace some of the tabs by four spaces here:

2017-01-18-02_48_39-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

Save the file now.

Step 5.5.2: Update Maven

Unfortunately, the Checkstyle warnings update process is a little cumbersome for custom Checkstyle profiles, it seems: we need to

  1. save the changed file,
  2. update Maven and
  3. rebuild the project.

Let us update Maven first:

right-click the project folder in the left pane -> Maven -> Update Project -> OK

2017-01-18-02_54_032017-01-18-02_58_21-update-maven-project

Then all Checkstyle markers are gone (although I have not changed all occurrences of a tab):

2017-01-18-02_59_32-java-ee-simple-restful-file-storage_src_main_java_de_oveits_simplerestfulfiles

Step 5.5.3 Rebuild the Project

To get the Checkstyle warnings back, we need to rebuild the project:

Project -> Build Project

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Now we can see that some of the Checkstyle warnings are gone:

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Next time, you check in the code to the Gir repository, you will see that the number of Checkstyle warnings we get from Jenkins via Gradle will decrease…

Step 6: Verify Jenkins Results

Since we have improved the source code, we expect the Jenkins Checkstyle warnings to decrease. We can verify this by doing the following:

-> save, commit and push the improved code -> log into Jenkins -> check out the build process that is triggered by the code push (or we can manually trigger the build process by clicking project -> Build now)

On the dashboard, we will see, that the Checkstyle statistics have (very) slightly improved:

2017-01-18-04_37_06-github-triggered-build-jenkins-v2

On the upper right edge of the figure, the number of warnings is slightly lower. The code quality is far from being perfect, but we now have all tools and plugins needed to improve the situation.

After changing all tabs by 4 spaces each, the number of Checkstyle violations goes down by ~50%. That is a good start.

2017-01-19-22_51_58-github-triggered-build-jenkins-v2

Perfect, we have learned how to use the Checkstyle plugin for Eclipse in order to produce better code. And the Jenkins Checkstyle plugin allows us to admire the progress we make.

😉

thumps_up_3

Appendix A: Problems with installing Checkstyle Eclipse Plugin via Marketplace

Note: this way of installation is recommended officially, but has failed in my case. If you hit the same problem, try the local installation as described in step 5.1 above.

To improve the style, it would be much too cumbersome to click through all 360 style warnings, edit the Java code, build the Code and check again. It is much better to give the programmer immediate feedback of the warning within the IDE. I am using Eclipse, so I need to install the Checkstyle Eclipse plugin as follows:

Choose Eclipse -> Help -> Eclipse Marketplace

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Search for “Checkstyle” and click install:

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And then “confirm”:

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What is that?

2016-12-29-09_21_18-proceed-with-installation_

I install it anyway. At this point, it is hanging quite a while:

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so, let me get a morning coffee…

After approximately two minutes, I can see it to proceed to 4 / 15. Good sign.

After the coffee, I still see 4 / 15. Not a good sign:

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Meanwhile I am researching the steps needed for performance testing…

After 2 hours or so: 6/15

This will take all day!

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Some hours later, I checked again, and I have seen the following:

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I have confirmed, confirmed the license:

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And have pressed Finish.

Then software gets installed:

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I hope I will not break my good old Eclipse installation (it is installed locally, not in a virtual machine or container and it has ever worked better than any new version I have tested…).

After a two or three minutes:

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I have confirmed with “OK”…

Then I had been asked to restart Eclipse and I have confirmed.

Problem: however, Checkstyle is still not installed:

Help -> Eclipse Marketplace

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Let us try again by clicking “Install”:

2016-12-30-13_24_45-eclipse-marketplace

2016-12-30-13_24_59-proceed-with-installation_

This does not work

Workaround

Instead of installing Checkstyle via the Eclipse marketplace, better install the Eclipse Checkstyle Plugin via download (see Step 5.1)

Summary

In this blog post we have performed following tasks:

  1. Started Jenkins in a Docker container
  2. Installed the Checkstyle Gradle Plugin to create Checkstyle plugins as XML files
  3. Installed the Checkstyle Jenkins Plugin to summarize the XML files into graphical historic reports
  4. Installed the Checkstyle Eclipse Plugin to be able to improve the code
  5. Installed custom Checkstyle policies
  6. Visualized the Code Improvement
  7. were happy

All steps apart from the installation of the Eclipse Checkstyle plugin were quite straightforward. For the Eclipse Checkstyle installation, we had to revert back to a local download and installation method described in step 5.1: the installation via Eclipse marketplace had failed. At the end, we could reduce the number of Checkstyle warnings by 50% without much effort.

Further Reading

2

Jenkins Part 4.1: Functional Java Tests via JUnit


2016-11-30-18_19_38

You also think that functional tests are one of the most important ingredients for delivering high quality software? You share my opinion that we should help the developer automating this task in order to get comparable results and to receive meaningful trend reports?

