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Camunda BPM Unit testing coverage generation using BPMNJS, Groovy, and Camunda Test Assertion Libraries. Also inlcudes a Java Bridge for use from pure Java Classes.
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Camunda Coverage Generation

A Unit testing tool for generating Camunda BPMN Coverage diagrams using BPMN.js

The tool uses Groovy and the Camunda Assertion framework.

How it works

The coverage generation helpers provide easy to use methods to take "Coverage Snapshots" at any point during a unit test.

Each snapshot generates "Coverage Data" which is used to generate HTML files in the build target folder.

Example output

Initial Parent Process:


Call 1 Sub Process:


Finished Parent Process:


Green = Completed

Blue = Unfinished/Still Active

Grey Box with Number = Occurrence Count (Used to show where activity's have looped/executed multiple times.

Spock Framework Report Example:



  1. Groovy is required to use these helpers for generating coverage reports
  2. Camunda History logging should be set to "Full". The Camunda History service is used to query the Camunda DB for the various data needed to generate coverage.


The following coverage items are currently covered by this tool:

Coverage Item Notes
Finished Activity Instances Shows which activities were successfully executed and completed.
Unfinished Activity Instances Shows which activities remained active; this means the activities were started, but did not complete, and did not throw a error
Finished Sequence Flows Shows sequence flow completion, allowing tracking of specific sequence flow pathways
BPMN Model Async Flag: Before/After Async, Exclusive Shows which activities have a Async Before, Async After, and Exclusive configuration in the BPMN Model
User Tasks Async Flag Shows a marker for each User Task to indicate the User Tasks async nature; this is a different marker than the BPMN Model Async Flag
External Task Async Flag Shows a marker for each Service Task with a 'External' implementation, to indicate the Service Task's async nature; this is a different marker than the BPMN Model Async Flag
Receive Task Async Flag Shows a marker for each Receive Task, to indicate the Task's async nature; this is a different marker than the BPMN Model Async Flag
Intermediate Catch Events Async Flag Shows a marker for each Intermediate Catch Event. to indicate the event's async nature; this is different than the BPMN Model Async Flag
Variable instance activity Shows a icon where activities have created, modified, or deleted a Variable during execution
Activity Occurrence/Instance Counts Shows Counts under each executed activity to show the number of times a activity was executed. Typically used to visualize loops and multi-instance scenarios within a BPMN.

Each coverage item can have its look-and-feel modified through a change in the rendering templates: head.html, body.html, and footer.html.


Method Usage Notes
getSequenceFlowFileName() Returns the file name defined in the path to the SequneceFlowListener javascript file. Expects that the javascript file will be located within at least 1 folder. See the Spock Framework Example.
getSequenceFlowListenerScript() Returns a InputStream of the Listener Script that can then be added into the deployment. See the Spock Framework example.
addSequenceFlowListeners('some/path/to/file.bpmn') Processes a BPMN file to add Listeners to each sequence flow, and returns a Model Instance to be used in the deployment See the Spock Framework Example.
coverageSnapshot(processInstance, 'Coverage Title') Generates a coverage snapshot: this will query the Process Instance's BPMN Model and the Camunda DB for all relevant data required to generate the Coverage Data. This method can be called multiple times during a test, allow coverage generation throughout the process lifecycle. Only the process instance is required. The Title is optional and only used to set a custom file name of the .html file generated by saveCoverageSnapshots()
saveCoverageSnapshots() Generates BPMN.js .html coverage files for each Coverage Snapshot. Saves to the defined output directory; typically: target/bpmn-converage/[]/. The snapshots will be saved in the order they were generated with file names formats of: If coverageName was provided: [index]_[coverageName].html or if no coverage name was provided: [index].html. Examples: 0_snap.html, 1_anotherSnap.html, 2.html. Notice how you can use titles and no-titles as you see fit. See the Spock Framework Example.

The coverage generation tool using Groovy Traits to inject the functions. Within your Groovy class of your Unit Test add the following traits CoverageBuilder and SequenceFlowHistory There is also a Java bridge for use within Java JUnit tests for when not using Groovy Unit Testing.

Such as:

import io.digitalstate.camunda.coverage.bpmn.CoverageBuilder
import io.digitalstate.camunda.coverage.bpmn.SequenceFlowHistory

CallActivitySingleFeatureSpec extends Specification implements CoverageBuilder, SequenceFlowHistory{


How to install

Add JitPack as a repository source in your build file.

If you are using Maven, then add the following to your pom.xml


This snippet will enable Maven dependency download directly from

Then add the following dependency:


Usage example with Spock Framework

class CallActivitySingleFeatureSpec extends Specification implements CoverageBuilder, SequenceFlowHistory {

    @Shared ProcessEngineRule processEngineRule = new ProcessEngineRule('camunda_config/camunda.cfg.xml')
    @Shared String deploymentId

    def setupSpec(){
        // Set a Custom CSS File:
        // CssGeneration myCss = new CssGeneration()
        // myCss.setCssFile('/bpmn1.css')
        // setCssGeneration(myCss)
        def deployment = repositoryService().createDeployment()
                .addInputStream(getSequenceFlowFileName(), getSequenceFlowListenerScript())
                .addModelInstance('CallActivityCoverage.bpmn', addSequenceFlowListeners('bpmn/CallActivityCoverage.bpmn'))
                .addModelInstance('CallActivityCoverage2.bpmn', addSequenceFlowListeners('bpmn/CallActivityCoverage2.bpmn'))
        deploymentId = deployment.getId()
        println "Deployment ID: '${deploymentId}' has been created"

    def 'Manage CallActivityCoverage1'() {
        when: 'Setting up variables'
        def json = S("{\"customer\": \"Kermit\"}")
        def startingVariables = [
                'json': json

        and: 'We start the CallActivityCoverage process definition'
        ProcessInstance callActivityCoverage1ProcessInstance = runtimeService().startProcessInstanceByKey('CallActivityCoverage')

        then: 'Process is Active and waiting for user task completion'

        then: 'The current process variables are equal to the starting variables'
        def processVariables = runtimeService().getVariables(callActivityCoverage1ProcessInstance.getProcessInstanceId())
        assertThat(processVariables == startingVariables)

        then: 'The process instance should be waiting for the Call Activity to Complete'

        coverageSnapshot(callActivityCoverage1ProcessInstance, 'some1')

        and: 'get the called called process instance'
        HistoricActivityInstance callActInstance = historyService().createHistoricActivityInstanceQuery()

