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
}
I'm using Mockito 1.9.0. I want mock the behaviour for a single method of a class in a JUnit test, so I have
final MyClass myClassSpy = Mockito.spy(myInstance);
Mockito.when(myClassSpy.method1()).thenReturn(myResults);
The problem is, in the second line, myClassSpy.method1() is actually getting called, resulting in an exception. The only reason I'm using mocks is so that later, whenever myClassSpy.method1() is called, the real method won't be called and the myResults object will be returned.
MyClass is an interface and myInstance is an implementation of that, if that matters.
What do I need to do to correct this spying behaviour?
Let me quote the official documentation:
Important gotcha on spying real objects!
Sometimes it's impossible to use when(Object) for stubbing spies. Example:
List list = new LinkedList();
List spy = spy(list);
// Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
when(spy.get(0)).thenReturn("foo");
// You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);
In your case it goes something like:
doReturn(resultsIWant).when(myClassSpy).method1();
In my case, using Mockito 2.0, I had to change all the any() parameters to nullable() in order to stub the real call.
My case was different from the accepted answer. I was trying to mock a package-private method for an instance that did not live in that package
package common;
public class Animal {
void packageProtected();
}
package instances;
class Dog extends Animal { }
and the test classes
package common;
public abstract class AnimalTest<T extends Animal> {
#Before
setup(){
doNothing().when(getInstance()).packageProtected();
}
abstract T getInstance();
}
package instances;
class DogTest extends AnimalTest<Dog> {
Dog getInstance(){
return spy(new Dog());
}
#Test
public void myTest(){}
}
The compilation is correct, but when it tries to setup the test, it invokes the real method instead.
Declaring the method protected or public fixes the issue, tho it's not a clean solution.
The answer by Tomasz Nurkiewicz appears not to tell the whole story!
NB Mockito version: 1.10.19.
I am very much a Mockito newb, so can't explain the following behaviour: if there's an expert out there who can improve this answer, please feel free.
The method in question here, getContentStringValue, is NOT final and NOT static.
This line does call the original method getContentStringValue:
doReturn( "dummy" ).when( im ).getContentStringValue( anyInt(), isA( ScoreDoc.class ));
This line does not call the original method getContentStringValue:
doReturn( "dummy" ).when( im ).getContentStringValue( anyInt(), any( ScoreDoc.class ));
For reasons which I can't answer, using isA() causes the intended (?) "do not call method" behaviour of doReturn to fail.
Let's look at the method signatures involved here: they are both static methods of Matchers. Both are said by the Javadoc to return null, which is a little difficult to get your head around in itself. Presumably the Class object passed as the parameter is examined but the result either never calculated or discarded. Given that null can stand for any class and that you are hoping for the mocked method not to be called, couldn't the signatures of isA( ... ) and any( ... ) just return null rather than a generic parameter* <T>?
Anyway:
public static <T> T isA(java.lang.Class<T> clazz)
public static <T> T any(java.lang.Class<T> clazz)
The API documentation does not give any clue about this. It also seems to say the need for such "do not call method" behaviour is "very rare". Personally I use this technique all the time: typically I find that mocking involves a few lines which "set the scene" ... followed by calling a method which then "plays out" the scene in the mock context which you have staged... and while you are setting up the scenery and the props the last thing you want is for the actors to enter stage left and start acting their hearts out...
But this is way beyond my pay grade... I invite explanations from any passing Mockito high priests...
* is "generic parameter" the right term?
One more possible scenario which may causing issues with spies is when you're testing spring beans (with spring test framework) or some other framework that is proxing your objects during test.
Example
#Autowired
private MonitoringDocumentsRepository repository
void test(){
repository = Mockito.spy(repository)
Mockito.doReturn(docs1, docs2)
.when(repository).findMonitoringDocuments(Mockito.nullable(MonitoringDocumentSearchRequest.class));
}
In above code both Spring and Mockito will try to proxy your MonitoringDocumentsRepository object, but Spring will be first, which will cause real call of findMonitoringDocuments method. If we debug our code just after putting a spy on repository object it will look like this inside debugger:
repository = MonitoringDocumentsRepository$$EnhancerBySpringCGLIB$$MockitoMock$
#SpyBean to the rescue
If instead #Autowired annotation we use #SpyBean annotation, we will solve above problem, the SpyBean annotation will also inject repository object but it will be firstly proxied by Mockito and will look like this inside debugger
repository = MonitoringDocumentsRepository$$MockitoMock$$EnhancerBySpringCGLIB$
and here is the code:
#SpyBean
private MonitoringDocumentsRepository repository
void test(){
Mockito.doReturn(docs1, docs2)
.when(repository).findMonitoringDocuments(Mockito.nullable(MonitoringDocumentSearchRequest.class));
}
Important gotcha on spying real objects
When stubbing a method using spies , please use doReturn() family of methods.
when(Object) would result in calling the actual method that can throw exceptions.