I will cover functional tests here. Instructions on how to perform code quality tests and performance tests are in draft status and will be covered in the next two blog posts.

Any questions and/or comments are highly welcome.

Introduction

As a developer you try hard to deliver high quality software.

You hate searching for this nasty bug that had been introduced unnoticed days ago. Or was it weeks ago? By whom? In which code?

Manual functional and performance testing after each commited code change quickly becomes a NO-GO as the number of features is rising constantly. In this blog post, we will show, how Jenkins can help you with both: delivering high quality software and minimizing the time needed to find the cause of a bug.

How about …

  1. creating automated tests for each functionality and performance at different levels (end to end, and unit tests)
  2. running the automated tests after each code change
  3. keeping track of the test results

… in order to avoid any bad surprises late in the game?

Okay: for 1., the developer needs to create automated functional and perfomance tests; I guess, there is no way around this. Better do this even before writing the actual code. For 2. and 3., however, automation tools like Jenkins step in and can be of great help. The developers checks in the code and Jenkins can do the rest for you.

In the current  blog post, we will show how to integrate automated JUnit functional tests into a Jenkins build pipeline. We will see that JUnit tests can be invoked easily via Gradle (Okay, Maven is more popular than Gradle, I guess, but I like Gradle because of some advantages I have discussed here; However, just give me a hint in a comment to this blog and I will prioritize the creation of a Maven version of this blog post). The Jenkins JUnit plug-in will be used to

  1. display reports on single build runs as well as
  2. display trend analysis graphs like the following one I have borrowed from here:
2016-12-30-18_41_45-jenkins-junit-project-home-jpg-826x707
Source: http://nelsonwells.net/2012/09/how-jenkins-ci-parses-and-displays-junit-output/

In this and the next two blog posts, we plan to cover following quality gate measures:

  • Part 4.1: Functional Tests (this blog post): we will use Java JUnit tests performed before building the executable JAR. Jenkins will report the test trend
  • Part 4.2: Code Quality Tests (coming soon): we will use the Checkstyle Gradle plugin for reporting to which degree the code adheres to the Apache Foundations formal rules
  • Part 4.3: Performance Tests (planned): we will use JMeter for testing and reporting the performance trend performed after the Java build using external performance testers like JMeter

Older blogs of this series:

This blog post series about Jenkins build pipelines is divided into following parts:

    • Part 1: Installation and Configuration of Jenkins, loading Plugins
    • Part 2: Creating our first Jenkins job: GitHub download and Software build
    • Part 3: Periodic and automatically triggered Builds

What is Jenkins?

Jenkins is the leading open source automation server mostly used in continuous integration and continuous deployment pipelines. Jenkins provides hundreds of plugins to support building, deploying and automating any project.

2016-12-30-21_04_46

A typical workflow is visualized above: a developer checks in the code changes into the repository. Jenkins will detect the change, build (compile) the software, test it and prepare to deploy it on a system. Depending on the configuration, the deployment is triggered by a human person, or automatically performed by Jenkins. After each step, the developer is informed depending on the priorites defined.

For more information, see the introduction found in part 1 of this blog series.

Automated Functional Testing based on JUnit

In this blog post, we will show how we need to configure Gradle and Jenkins for automated JUnit testing and reporting. In order to build a quality gate, we will reverse the original order and perform the JUnit tests before we build the executable JAR file (we do not want to create JAR files that are not functional):

2016-12-28-12_50_23

Tools used

      • Vagrant 1.8.6
      • Virtualbox 5.0.20
      • Docker 1.12.1
      • Jenkins 2.19.3
        • JUnit Plug-in 1.19

Prerequisites:

      • Free DRAM for the a Docker Host VM >~ 4 GB
      • Docker Host is available, Jenkins is installed and a build process is configured. For that, perform all steps in part 1 to part 3 of this blog series
      • Tested with 2 vCPU (1 vCPU might work as well)

Step 1: Start Jenkins in interactive Terminal Mode

Make sure that port 8080 is unused on the Docker host. If you were following all steps in part 1 of the series, you might need to stop cadvisor:

(dockerhost)$ sudo docker stop cadvisor

I assume that jenkins_home is already created, all popular plugins are installed and an Admin user has been created as shown in part 1 of the blog series. We start the Jenkins container with the jenkins_home Docker host volume mapped to /var/jenkins_home:

(dockerhost)$ cd <path_to_jenkins_home> # in my case: cd /vagrant/jenkins_home/
(dockerhost:jenkins_home)$ sudo docker run -it --rm --name jenkins -p8080:8080 -p50000:50000 -v`pwd`:/var/jenkins_home jenkins
Running from: /usr/share/jenkins/jenkins.war
...
--> setting agent port for jnlp
--> setting agent port for jnlp... done