        ProcessInstance callActivityCoverage2ProcessInstance = calledProcessInstance(processInstanceQuery().processInstanceId(callActInstance.getCalledProcessInstanceId()))

        then: 'CallActivityCoverage2 is running'

        then: 'CallActivityCoverage2 is waiting at the User Task'

        then: 'Complete the User Task'

        then: 'CallActivityCoverage2 has completed'

        coverageSnapshot(callActivityCoverage2ProcessInstance, 'some2')

        then: 'CallActivityCoverage1 has ended'


    def cleanupSpec() {

                true, // cascade
                true, // skipCustomListeners
                true) // skipIoMappings
        println "Deployment ID: '${deploymentId}' has been deleted"


Sequence Flow Listener

Sequence Flows (The Arrow Lines between activities) are not tracked by the Camunda history engine. Therefore, we must inject a listener on each sequence flow.

A helper is provided that will take a BpmnModelInstance and add the listener to each sequence flow.

The helper is addSequenceFlowListeners() which can pass a path to a BPMN path

An example setup of a spock framework unit test:

def setupSpec(){

def deployment = repositoryService().createDeployment()
                                    .addInputStream(getSequenceFlowFileName(), getSequenceFlowListenerScript())
                                    .addModelInstance('CallActivityCoverage.bpmn', addSequenceFlowListeners('bpmn/conditionalstart/CallActivityCoverage.bpmn'))
                                    .addModelInstance('CallActivityCoverage2.bpmn', addSequenceFlowListeners('bpmn/conditionalstart/CallActivityCoverage2.bpmn'))
deploymentId = deployment.getId()
println "Deployment ID: '${deploymentId}' has been created"

Notice the line .addInputStream(getSequenceFlowFileName(), getSequenceFlowListenerScript()).

The getSequenceFlowFileName() will return the filename and extension of a helper javascript file. This javascript file can be retrieved as a InputStream using getSequenceFlowListenerScript().

There are multiple ways to leverage this javascript file depending on your testing needs. For example you can use the .addClasspathResource() and directly access the resource or can make it part of the database deployment


If you want to work with this project, compile your own jar locally, or just modify stuff and test it out you can easily do so:

in a terminal in the root of the project, run:

./mvnw clean test which will download the needed dependencies and build the test project. Check the target folder after build to see the bpmn-coverage folder with the .html files.

Note: on first load there will be some extra downloads that occur, where the "Maven Wrapper" is downloading or building the required Jar. This is so you do not need to have Maven installed.

Customizations to CSS and JS

Often you will want to customize the CSS and Javascript rendering of your coverage snapshots. You can easily do this for each use of saveCoverageSnapshots().

// Set a Custom CSS File:
CssGeneration myCss = new CssGeneration();

// Set a Custom JS File:
JsGeneration myJs = new JsGeneration();

The CoverageBuilder exposes a setCssGeneration() and a setJsGeneration() method that allow you to customize which CssGeneration and JsGeneration class instances are used during the generation of the html files.

You can change/set your CSS and JS Files at any point and continue to change them after each save to disk. This allows you to have different visuals of the same BPMN snapshot if you wish (such as various views of state, sync and async, etc).

See the tests for commented-out examples.

Using the Coverage Builder with JUnit / Pure Java

As of 0.6, a groovy class that implements the CoverageBuilder trait has been added: io.digitalstate.camunda.coverage.bpmn.CoverageBuilderJavaBridge.class.

This class can easily be used to implement coverage reports without having to write a test in Groovy.

Example of the default JUnit template example provided by Camunda but with Coverage Generation:

package coveragetest;

import io.digitalstate.camunda.coverage.bpmn.CoverageBuilderJavaBridge;
import org.camunda.bpm.engine.runtime.ProcessInstance;
import org.camunda.bpm.engine.test.Deployment;
import org.camunda.bpm.engine.test.ProcessEngineRule;

import static org.camunda.bpm.engine.test.assertions.ProcessEngineTests.*;

import org.junit.Rule;
import org.junit.Test;

 * @author Daniel Meyer
 * @author Martin Schimak
public class SimpleTestCase {

    public ProcessEngineRule rule = new ProcessEngineRule("camunda_config/camunda.cfg.xml");
    CoverageBuilderJavaBridge coverageBuilder = new CoverageBuilderJavaBridge();

    @Deployment(resources = {"testProcess.bpmn"})
    public void shouldExecuteProcess() {

        // Set a Custom CSS File:
        // CssGeneration myCustomCSS = new CssGeneration();
        // myCustomCSS.setCssFile("/bpmn1.css");
        // coverageBuilder.setCssGeneration(myCustomCSS);

        // Given we create a new process instance
        ProcessInstance processInstance = runtimeService().startProcessInstanceByKey("testProcess");
        // Then it should be active
        // And it should be the only instance
        // And there should exist just a single task within that process instance

        // When we complete that task
        // Then the process instance should be ended


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