BPMN Driven Testing

Camunda Platform 7 / Camunda Platform 8 extension, which is able to generate test code based on an extended BPMN model.

The extension lets the developer focus on testing the business logic, rather than writing boilerplate code. The generated test code handles process instance start at any selected flow node and advances a process instance in case of wait states. Since the test code is generated, there is no need to deal with process definition keys and flow node IDs. Moreover any breaking changes (e.g. a user task becomes a service task) in the BPMN process will already be visible at design time as test compile errors.

A developer can solely focus on testing the actual implementation!

The extension consists of:

• Camunda Modeler plugin for a visual selection and the management of test cases
• Plugins for the generation of JUnit 5 based test code
  • Maven plugin / Gradle plugin for Camunda 7
  • Maven plugin 8 / Gradle plugin 8 for Camunda 8

⚠️ Version 0.10.0 supports Camunda 7.21 (Java 11+) and drops test code generation for JUnit 4. For older Camunda versions (Java 8+) and JUnit 4 support, please rely on version 0.9.0.

Features

• Visual test case selection
• Automatic path finding with
  • Support for embedded sub processes
  • Support for boundary events
  • BPMN collaborations with multiple expanded participants
  • Loop detection
• Test case validation and migration, when a BPMN process was changed - see docs
• Testing of arbitrary paths through a BPMN process

Camunda 7 features

• Generated test cases provide
  • Automatic handling of wait states
  • Call activity stubbing for isolated testing - see test
  • Fluent API to override default behavior, using *Handler
  • Multi instance (activity/embedded subprocess) support - see integration tests
• Spring/Spring Boot test support - see advanced-spring* under integration tests
• camunda-process-test-coverage extension support - see coverage* under integration tests

Camunda 8 features

• Generated test cases provide
  • Automatic handling of wait states
  • Call activity simulation for isolated testing - see test
  • Fluent API to override default behavior, using *Handler
  • Custom test code execution to handle and verify multi instances - see integration tests

How does it work?

Select test cases

After modeling, a developer uses the Camunda Modeler plugin to define suitable test cases by selecting a start and an end flow node. The modeler plugin finds all possible paths through the BPMN process. Each path can be added as a test case.

Optionally a test case can be named and described. Names and descriptions are reflected in the generated test code.

When the BPMN model is saved, the selected test cases are attached to the BPMN process in form of a custom extension element.

<bpmn:process id="order-fulfillment" isExecutable="true">
  <bpmn:extensionElements>
    <bpmndt:testCases>
      <bpmndt:testCase>
        <bpmndt:name>Happy Path</bpmndt:name>
        <bpmndt:path>
          <bpmndt:node>orderReceivedStartEvent</bpmndt:node>
          <bpmndt:node>checkAvailabilityUserTask</bpmndt:node>
          <bpmndt:node>itemsAvailableFork</bpmndt:node>
          <bpmndt:node>approveOrderSendTask</bpmndt:node>
          <bpmndt:node>prepareOrderUserTask</bpmndt:node>
          <bpmndt:node>deliverOrderUserTask</bpmndt:node>
          <bpmndt:node>orderFulfilledEndEvent</bpmndt:node>
        </bpmndt:path>
      </bpmndt:testCase>
    </bpmndt:testCases>
  </bpmn:extensionElements>

  <!-- ... -->
</bpmn:process>

Generate test code

To generate the code for the selected test cases, a developer must run the generator goal of the Maven or the generateTestCases task of the Gradle plugin.

The plugin finds all *.bpmn files under src/main/resources and looks for BPMN processes with a bpmndt:testCases extension element. Each test case will result in a JUnit 5 extension - in this example: generated.order_fulfillment.TC_Happy_Path.

For more information about plugin configuration and usage, please see:

• bpmn-driven-testing-maven-plugin
• bpmn-driven-testing-8-maven-plugin
• bpmn-driven-testing-gradle-plugin
• bpmn-driven-testing-8-gradle-plugin

Camunda 7: Implement tests

The generated test case class - in this example, TC_Happy_Path - must be imported and used as a JUnit 5 extension (a public or package-private field, which is annotated with @RegisterExtension).

@RegisterExtension
public TC_Happy_Path tc = new TC_Happy_Path();

Calling createExecutor() on the test extension, provides a fluent API, which is used to specify variables, business key and/or beans that are considered during test case execution. After the specification, execute() is called to create a new process instance and exeute the test case.