Step 2: Open Jenkins in a Browser

Now we want to connect to the Jenkins portal. For that, open a browser and open the URL

<your_jenkins_host>:8080

In our case, Jenkins is running in a container and we have mapped the container-port 8080 to the local port 8080 of the Docker host. On the Docker host, we can open the URL.

localhost:8080

Note: In case of Vagrant with VirtualBox, per default, there is only a NAT-based interface and you need to create port-forwarding for any port you want to reach from outside (also the local machine you are working on is to be considered as outside). In this case, we need to add an entry in the port forwarding list of VirtualBox:
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We have created this entry in part 1 already, but I have seen that the entries were gone again, which seems to be a VirtualBox bug. I have added it again now.

Log in with the admin account we have created in the last session:

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Step 3: Pre-Build JUnit Tests invoked by Gradle

In this step, we will invoke Gradle Tests before building the JAR. For that, we should verify locally that the Gradle tests are successful and then define a test Gradle task in the build process.

Step 3.1 (optional): Verify that Gradle Tests are successful

You can skip this test and directly let Jenkins do this for you. This may come handy, if you have not installed Git and/or Gradle locally.

Prerequisites

  • Your Java project has successful JUnit tests defined
  • Git is installed
  • The Project is cloned to a local directory
  • Gradle is installed

In order to test, whether the JUnit tests are successful, we can test those on a system with the project cloned (git, java and gradle must be installed):

(basesystem)$ gradle test
Starting a Gradle Daemon (subsequent builds will be faster)
Parallel execution is an incubating feature.
:compileJava UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:compileTestJava
warning: [options] bootstrap class path not set in conjunction with -source 1.6
1 warning
:processTestResources
:testClasses
:test

BUILD SUCCESSFUL

Total time: 29.9 secs

With that, we have verified that the command “gradle test”succeeds.

Note that the JUnit test must be designed in a way that they are independent of whether or not the JAR file is run in parallel. No simple way of running the executable JAR file in parallel to the execution of the JUnit tests seems to exist. In my case, I had to alter the JUnit tests to fulfill this prerequisite.

Step 3.2: Add Gradle test Task to Jenkins

As long as JUnit tests are defined in src/test of the project, adding Gradle tests to Jenkiny is as simple as adding “test” as a task to the list of Jenkins Build Gradle Tasks as follows:

On Dashboard -> Click on Project name -> Configure -> Build, add “task ” before the jar task:

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Click Save.

If you have made local code changes on the project, now is the best time to commit and push them to the Git repository. If you have followed the steps in part 3, then this will automatically trigger a build process, so you do not need to click on “Build now” in that case. Otherwise, click on “Build now” on the Jenkins project page (e.g. Dashboard -> click on project name -> “Build now”).

Now we observe the result by clicking on the build process, then -> “Console Output”:

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Don’t be confused by the blinking red ball on the upper left of the Console Output page: we see a BUILD SUCCESSFUL message and if we re-enter the same page, the ball is turned to static blue, indicating a successful build.

Step 4: Add JUnit Test Result Reporting to Jenkins

Now we will show how to add the JUnit test reports to the Jenkins build process.

Step 4.1: Install Jenkins JUnit Plugin

For Jenkins JUnit reporting, we need to install the JUnit Plug-in. For that, goto -> Jenkins Dashboard -> Manage Jenkins -> Manage Plugins -> Available -> Enter “JUnit Plugin” to the Find field -> Install

Note: If you do not find the plugin on the Available tab, search for it in the “Installed” tab.

You can install the plugin without reloading Jenkins.

Step 4.2: Configure Jenkins to collect and display the JUnit Test Results

In this step, we will configure Jenkins, so it will display the test results for individual builds as well as trend reporting. For that, navigate to:

Jenkins -> (choose Project) -> Configure -> Post-build Actions -> Publish JUnit test results report

2016-12-30-14_15_25-github-triggered-build-config-jenkins

Add

**/build/test-results/test/TEST-*.xml

to the “Test report XMLs” field, since this is the path, where Gradle is placing its JUnit test result reports (I have found the info here).

2016-12-30-14_18_51-github-triggered-build-config-jenkins

Now click Save.

Step 4.3: Verify JUnit individual Test Reporting

To test the Jenkins JUnit reporting feature, we trigger a clean build by adding “clean” to the Gradle tasks on Project -> Configure -> Build:

2016-12-30-17_43_59-github-triggered-build-config-jenkins

and clicking Save.

Then trigger a new build by clicking on Project -> Build now.

