Testing sub-flows in Mule

Question

I have started writing test cases to my Mule project.

I have written the functional test case for my Main Flows as follows.

public void testMainFlow_1() throws Exception{
     MuleClient client = muleContext.getClient();
            MuleMessage result = client.send(helloServiceAddress, fileAsString("SamplePayloads/input_Request.xml"), properties);
    assertNotNull("Null Result", result);           
    assertEquals(result.getPayloadAsString(), fileAsString("SampleResponses/sampleResponse.xml"));   

}

But how can I test my sub-flows. They don't have any end-points. So how can I pass payload to them and test it.

Given below is my flow config.

<flow name="main_flow" >
    ....
    ....
    <flow-ref  name="subflow_1" />
    ....
    ....
    <flow-ref  name="subflow_2" />
    ....
    ....
</flow>

<sub-flow name="subflow_1">
    ....
    <some-transformer ... />
    <out-bound call to web-service />
    <some-transformer ... />
    ....
</sub-flow>

<sub-flow name="subflow_2">
    ....
    <some-transformer ... />
    <out-bound call to web-service />
    <some-transformer ... />
    ....
</sub-flow>

Answer 1

Using the FunctionalTestCase it should be as simple as:

MessageProcessor subFlow = muleContext.getRegistry().lookupObject("subflow_1");
MuleEvent result = subFlow.process(getTestEvent("test_data"));

but it doesn't work.

For now, the best approach IMO consists in having a test config that contains flow wrappers for the sub-flows you want to test and load this test config alongside your main config in the FunctionalTestCase.

@genjosanzo's approach works too but it is based on associating the sub-flow with a pre-existing main-flow from test code itself. I personally think it would be stricter to create test flows instead.

Answer 2

By using the latest Mule version we can test sub-flow with the following script:

SubflowInterceptingChainLifecycleWrapper subFlow = getSubFlow("subflowName");
subFlow.initialise();

MuleEvent event = subFlow.process(getTestEvent(""));
MuleMessage message = event.getMessage();

assertEquals(expect, message.getPayload()); 

Answer 3

Invoking a subflow from a test case is fairly simple, this is an example:

    @Test
    public void invokeSubFlow() throws Exception {
        MessageProcessor mp = (MessageProcessor) muleContext.getRegistry()
                .lookupObject("subflow_2");
        FlowConstruct parentFlow = muleContext.getRegistry().lookupFlowConstruct("main_flow");
        ((FlowConstructAware) mp).setFlowConstruct(muleContext.getRegistry()
                .lookupFlowConstruct("subflow_2"));
        Lifecycle lc = (Lifecycle) mp;
        lc.initialise();
        lc.start();
        MuleMessage muleMessage = new DefaultMuleMessage("test", muleContext);
        MuleEvent event = new DefaultMuleEvent(muleMessage,
                MessageExchangePattern.REQUEST_RESPONSE,
                new DefaultMuleSession(parentFlow,muleContext));

        mp.process(event);
    }