how to write unit test for spring integration xml code

Question

Im new to spring integration,I want to write unit test cases for my application. I'm working on an application where integration interface will be called by other system with XML input we transform the input XML using XSLT and will make a call to different system and the response will be sent to the caller.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:int="http://www.springframework.org/schema/integration"
    xmlns:task="http://www.springframework.org/schema/task"
    xmlns:int-jms="http://www.springframework.org/schema/integration/jms"
    xmlns:int-http="http://www.springframework.org/schema/integration/http"
    xmlns:int-xml="http://www.springframework.org/schema/integration/xml"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.2.xsd
        http://www.springframework.org/schema/integration/xml http://www.springframework.org/schema/integration/xml/spring-integration-xml-4.2.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd
        http://www.springframework.org/schema/integration/jms http://www.springframework.org/schema/integration/jms/spring-integration-jms-4.2.xsd
        http://www.springframework.org/schema/integration/http http://www.springframework.org/schema/integration/http/spring-integration-http-4.2.xsd
        http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration-5.0.xsd">

        <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
             <property name="locations">
                <list>
                    <value>application.properties</value>
                    <value>application-${spring.profiles.active}.properties</value>
                </list>
             </property>
        </bean>

        <bean id="MessagePrinter" class="com.oms.integration.messagelogger.MessagePrinter"></bean>

        <int:channel id="logIncommingCaptureRequestChannel"></int:channel>

        <int:channel id="transformedCaptureRequestToCardinalChannel"></int:channel>

        <int:channel id="incommingCaptureRequestToCardinal"></int:channel>

        <int:channel id="CaptureRequestToCardinalChannel"></int:channel>

        <int:channel id="logCaptureResponseFromCardinal"></int:channel>

        <int:channel id="transformCaptureResponseFromCardinal"></int:channel>

        <int:channel id="logTransformResponseFromCardinal"></int:channel>

        <int:channel id="ResponseFromCardinalToYantraChannel"></int:channel>



        <int-http:inbound-gateway request-channel="logIncommingCaptureRequestChannel" supported-methods="POST" path="/fp075" reply-channel="ResponseFromCardinalToYantraChannel"/>

        <int-http:outbound-gateway request-channel="CaptureRequestToCardinalChannel" url="${Paypal_Url}={data}" expected-response-type="java.lang.String" http-method="GET" reply-channel="logCaptureResponseFromCardinal">
            <int-http:uri-variable name="data" expression="payload"/>
        </int-http:outbound-gateway>

        <int:service-activator ref="MessagePrinter" input-channel="logIncommingCaptureRequestChannel" method="printIncommingCaptureRequestFromYantra" output-channel="incommingCaptureRequestToCardinal"></int:service-activator> 


        <int:service-activator ref="MessagePrinter" input-channel="transformedCaptureRequestToCardinalChannel" method="printTransformedCaptureRequestFromYantraToCardinal" output-channel="CaptureRequestToCardinalChannel"></int:service-activator> 

         <int:service-activator ref="MessagePrinter" input-channel="logCaptureResponseFromCardinal" method="printCaptureResponseFromCardinal" output-channel="transformCaptureResponseFromCardinal"></int:service-activator>

        <int:service-activator ref="MessagePrinter" method="printTransformedResponseFromCardinal" input-channel="logTransformResponseFromCardinal" output-channel="ResponseFromCardinalToYantraChannel"></int:service-activator>


        <int-xml:xslt-transformer
        input-channel="incommingCaptureRequestToCardinal"
        xsl-resource="classpath:/templates/FP075/DSW_XSLT_YANTRA_To_Paypal_Capture_Request_FP075.xslt"
        output-channel="transformedCaptureRequestToCardinalChannel"
        id="TransformIncommingCaptureRequest">
        <int-xml:xslt-param name="MsgType"
            value="${PP_Cardinal_MsgType_FP075}" />
        <int-xml:xslt-param name="Version"
            value="${PP_Cardinal_Version}" />
        <int-xml:xslt-param name="ProcessorId"
            value="${PP_Cardinal_ProcessorId}" />
        <int-xml:xslt-param name="MerchantId"
            value="${PP_Cardinal_MerchantId}" />
        <int-xml:xslt-param name="TransactionPwd"
            value="${PP_Cardinal_TransactionPwd}" />
    </int-xml:xslt-transformer>
        <int-xml:xslt-transformer
        id="transformCaptureResponse"
        input-channel="transformCaptureResponseFromCardinal"
        xsl-resource="classpath:/templates/FP075/DSW_XSLT_YANTRA_To_Paypal_Capture_Response_FP075.xslt"
        output-channel="logTransformResponseFromCardinal">
    </int-xml:xslt-transformer>
</beans>

Answer 1

Since you have there <int-http:inbound-gateway> and <int-http:outbound-gateway> I would suggest you to take a look into the Mock Spring MVC: https://docs.spring.io/spring/docs/current/spring-framework-reference/testing.html#spring-mvc-test-framework

The server side might be like this:

@RunWith(SpringRunner.class)
@WebAppConfiguration
@DirtiesContext
public class MyTests {

    @Autowired
    private WebApplicationContext wac;

    private MockMvc mockMvc;

    @Before
    public void setup() {
        this.mockMvc =
                MockMvcBuilders.webAppContextSetup(this.wac)
                        .build();
    }

For the client side you need to use something like MockMvcClientHttpRequestFactory abd inject it into the HttpRequestExecutingMessageHandler for that mentioned <int-http:outbound-gateway>.

So, in the end your main configuration is the same and all the flow structure remains untouched. You send mock requests via this.mockMvc.perform() and expect response after your flow processing.