Moreover the default behavior of wait states and call activities can be adjusted using fluent APIs. For each applicable flow node a "handle*" method is generated - for example: handleCheckAvailabilityUserTask().

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.RegisterExtension;

import generated.order_fulfillment.TC_Happy_Path;

class OrderFulfillmentTest {

  @RegisterExtension
  TC_Happy_Path tc = new TC_Happy_Path();

  @Test
  void testItemsAvailable() {
    // fluent API for user task "checkAvailabilityUserTask"
    tc.handleCheckAvailabilityUserTask()
        .verify((pi, task) -> {
          // verify wait state
          pi.variables().containsEntry("customerId", 123);

          task.hasCandidateGroup("group-xyz");
        })
        .withVariable("available", true)
        .complete();

    // enrich and execute test case
    tc.createExecutor()
        .withBusinessKey("order-20210623-0001")
        .withVariable("customerId", 123)
        .withVariable("customerType", "NEW")
        .withBean("approveOrder", new ApproveOrderDelegate())
        .verify(pi -> {
          // verify state after execution
          pi.isEnded();
        })
        .execute();
  }
}

When a test is executed, the generated code handles the creation of the process engine as well as the process definition deployment. On the other hand, the test case execution handles the process instance start, applies the specified behavior and verifies that the process instance has passed the correct activities.

Camunda 8: Implement tests

The generated test case class - in this example, TC_Happy_Path - must be imported and used as a JUnit 5 extension (a public or package-private field, which is annotated with @RegisterExtension).

@RegisterExtension
public TC_Happy_Path tc = new TC_Happy_Path();

When calling createExecutor() on the test extension, a ZeebeTestEngine must be provided. The fluent TestCaseExecutor API allows to specificy variables, add additional resources, prepare the simulation of called processes and finally start a test case execution via execute().

Moreover the default behavior of wait states and call activities can be adjusted using fluent APIs. For each applicable flow node a "handle*" method is generated - for example: handleCheckAvailabilityUserTask() or handleApproveOrderSendTask().

import static com.google.common.truth.Truth.assertThat;

import org.example.ApproveOrderHandler;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.RegisterExtension;

import generated.order_fulfillment.TC_Happy_Path;
import io.camunda.zeebe.client.ZeebeClient;
import io.camunda.zeebe.process.test.api.ZeebeTestEngine;
import io.camunda.zeebe.process.test.assertions.ProcessInstanceAssert;
import io.camunda.zeebe.process.test.extension.ZeebeProcessTest;

@ZeebeProcessTest
class OrderFulfillmentTest {

  @RegisterExtension
  TC_Happy_Path tc = new TC_Happy_Path();

  ZeebeTestEngine engine;

  @Test
  void testItemsAvailable() {
    // fluent API for user task "checkAvailabilityUserTask"
    tc.handleCheckAvailabilityUserTask()
        .verify(piAssert -> {
          // verify wait state
          piAssert.hasVariableWithValue("customerId", 123);
        })
        .verifyCandidateGroups(groups -> assertThat(groups).containsExactly("group-xyz"))
        .verifyDueDate(dueDate -> assertThat(dueDate).isEqualTo("2023-02-17T00:00Z"))
        .verifyFormKey("checkAvailability")
        .withVariable("available", true)
        .complete();

    // fluent API for service task "approveOrderSendTask"
    tc.handleApproveOrderSendTask()
        .verifyRetries(3)
        .verifyType("approveOrder");

    var workerBuilder = client.newWorker().jobType("approveOrder").handler(new ApproveOrderHandler());

    // run worker, while test case is being executed
    try (var worker = workerBuilder.open()) {
      // enrich and execute test case
      tc.createExecutor(engine)
        .withVariable("orderId", "order-20210623-0001")
        .withVariable("customerId", 123)
        .withVariable("customerType", "NEW")
        .verify(piAssert -> {
          // verify state after execution
          piAssert.isCompleted();
        })
        .execute();
    }
  }
}

When a test case is executed, a ZeebeClient is used to deploy test case related resources (*.bpmn, *.dmn and/or *.form), create a process instance and interact with the ZeebeTestEngine by applying the specified behavior and verifying that the process instance has passed the correct BPMN elements.

More screenshots

Arbitrary paths

Test case validation