Then click on the Build Process, and then on Console output:

2016-12-30-17_48_38-github-triggered-build-731-console-jenkins

…scrolling down…

2016-12-30-17_50_01-github-triggered-build-731-console-jenkins

Do not be confused that the build process never seems to finish. Just click the Back to Project link:

Back to Project

On the Status page, we see that there were no failed tests:

2016-12-30-17_55_34-github-triggered-build-731-jenkins-v2

When we click on the Tests Result link on the left (or on the lower middle part on the Status page), we will see more details:

2016-12-30-17_58_25-github-triggered-build-731-test-results-jenkins-v2

We can see that we have had four tests (Create/Read/Update/Delete a file) and 100% of them were successful.

Step 4.3: Verify JUnit Test Trend Reporting

On the project’s Status page, a Test Trend graph is automatically added, as soon as there are two or more tests available. For that, click on “Build Now” on the left for a second time and click ENABLE AUTO REFRESH on the upper right. After the second build is complete, the (hopefully) blue Test Result Trend graph is showing up on the project status page:

2016-12-30-18_12_21-github-triggered-build-jenkins

The new blue graph shows that we had 4 successful tests in the last two builds.

Note: disregard the red Checkstyle Trend graph for now. This is something we will cover in the next blog post.

Step 5: Verify failed Test Reporting

Per default, Gradle build will fail, if one of the JUnit tests has failed, so it is building a strict quality gate. Will the test result be collected and reported nevertheless?

Let us test this now by breaking one of the JUnit tests by purpose. We have added an assert message that is expected to fail in one of the tests:

2016-12-30-19_27_46-java-ee-simple-restful-file-storage_src_test_java_de_oveits_simplerestfulfiles-v2

Now we commit and push the change to the SW repository:

$ git clone <Repository-URL>
$ cd <Repository Dir>
<perform the code changes here...>
$ git diff src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java
diff --git a/src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java b/src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java
index 684d30f..10200d5 100644
--- a/src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java
+++ b/src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java
@@ -115,6 +115,9 @@ public class SimpleRestfulFileStorageTests extends CamelSpringTestSupport {
 // mock expectations need to be specified before sending the message:
 mock.expectedBodiesReceived("File ttt created: href=http://localhost:2005/files/ttt");
 mock.expectedMessageCount(1);
+ ^M
+ // In order to break this test for Jenkins test reporting, we temporarily add a requirement that will fail:^M
+ mock.expectedMessageCount(2);^M

 template.sendBodyAndHeaders("direct:recipientList", body, headers);

$ git add src/test/java/de/oveits/simplerestfulfilestorage/SimpleRestfulFileStorageTests.java
$ git commit -m "Breaking a JUnit test by purpose for Jenkins reporting tests"
[jenkinstest 33655b9] Breaking a JUnit test by purpose for Jenkins reporting tests
 1 file changed, 4 insertions(+), 1 deletion(-)

olive@LAPTOP-P5GHOHB7 /d/veits/eclipseWorkspaceRecent/simple-restful-file-storage (jenkinstest)
$ git push
Counting objects: 9, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (9/9), 744 bytes | 0 bytes/s, done.
Total 9 (delta 4), reused 0 (delta 0)
remote: Resolving deltas: 100% (4/4), completed with 4 local objects.
To https://github.com/oveits/simple-restful-file-storage.git
 edb49f7..33655b9 jenkinstest -> jenkinstest

This will automatically trigger a new build (if you have followed part 3 of this series; otherwise just press “Build Now” on Jenkin’s project page).

We can see on the dashboard, that the build has failed:

2016-12-30-19_36_12-dashboard-jenkins

This was expected. Now let us click on the Project name, and we will see, what happened:

2016-12-30-19_37_40-github-triggered-build-jenkins

Perfect, that is exactly, what I wanted to achieve: On the Test Result Trend, we can see that we have performed 4 tests, one of which has failed.

Let us fix the failed test by commenting out (or removing) the wrong code again:

2016-12-30-19_40_01-java-ee-simple-restful-file-storage_src_test_java_de_oveits_simplerestfulfiles-v2

After

$ git add <file>
$ git commit -m "Fixed JUnit test again to test Jenkins JUnit trend report"
$ git push

The next build should be successful again and we can see in the trends graph that the failed test is fixed again:

2016-12-30-19_47_48-github-triggered-build-jenkins

thumps_up_3

Summary

In this blog post, we have shown

  1. How to add Java functional tests to the Jenkins build pipeline based on Gradle JUnit Plugin
  2. How to install the JUnit plug-in to Jenkins for report collection
  3. How to display JUnit test results for individual builds on the Jenkins portal
  4. How to display JUnit trend analysis on the Jenkins portal

The only challenge I have encountered is, that I had to re-write my JUnit tests in a way that they were successful when run stand-alone. Before they were successful only, if the executable JAR file was started manually before running the JUnit tests. This was resolved in a way specific to the framework used (Apache Camel in this case).

Coming Soon: Code Analysis Trend Analysis via Jenkins Checkstyle plugin

Further Reading