I have a class Component which creates two objects from other classes JMSConnector and AppiaConnector and links both of them.
I have a method that reads the status of both objects and return a combined value.
Here is the code:
Problem I am facing when testing this method is I have no way of injecting mocks of appiaConnector and jmsConnector to test the behaviour of this method.
For example I tried this:
#RunWith(MockitoJUnitRunner.class)
public class ComponentTest {
#Mock
JMSConnector jmsConnector;
#Mock
AppiaConnector appiaConnector;
Component component = new Component();
#Test
public void testGetStatus() {
given(jmsConnector.getStatus()).willReturn(true);
given(appiaConnector.getStatus()).willReturn(true);
// this is what I want... but I can't dynamically inject these mocks into component ???
assertTrue(component.getStatus());
}
}
Is there a way that I can achieve this, or should I use stubs? (which seems an overkill for such a small method)
You can pass them as parameters instead of creating them inside the method.
public Component(AppiaConnector appiaConnector, JMSConnector jmsConnector) {
// do your status check
}
Now if in your production code, you don't want to inject them, you can always create another constructor with no parameters. That way you keep your code the same but gain in testing flexibility
public Component() {
this(new AppiaConnector(), new JMSConnector());
}
Component(AppiaConnector appiaConnector, JMSConnector jmsConnector) {
// do your status check
}
Related
Using Junit version 5.9.2 I am trying to programmatically add parameter resolvers extension for a test class constructor with a #TestTemplate annotation.
I am trying to add the extensions programmatically using #RegisterExtension.
Example:
public class MyTestClass {
#RegisterExtension
static final TestDependencyResolver resolverExt = new TestDependencyResolver(/*...*/);
private final TestDependency dependency;
public MyTestClass(TestDependency dependency) {
this.dependency = dependency;
}
#TestTemplate
#ExtendWith(SomeContextProvider.class)
void test() {
//...
}
}
I have tried:
making resolverExt field non static
Movine #ExtendWith(SomeContextProvider.class) to class level
And other possible combinations of 1 and 2.
In all cases the ctor parameter dependency is not injected and TestDependencyResolver::resolveParameter is not called, which to my understanding means the object was created without/before registering TestDependencyResolver, please correct me if I am wrong.
Is what I am trying to achieve possible? thanks.
Turns out the issue was not Junit5 but TestTemplateInvocationContextProvider I was using.
I used PactVerificationInvocationContextProvider which seems to have a bug and throws NullPointerException when resolving Ctor params, I have opened an issue for it if you want more details.
I am trying to use Ajax to call a handler in my Razor page that returns the result of a ViewComponent, however when I try the code below, it says:
Non-invocable member "ViewComponent" cannot be used like a method.
public IActionResult OnGetPriceist()
{
return ViewComponent("PriceList", new { id= 5 });
}
When using MVC, the Controller base class includes a ViewComponent method, which is just a helper method that creates a ViewComponentResult for you. This method does not yet exist in the Razor Pages world, where instead you use PageModel as the base class.
One option to work around this is to create an extension method on the PageModel class, that would look something like this:
public static class PageModelExtensions
{
public static ViewComponentResult ViewComponent(this PageModel pageModel, string componentName, object arguments)
{
return new ViewComponentResult
{
ViewComponentName = componentName,
Arguments = arguments,
ViewData = pageModel.ViewData,
TempData = pageModel.TempData
};
}
}
Apart from it being an extension method, the code above is just ripped out of Controller. In order to use it, you can call it from your existing OnGetPriceList (typo fixed) method, like this:
public IActionResult OnGetPriceList()
{
return this.ViewComponent("PriceList", new { id = 5 });
}
The key to making it work here is to use this, which will resolve it to the extension method, rather than trying to invoke the constructor as a method.
If you're only going to use this once, you could forego the extension method and just embed the code itself inside of your handler. That's entirely up to you - some people might prefer the extension method for the whole separation-of-concerns argument.
I am using dotnet core and have created a custom exception filter to handle exceptions. The problem i face is that in case of exceptions , the onException method in the custom filter is called two times. Below is the code :
public class CustomExceptionFilter : ExceptionFilterAttribute
{
public override void OnException(ExceptionContext context)
{
// Code
base.OnException(context);
}
}
Controller Code is :
[CustomExceptionFilter]
public class MyController : Controller
{
// Raise an exception in any apis
}
Why onException is called two times?
Using Visual Studio I created a new Asp.Net Core Web Application and used the standard Web Application Template. Then I added the CustomExceptionFilter class and added the [CustomExceptionFilter] attribute to the HomeController and threw and exception inside it's Index method:
[CustomExceptionFilter]
public class HomeController : Controller
{
public IActionResult Index()
{
throw new Exception("Time to bail!");
return View();
}
}
Finaly, I set a breakpoint on this line in the CustomExceptionFilter:
base.OnException(context);
And ran the website. The debugger stops on the throw of course, and then it stops on the line with the breakpoint. The breakpoint is only hit once. So my setup verifies the expected behavior.
