Author: Abhishek Bathwal

Whenever we write Munit Test cases for any flow, coverage is one of the very important components which we have to take care. But due to error handling, it becomes difficult to get the required coverage.

To meet the coverage threshold we have two options:

  1. Ignoring the Error Handling flow
  2. Writing test cases for Error handling

Note: This blog will have a detailed solution on writing the test cases for Error Handling.  

  1. Ignoring the Error Handling flow

For ignoring a flow, we can use the ignore plugins in the POM. So when we execute the Munit the particular flow will be ignored and we will get a better coverage report.

<plugins>
  <plugin>
    <groupId>com.mulesoft.munit.tools</groupId>
    <artifactId>munit-maven-plugin</artifactId>
    <configuration>
      ...
      <coverage>
        <ignoreFlows>
             <ignoreFlow>flow-name</ignoreFlow>
        </ignoreFlows>
     </coverage>
      ...
    </configuration>
  </plugin>
</plugins>

But the Munit Studio has a limitation with this. The Munit Coverage report does not reflect this in the report. To get the exact coverage percentage please follow the report from the console or execute the test cases from the Command prompt.

Script for cmd execution:

mvn test or mvn clean test or mvn test -X
  1. Writing test cases for Error handling

We have a simple flow with one resource  and one error handling block as APIKIT:BAD_REQUEST.

The Transform Message of the AKIKIT:BAD_REQUEST contains a payload with a message and variable with httpStatus (We can have any custom message in the payload as per requirement).

Now, we will write a test case for the main flow which contains the error propagate block.

It contains a Mock component as Behavior, a Flow reference as Execution step and an Assert Equal component in Validation.

The Flow Reference will refer to the main flow:

Next we are going to configure the mock where we will Mock the APIKIT router and define the Error Typeid in the Error ta. Also, in the suite flow configuration we need to define the Expected error type (These two steps are very important because on the basis of these only the test case for error propagate will work).

Mock Component: 

Flow Configuration:

For Assert That, the assertion can be on the basis of payload or httpStatus code. It completely depends on the user. For our application, we’ve selected httpStatus for validation.

As all the configurations are done and we have set up the test flow, we will now execute the test case.

Console Result:

= Tests run: 1 - Failed: 0 - Errors: 0 - Skipped: 0 - Time elapsed: 0.18 sec

Munit Studio Result:

Munit Coverage Report:

Note: As we have not written any test case for the post:\demo resource flow and only for Main flow, so the coverage for demo resource flow is 0% and for Main Flow is 100%.

Once the test case is executed, the part which comes under the success test execution is marked with a green check which indicates that the test cases for those components are done successfully. 

In similar way, we can write test cases for other Error Types as well.

Sample Munit Code:

<?xml version="1.0" encoding="UTF-8"?>
<mule
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:munit="http://www.mulesoft.org/schema/mule/munit"
    xmlns:munit-tools="http://www.mulesoft.org/schema/mule/munit-tools"
    xmlns="http://www.mulesoft.org/schema/mule/core"
    xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
	xsi:schemaLocation="
		http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
		http://www.mulesoft.org/schema/mule/munit http://www.mulesoft.org/schema/mule/munit/current/mule-munit.xsd
		http://www.mulesoft.org/schema/mule/munit-tools  http://www.mulesoft.org/schema/mule/munit-tools/current/mule-munit-tools.xsd">
    <munit:config name="demo-test-suite.xml" />
    <munit:test name="demo-test-suite-demo-main-BAD_REQUEST-Test" doc:id="8b6ba2d1-4696-43de-a07b-d854f4e5e2b6" description="Test" expectedErrorType="APIKIT:BAD_REQUEST">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:BAD_REQUEST" doc:id="6e68f7aa-75bf-4f15-93be-0c451375e9d9" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:BAD_REQUEST" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow-ref to demo-main" doc:id="9df72122-506f-4759-aa24-134f8341b782" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="93698feb-de93-40b2-bc11-44739ad55c00" actual="#[vars.httpStatus]" expected="#[400]"/>
        </munit:validation>
    </munit:test>
    <munit:test name="demo-test-suite-demo-main-NOT_FOUND-Test" doc:id="8cfe733b-449f-4df1-b09d-06d79f63d8fb" description="Test" expectedErrorType="APIKIT:NOT_FOUND">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:NOT_FOUND" doc:id="ff561c10-4a97-456a-af92-29c144363d3d" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:NOT_FOUND" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow Reference" doc:id="5079c1a2-74ff-4591-ac6d-840b8b15e78a" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="596dd171-6c28-415b-8a9d-8b9152f62cb4" actual="#[vars.httpStatus]" expected="#[404]"/>
        </munit:validation>
    </munit:test>
    <munit:test name="demo-test-suite-demo-main-METHOD_NOT_ALLOWED-Test" doc:id="635ace96-1503-40ce-8de3-13e7411726c8" description="Test" expectedErrorType="APIKIT:METHOD_NOT_ALLOWED">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:METHOD_NOT_ALLOWED" doc:id="894571a7-42b9-4caf-9be4-3c16d9cfa0f6" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:METHOD_NOT_ALLOWED" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow-ref to demo-main" doc:id="b57e4856-e333-4b45-bb01-c234f8e5e9f9" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="493307c6-825b-4652-a61e-2973332a972f" actual="#[vars.httpStatus]" expected="#[405]"/>
        </munit:validation>
    </munit:test>
    <munit:test name="demo-test-suite-demo-main-NOT_ACCEPTABLE-Test" doc:id="1bec6f0d-01ed-43b2-bf39-8736cbf5e590" description="Test" expectedErrorType="APIKIT:NOT_ACCEPTABLE">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:NOT_ACCEPTABLE" doc:id="3a329baf-99df-49fb-8b18-636dc5316973" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:NOT_ACCEPTABLE" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow Reference" doc:id="a46ee38a-13b0-431d-ab94-6fafa8492ee2" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="35aff4f1-30e8-4cda-b71e-736d0b279a98" actual="#[vars.httpStatus]" expected="#[406]"/>
        </munit:validation>
    </munit:test>
    <munit:test name="demo-test-suite-demo-main-UNSUPPORTED_MEDIA_TYPE-Test" doc:id="d8454189-e4e1-4375-b585-0a999a837619" description="Test" expectedErrorType="APIKIT:UNSUPPORTED_MEDIA_TYPE">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:UNSUPPORTED_MEDIA_TYPE" doc:id="f41c89d8-b712-47a4-b358-ef8cb3ba086c" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:UNSUPPORTED_MEDIA_TYPE" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow-ref to demo-main" doc:id="92675038-645a-4a98-b897-06845a04e6e3" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="5065fd21-8f7f-4d1f-a6d5-042f40aefbfd" actual="#[vars.httpStatus]" expected="#[415]"/>
        </munit:validation>
    </munit:test>
    <munit:test name="demo-test-suite-demo-main-NOT_IMPLEMENTED-Test" doc:id="e2cbf56e-ee66-41cc-82be-333dd1eb292c" description="Test" expectedErrorType="APIKIT:NOT_IMPLEMENTED">
        <munit:behavior >
            <munit-tools:mock-when doc:name="Mock when APIKIT:NOT_IMPLEMENTED" doc:id="aeb6b8f2-7488-4608-b591-ee22331b85f0" processor="apikit:router">
                <munit-tools:with-attributes >
                    <munit-tools:with-attribute whereValue="demo-config" attributeName="config-ref" />
                </munit-tools:with-attributes>
                <munit-tools:then-return >
                    <munit-tools:error typeId="APIKIT:NOT_IMPLEMENTED" />
                </munit-tools:then-return>
            </munit-tools:mock-when>
        </munit:behavior>
        <munit:execution >
            <flow-ref doc:name="Flow-ref to demo-main" doc:id="bd189bb8-d517-448c-bcdf-fe043190d0a0" name="demo-main"/>
        </munit:execution>
        <munit:validation >
            <munit-tools:assert-equals doc:name="Assert equals" doc:id="302886a9-6dc6-4c96-920f-0d6f4100aa9c" actual="#[vars.httpStatus]" expected="#[501]"/>
        </munit:validation>
    </munit:test>
</mule>

Happy Learning!

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