Verify Message Processor


The Verify feature provided by MUnit allows you to define verifications in order to validate a message processor’s calls.

For example, you can validate if a specific message processor has been called with a particular set of attributes a specific number of times.

Defining Verifications

When defining a verification, we are telling MUnit to fail a test if the verification is not successful.

You can define verifications over any message processor, even if you haven’t created a mock for it.

For the purposes of this document, we assume we are testing the following Mule code:

Studio Visual Editor

mock processor code to test

XML or Standalone Editor

<flow name="exampleFlow">
  <set-payload value="#['real_payload']" doc:name="Real Set Payload"/>

Defining Message Processor To Verify

When defining a verify, we make use of the verify-call message processor.

Studio Visual Editor

verify call

XML or Standalone Editor

<mock:verify-call messageProcessor="mule:set-payload" times="1"/>
Attribute Name Description


Describes which message processor we want to mock. The description takes the form {name-space}:{message-processor-name}. It supports regular expressions.


(Default = 1.) Defines the verification as successful if the message processor was called N and only N number of times.


Defines the verification as successful if the message processor was called a minimum of N number of times.


Defines the verification as successful if the message processor was called maximum of N number of times.

By default, the verify-call message processor assumes times=1 if no value is specified.
The attributes times, atLeast, atMost, are mutually exclusive. Only one should be used.

The messageProcessor attribute accepts regular expressions. You could create the same verification as follows:

Studio Visual Editor

verify call mule exp

XML or Standalone Editor

<mock:verify-call messageProcessor=".*:set-payload" times="1"/>

In the example above, we define a verification for a message processor named set-payload, disregarding which namespace the message processor belongs to.

The regular expression language is the same as Java.

Defining Verifications with Message Processor Attributes

The definition of a verification is based on matchers, that is, parameters that match features of the desired message processor. Defining a verification solely on the name of the message processor largely limits your scope and actions. For this reason, MUnit allows you to define a verify by defining matchers over the value of a message processor’s attributes.

Studio Visual Editor

verify call attribute

XML or Standalone Editor

<mock:verify-call messageProcessor="mule:set-payload">
    <mock:with-attribute whereValue="#['Real Set Payload']" name="doc:name"/>

You can define as many attributes as you deem necessary to make the verification as representative as possible. When defining an attribute, you do so by defining:

Attribute Name Description


The name of the attribute. This value is literal, it doesn’t support regular expressions.


The value that the attribute of the real message processor should contain. It accepts MEL expressions. If left as a literal, it assumes a string value.

If the attribute you wish the Verify message processor to match is similar to config-ref and resolves to an actual bean, you can use the MUnit MEL function getBeanFromMuleContext('bean_name'). This function inspects the Mule registry and returns the bean with the matching name if present. See Assertion for details.

Defining Verifications with Java Code

The example below shows how to reproduce the same behavior described above, using the MUnit Java API.

import org.junit.Test;
import org.mule.munit.common.mocking.Attribute;
import org.mule.munit.runner.functional.FunctionalMunitSuite;

public class TheTest extends FunctionalMunitSuite {

  public void test() {
    Attribute attribute = Attribute.attribute("name").
      ofNamespace("doc").withValue("Real Set Payload"); (1)

    verifyCallOfMessageProcessor("set-payload") (2)
    .ofNamespace("mule")                        (3)
    .withAttributes(attribute)                  (4)
    .times(1);                                  (5)

1 Define the real message processor attribute to match.
2 Define the message processor’s name to verify (accepts regular expressions).
3 Define the message processor’s namespace to verify (accepts regular expressions).
4 Set the message processor’s attribute defined in Note #1.
5 Define the amount of times (could also be atLeast(1) or atMost(1)).

INFO: Java does not provide default values for parameters times, atLeast or atMost, so you need to provide the value of the parameter that you use.

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