Troubleshooting
In the past, I have ran into similar situations where something that should only be called once is called twice and it's almost always turned out to be because a second http request came in that I wasn't expecting. So it really was only being called once per http request. One way to check on that is to look at the path and query in the method which you can do as indicated below:
public class CustomExceptionFilter : ExceptionFilterAttribute {
public override void OnException(ExceptionContext context) {
//set breakpoing on the following line to see what the requested path and query is
string pathAndQuery = context.HttpContext.Request.Path + context.HttpContext.Request.QueryString;
// Code
base.OnException(context);
}
}
Another scenario that can cause this is adding the attribute in two places:
I had this:
config.Filters.Add( new StandardExceptionHandlingAttribute() );
AND this:
[StandardExceptionHandling]
public async Task<int?> ....
public static ResponseBean call(Bean bean) throws Exception {
// statements...
IgnoreCall.ignoreMethodCall(bean);
// statements...
// return
}
With the code snippet above, is it possible to test the method ignoring invocation of IgnoreCall.ignoreMethod(Bean) without needing to place the entire statement under a boolean condition?
Here's the unit test code snippet:
#RunWith(PowerMockRunner.class)
#PrepareTest
public ClassHelperTest {
#Test
public void testCall() throws Excpetion {
// stubbing...
ResponseBean responseBean = ClassHelper.call(bean);
// verify/ies
// assert/s
}
}
Notes:
Refactoring ClassHelper.call(Bean) should be avoided. Even with a bad OO design, refactoring is costly.
Method signature is locked unless another pattern is applicable for replacement.
Tried using Mockito.when and PowerMockito.when on the target static method, stubbing didn't work on run-time debug.
As your comments indicate that changing your production code is not possible, you "simply" have to dive into the static-mocking aspects of PowerMock; as outlined here for example.
Basically you need to enable IgnoreCall for static mocking; and then you make calls to ignoreMethodCall() a no-op.
But as you keep asking: the core problem with your question is the fact that you want to mock out a static method that is void. I have a complete example below, but before that some explanations.
The point is: you call a method for two reasons:
It has a side effect
It returns a value, and maybe, causes a side effect, too
A void method can only be called for side effects. And the thing is: when you do static mocking, then that works on class level.
Meaning: you instruct PowerMock to "prevent" any of the static methods of some class from execution; you simply "erase" the side effects of all those static methods! So, by telling PowerMock to do those static mocks, all void methods are already "gone".
But as said, you might also call methods for their return value. And then is when the when() method of Mockito kicks in. You use that method to say: when that value-returning method is invoked, then do this or that.
Long story short; here is a [mcve] using the elements you asked for:
package ghostcat.test;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
class IgnoreCall {
public static void ignoreMethodCall(Object o) {
System.out.println("SHOULD NOT SHOW UP: " + o);
}
}
class CuT {
public static Object call(Object bean) {
System.out.println("statement1");
IgnoreCall.ignoreMethodCall(bean);
System.out.println("statement2");
return "whatever";
}
}
#RunWith(PowerMockRunner.class)
#PrepareForTest(IgnoreCall.class)
public class PMTest {
#Test
public void test() {
PowerMockito.mockStatic(IgnoreCall.class);
CuT.call("yeha");
}
}
As in your example ... there is IgnoreCall; used within that a static method that I just called "call".
This prints:
statement1
statement2
When I go in and comment out
// PowerMockito.mockStatic(IgnoreCall.class);
It prints:
statement1
SHOULD NOT SHOW UP: yeha
statement2
So, a simple example that should tell you exactly what you need to do.
I worked with eclipse neon, IBM java8 JDK, and simply imported all the JARs from powermock-mockito-junit-1.6.6.zip into my test project.
Suppose I have two sets of controllers in Spring:
/jsonapi1/*
/jsonapi2/*
both of which return objects that are to be interpretted as JSON text.
I'd like some kind of filter to wrap the responses from one set of these controllers so that:
the original response is contained within another object.
For example, if /jsonapi1/count returns:
{"num_humans":123, "num_androids":456}
then the response should be wrapped and returned as follows:
{ "status":0,
"content":{"num_humans":123, "num_androids":456}
}
if an exception happens in the controller, then filter should catch the exception and report it as follows
{ "status":5,
"content":"Something terrible happened"
}
The responses from the other controllers are returned unchanged.
We're currently customizing a MappingJackson2HttpMessageConverter passed to WebMvcConfigurerAdapter.configureMessageConverters in order to perform the above tasks. Works great except that it doesn't seem possible for this approach to be selective about the URLs (or controller classes) it applies to.
Is it possible to apply these kinds of wrappers to individual controller classes or URLs?
Update: Servlet filters look like a solution. Is it possible chose which filter gets applied to which controller methods, or which URLs?
I was struggling on this for multiple days. The solution by #Misha didn't work for me. I was able to finally get this working using ControllerAdvice and ResponseBodyAdvice.
ResponseBodyAdvice allows to inject custom transformation logic on the response returned by a controller but before it is converted to HttpResponse and committed.