List spy = spy(new LinkedList());
//Incorrect , spy.get() will throw IndexOutOfBoundsException
when(spy.get(0)).thenReturn("foo");
//You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);
I've found yet another reason for spy to call the original method.
Someone had the idea to mock a final class, and found about MockMaker:
As this works differently to our current mechanism and this one has different limitations and as we want to gather experience and user feedback, this feature had to be explicitly activated to be available ; it can be done via the mockito extension mechanism by creating the file src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker containing a single line: mock-maker-inline
Source: https://github.com/mockito/mockito/wiki/What%27s-new-in-Mockito-2#mock-the-unmockable-opt-in-mocking-of-final-classesmethods
After I merged and brought that file to my machine, my tests failed.
I just had to remove the line (or the file), and spy() worked.
One way to make sure a method from a class is not called is to override the method with a dummy.
WebFormCreatorActivity activity = spy(new WebFormCreatorActivity(clientFactory) {//spy(new WebFormCreatorActivity(clientFactory));
#Override
public void select(TreeItem i) {
log.debug("SELECT");
};
});
As mentioned in some of the comments, my method was "static" (though being called on by an instance of the class)
public class A {
static void myMethod() {...}
}
A instance = spy(new A());
verify(instance).myMethod(); // still calls the original method because it's static
Work around was make an instance method or upgrade Mockito to a newer version with some config: https://stackoverflow.com/a/62860455/32453
Bit late to the party but above solutions did not work for me , so sharing my 0.02$
Mokcito version: 1.10.19
MyClass.java
private int handleAction(List<String> argList, String action)
Test.java
MyClass spy = PowerMockito.spy(new MyClass());
Following did NOT work for me (actual method was being called):
1.
doReturn(0).when(spy , "handleAction", ListUtils.EMPTY_LIST, new String());
2.
doReturn(0).when(spy , "handleAction", any(), anyString());
3.
doReturn(0).when(spy , "handleAction", null, null);
Following WORKED:
doReturn(0).when(spy , "handleAction", any(List.class), anyString());
I have written a custom JUnit runner that I want to become part of an eclipse plugin that will launch tests using this runner without having to apply the #RunWith annotation to the class. I have managed to get an additional item under the 'Run As' context menu, using the org.eclipse.debug.ui.launchShortcuts extension point. However, I am not sure how to invoke the test using my custom runner.
So I figured out a way to do what I wanted. However, it does seem a bit hacky. But, I thought that I would post the answer here in case someone else runs into the same problem.
First you have to register a junit kind like this:
<extension point="org.eclipse.jdt.junit.internal_testKinds">
<kind
id="my.junit.kind"
displayName="Your Kind Name"
finderClass="org.eclipse.jdt.internal.junit.launcher.JUnit4TestFinder"
loaderPluginId="org.eclipse.jdt.junit4.runtime"
loaderClass="your.test.loader.MyLoaderClass">
<runtimeClasspathEntry pluginId="org.eclipse.jdt.junit4.runtime" />
<runtimeClasspathEntry pluginId="org.eclipse.jdt.junit.core" />
<runtimeClasspathEntry pluginId="org.eclipse.jdt.junit.runtime"/>
</kind>
</extension>
In the xml you have to specify a custom implementation of org.eclipse.jdt.internal.junit.runner.ITestLoaderwhich in turn returns an implementation of org.eclipse.jdt.internal.junit.runner.ITestReference. The core part is the implementation of ITestReference, because this is where you create an instance of your custom JUnit runner.
public class MyTestReference extends JUnit4TestReference
{
public MyTestReference(final Class<?> p_clazz, String[] p_failureNames)
{
super(new Request()
{
#Override
public Runner getRunner()
{
return new MyCustomRunner(p_clazz);
}
}, p_failureNames);
}
...
