Apache Camel: Unit testing for file and http components

Question

I am fairly new to Camel & just managed to implement a use case as below with 2 routes which is using file & http components. Looking for some leads on writing junits for the same. Have tried some sample test case below based on the inputs that i found on the net. Not sure if that suffices. Appreciate your help!

• Implementation:

   @Override
   public void configure() throws Exception {
       // Global Exception Handling block
       onException(FileWatcherException.class).process(new Processor() {
           public void process(Exchange exchange) throws Exception {
               System.out.println("Exception handled");
           }
       }).to("file:C:/error?recursive=true").handled(true);
  
       // Actively listen to the input folder for an incoming file
       from("file:C:/input?noop=true&recursive=true&delete=true")
           .process(new Processor() {
               public void process(Exchange exchange) throws Exception {
                   String fileName = exchange.getIn().getHeader("CamelFileName").toString();
                   exchange.getIn().setHeader("fileName", fileName);
               }
           })
           // Call the Get endpoint with fileName as input parameter
           .setHeader(Exchange.HTTP_METHOD, simple("GET"))
           .toD("http://localhost:8090/fileWatcher?fileName=${header.fileName}")
           .choice()
               // if the API returns true, move the file to the outbox folder 
               .when(header(Exchange.HTTP_RESPONSE_CODE).isEqualTo(constant(200)))
                   .to("file:C:/outbox?noop=true&recursive=true")
                   .endChoice()
               // If the API's response code is other than 200, move the file to error folder
               .otherwise()
                   .log("Moving the file to error folder")
                   .to("file:C:/error?recursive=true")
                   .end();
  
       // Listen to the outbox folder for file arrival after it gets moved in the above step
       from("file:C:/outbox?noop=true&recursive=true")
           // Request Body for POST call is set in FileDetailsProcessor class
           .process(new FileDetailsProcessor())
           .marshal(jsonDataFormat)
           .setHeader(Exchange.HTTP_METHOD, simple("POST"))
           .setHeader(Exchange.CONTENT_TYPE, constant("application/json"))
           // Call the Rest endpoint with fileName & filePath as RequestBody
           .to("http://localhost:8090/fileWatcher")
           .process(new MyProcessor())
           .end();
   }
  

• Junit

    @Test
        public void checkFileWatcherFunctionality() throws Exception {
        context.getRouteDefinitions().get(0).adviceWith(context, new AdviceWithRouteBuilder() {
            @Override
            public void configure() throws Exception {
                // mocking all endpoints. **QUESTION** - Is this required?
                mockEndpointsAndSkip("http://localhost:8090:fileWatcher?fileName=loan.csv");
                mockEndpointsAndSkip("file:C:/processing");
                mockEndpointsAndSkip("file:C:/error");
                mockEndpointsAndSkip("http://localhost:8090:fileWatcher");
            }
        });
        context.start();
  
        // **QUESTION** - This is a GET call. Expecting only the HTTP status code from it. How to check that?
        getMockEndpoint("mock:http://localhost:8090:fileWatcher?fileName=abc.txt").expectedBodyReceived();
        // **QUESTION** - This is a POST call. How to send request body along? Expecting only the HTTP status code from it. How to check that?
        getMockEndpoint("mock:http://localhost:8090:fileWatcher").expectedBodyReceived();
        // **QUESTION** - Is this the right way to check?
        getMockEndpoint("mock:file:C:/processing").expectedFileExists("loan.csv");;
  
        template.sendBodyAndHeader("file:C:/inbound", "", Exchange.FILE_NAME, "loan.csv");
        // QUESTION - What can be asserted now?
  

  }

Also - How to write test cases for negative flow (exception scenario)? Looking for suggestions.

Answer 1

I have managed to draft the test case. Is this the right approach or can there be a better way? This might be more of an integration test i suppose.

The issue i see now is that the test case doesn't report at the end (success or failure), instead it keeps waiting for file arrival in the input folder. What am i missing?

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class FileWatcherRouteBuilderTest extends CamelTestSupport {

    @Autowired
    private TestRestTemplate restTemplate;
    
    @Override
    public RoutesBuilder createRouteBuilder() throws Exception {
        return new FileWatcherRouteBuilder();
    }

    @Test
    public void testFileCopy() throws Exception {
        template.sendBodyAndHeader("file:C:/inbound", "", Exchange.FILE_NAME, "abc.csv");
        
        // Call the GET endpoint 
        ResponseEntity<String> getResponse = restTemplate.getForEntity("http:localhost:8090/fileWatcher?fileName=abc.csv",
                String.class);
        assertTrue("Get call is unsuccessful", getResponse.getStatusCode().is2xxSuccessful());
        String response = getResponse.getBody();
        assertTrue(!response.isEmpty());
        
        // The file would have moved to output folder now.
        File targetFile = new File("C:/processing");
        assertTrue(targetFile.isDirectory());
        assertEquals(1, targetFile.listFiles().length);
        
        // Since we need to extract the file name, doing the below step
        Exchange exchange = consumer.receive("file:C:/processing");
        String fileName = exchange.getIn().getHeader("CamleFileName").toString();
        // RequestBody needed for POST call
        FileDetails fileDetails = new FileDetails(fileName, "C:/processing/"+fileName);
        HttpHeaders headers = new HttpHeaders();
        HttpEntity<FileDetails> request = new HttpEntity<FileDetails>(fileDetails, headers);
        // Call the POST endpoint
        ResponseEntity<String> postResponse = restTemplate.postForEntity("http://localhost:8090/fileWatcher", request, String.class);
        assertTrue("Post call is unsuccessful", postResponse.getStatusCode().is2xxSuccessful());
        
        // Asserting that after both the web service calls, the file is still available in the output folder
        assertEquals(1, targetFile.listFiles().length);
    }

}