This is how my controller method looks:
#RequestMapping("/global/hallOfFame")
public List<HallOfFame> getAllHallOfFame() {
return hallOfFameService.getAllHallOfFame();
}
Now i wanted to add some standard fields around the response like devmessage and usermessage. That logic goes into the ResponseAdvice:
#ControllerAdvice
public class TLResponseAdvice implements ResponseBodyAdvice<Object> {
#Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return true;
}
#Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
ServerHttpResponse response) {
// TODO Auto-generated method stub
final RestResponse<Object> output = new RestResponse<>();
output.setData(body);
output.setDevMessage("ResponseAdviceDevMessage");
output.setHttpcode(200);
output.setStatus("Success");
output.setUserMessage("ResponseAdviceUserMessage");
return output;
}
}
The entity classes look like this:
#Setter // All lombok annotations
#Getter
#ToString
public class RestResponse<T> {
private String status;
private int httpcode;
private String devMessage;
private String userMessage;
private T data;
}
#Entity
#Data // Lombok
public class HallOfFame {
#Id
private String id;
private String name;
}
To handle exceptions, simply create another ControllerAdvice with ExceptionHandler. Use the example in this link.
Advantages of this solution:
It keeps your controllers clean. You can support any return type from your controller methods.
Your controller return type class does not need to extend some base class as required by the AOP approach.
You do not need to hack your way through Spring filters by using HttpServletResponseWrappers. They come up with a performance penalty.
EDIT - 17th September 2019
To handle exceptions use #ExceptionHandler. Refer code below.
#ExceptionHandler(Exception.class)
#ResponseBody
public MyResponseEntity<Object> handleControllerException(HttpServletRequest request, Throwable ex) {
// default value
int httpCode = HttpStatus.INTERNAL_SERVER_ERROR.value();
if(ex instanceof ResourceNotFoundException) {
httpCode = HttpStatus.NOT_FOUND.value();
}
...
}
The way I understand your question, you have exactly three choices.
Option #1
Manually wrap your objects in simple SuccessResponse, ErrorResponse, SomethingSortOfWrongResponse, etc. objects that have the fields you require. At this point, you have per-request flexibility, changing the fields on one of the response wrappers is trivial, and the only true drawback is code repetition if many of the controller's request methods can and should be grouped together.
Option #2
As you mentioned, and filter could be designed to do the dirty work, but be wary that Spring filters will NOT give you access to request or response data. Here's an example of what it might look like:
#Component
public class ResponseWrappingFilter extends GenericFilterBean {
#Override
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain) {
// Perform the rest of the chain, populating the response.
chain.doFilter(request, response);
// No way to read the body from the response here. getBody() doesn't exist.
response.setBody(new ResponseWrapper(response.getStatus(), response.getBody());
}
}
If you find a way to set the body in that filter, then yes, you could easily wrap it up. Otherwise, this option is a dead end.
Option #3
A-ha. So you got this far. Code duplication is not an option, but you insist on wrapping responses from your controller methods. I'd like to introduce the true solution - aspect-oriented programming (AOP), which Spring supports fondly.
If you're not familiar with AOP, the premise is as follows: you define an expression that matches (like a regular expression matches) points in the code. These points are called join points, while the expressions that match them are called pointcuts. You can then opt to execute additional, arbitrary code, called advice, when any pointcut or combination of pointcuts are matched. An object that defines pointcuts and advice is called an aspect.
It's great for expressing yourself more fluently in Java. The only drawback is weaker static type checking. Without further ado, here's your response-wrapping in aspect-oriented programming:
#Aspect
#Component
public class ResponseWrappingAspect {
#Pointcut("within(#org.springframework.stereotype.Controller *)")
public void anyControllerPointcut() {}
#Pointcut("execution(* *(..))")
public void anyMethodPointcut() {}
#AfterReturning(
value = "anyControllerPointcut() && anyMethodPointcut()",
returning = "response")
public Object wrapResponse(Object response) {
// Do whatever logic needs to be done to wrap it correctly.
return new ResponseWrapper(response);
}
#AfterThrowing(
value = "anyControllerPointcut() && anyMethodPointcut()",
throwing = "cause")
public Object wrapException(Exception cause) {
// Do whatever logic needs to be done to wrap it correctly.
return new ErrorResponseWrapper(cause);
}
}
The final result will be the non-repeating response wrapping that you seek. If you only want some or one controller receive this effect, then update the pointcut to match methods only within instances of that controller (rather than any class holding the #Controller annotation).
You'll need to include some AOP dependencies, add the AOP-enabling annotation in a configuration class, and make sure something component-scans the package this class is in.
Simplest way i manage custom responses from controllers is by utilising the Map variable.
so your code ends up looking like:
public #ResponseBody Map controllerName(...) {
Map mapA = new HashMap();
mapA.put("status", "5");
mapA.put("content", "something went south");
return mapA;
}
beauty of is is that you can configure it any thousand ways.
Currently i use for object transmition, custom exception handling and data reporting, too easy.
Hope this helps
I am also using AOP with #Around. Developed a custom annotation and using that for point cut. I am using a global Response. It has the status, Message and data which is of type List of type
List <? extends parent> dataList
( which can solve your class cast exception). All the entities extends this Parent class. This way I can set all the data into my List.
Also I am using the message key as param with the custom annotation and setting it in action.
Hope this helps.