}
Then finally you have to link this with a launch shortcut that sets the kind appropriately
public class MyJunitLaunchShortcut extends JUnitLaunchShortcut
{
#Override
protected ILaunchConfigurationWorkingCopy createLaunchConfiguration(IJavaElement p_element) throws CoreException
{
ILaunchConfigurationWorkingCopy config = super.createLaunchConfiguration(p_element);
config.setAttribute(JUnitLaunchConfigurationConstants.ATTR_TEST_RUNNER_KIND, "my.junit.kind");
return config;
}
}
This does use a bunch of internal classes, so there is probably a better way. But this seems to work.
I am new to Windsor and am trying to implement the most basic constructor injection. Apparently the API has changed so much over the recent versions that the documentation that is for the current version seems to assume you already know how to do it, and the documentation for the old versions is outdated.
I have a simple test component:
public class ConstructorInjectedComponent
{
public IMyComponent Component { get; set; }
public ConstructorInjectedComponent(IMyComponent component)
{
Component = component;
}
}
There is a simple implementation of IMyComponent:
public class AMyComponent : IMyComponent
{
public string Name { get; set; }
public AMyComponent()
{
Name = Guid.NewGuid().ToString("N");
}
}
And I want to somehow register my types with Windsor such that I can get back an instance of ConstructorInjectedComponent that contains an instance of its dependency: IMyComponent.
I've register AMyComponent like so:
_container.Register(Component.For(typeof(AMyComponent)));
I've register ConstructorInjectedComponent like this:
_container.Register(Component.For(typeof(ConstructorInjectedComponent)));
and tried to resolve it with
_container.Resolve(typeof(ConstructorInjectedComponent));
But that fails with "can't create component ConstructorInjectedComponent because it has dependencies which need to be satisfied.
so I try to pass in an IDictionary of dependencies for the ConstructorInjectedComponent ... and this is where the documentation fails me.
I have no idea how to define that dictionary. I can find no documentation which explains it. I've tried this:
var d = new Dictionary<string, string>() {{"IMyComponent", "AMyComponent"}};
_container.Register(Component.For(typeof(ConstructorInjectedComponent))
.DependsOn(dependencies));
But that fails with the same "has dependencies that need to be resolved" error.
What am I doing wrong?
First it's crucial to make sure you understand the basic concepts, namely what a component is, what a service is, and what a dependency is.
The documentation about it is quite good.
The documentation about how to use registration API should help you get going.
The tl;dr asnwer is: since ConstructorInjectedComponent depends on IMyComponent make sure you register AMyComponent to expose IMyComponent as a service.
_container.Register(Component.For<IMyComponent>().ImplementedBy<AMyComponent>());
Hi I am new to unit testing. Is it possible to access methods that are private?
A very simple example
ObjectA
----------
File file;
private void setupFile (){
//do something
file = "C:\file.dat"
}
In TestCase
File sth = ObjectA.setupFile();
assertNotNull(sth);
I am unable to test whether the file variable is null in method ObjectA.setup()
as I cannot run ObjectA.setupFile()
I am not sure about whether doing like this make sense in terms of unit testing.
So is that a better practice to write every method returning sth and set them public for easier unit testing?
Thanks in advance
In general, you should avoid changing the access of a method/field to enable testing. If you do this then you risk developers using the method directly.
However, if you do need to, then making it protected as Deco says is a good way, so it's accessible from the JUnit tests. If you do this, make sure that it is well documented that this is an method for internal use.
A better way is to test the behaviour of the public methods; you shouldn't care about internal implementation details of a class, so you should only be testing public methods. It's hard to tell from your code, but presumably, the setupFile() has effects later on other methods, so you can test those effects, not the fact that file is not null.
External dependencies (such as dependencies on file system, environment variables) can be worked around in your tests, or injected directly into the class. For the general principle, see my answer to How to test code dependent on environment variables using JUnit?
If it is not absolutely necessary to have the method as private, you can have it as package private (i.e. default access) so that you can call it directly in a JUnit test.
Package private methods can only be used in the package that they are declared, and do not become part of the API of the class. You declare a method package private by putting no modifier on it's declaration.
Here's an example to demonstrate:
public class MyClass() {
int foo;
public MyClass() {
this.foo = 0;
}
void notSoComplexCalculationMethod(int a) {
foo = a * 2;
}
//Other methods here . . .
}
public class MyClassTest extends TestCase {
private MyClass myClass;
protected void setUp() {
super.setUp();
myClass = new MyClass();
}
public void testNotSoComplexCalculationMethod() {
int a = 2;
assertEquals(4, myClass.notSoComplexCalculationMethod(a));
//Unit test passes, yay! Now you've tested a package private method.
}
}