Using Utility Classes From a Test

When developing test cases, you might want to use custom Java classes located in src/test/java. You can use Java classes through DataWeave or through Java Module.

When using custom classes, the package of the class must be exported in the mule-artifact.json file:

{
  "minMuleVersion": "4.x.x",
  "classLoaderModelLoaderDescriptor": {
    "id": "mule",
    "attributes": {
      "exportedPackages": [
        "com.example.test"
      ]
    }
  }
}

For example, assume that you want to use in an MUnit test a MyUtilClass.java class located in src/test/java/com/example/:

MyUtilClass

package com.example.test;

public class Helper {

  public static long getCurrentMillis() {
    return System.currentTimeMillis();
  }

}

Invoking Your Java Class Using DataWeave

To invoke static methods using DataWeave you must add the java! prefix to the package name of the class:

Using a class in DataWeave

<munit:test name="usingJavaInDW">
    <munit:behavior>
        <set-variable variableName="number" value="#[java!com::example::test::Helper::currentMillis()]" />
    </munit:behavior>
    <munit:execution>
        <flow-ref name="myFlow"/>
    </munit:execution>
</munit:test>

Invoking Your Java Class Using Java Module

To invoke a custom Java class using Java Module:

Ensure that Java Module is in your project:

Java Module dependency

<dependency>
    <groupId>org.mule.module</groupId>
    <artifactId>mule-java-module</artifactId>
    <version>${javaModule.version}</version>
    <classifier>mule-plugin</classifier>
    <scope>test</scope>
</dependency>

Use any of the Java Module’s operations.
For this example, invoke a static method of a class:

Using a class with the Java Module

<munit:test name="usingJavaInDW">
    <munit:behavior>
        <set-variable variableName="number" value="#[java!com::example::test::Helper::currentMillis()]" />
    </munit:behavior>
    <munit:execution>
        <flow-ref name="myFlow"/>
    </munit:execution>
</munit:test>