Unable to get default constructor for Integration class ninject - c#-4.0

I'm new on using ninject and Dependency Injection, and have a problem using it.
I try to using Ninject on my class libray, and building an integration tests.
now, I see in many example that, for using ninject is just specified the DI Module like this:
Public Class DIModule : NinjectModule
public override void Load()
{
Bind<IUSAServices>().To<USAServices>();
}
And then on my test class, I try to call my dependency is like this:
[TestClass]
public class USAIntegrationTests
{
private readonly IUSAServices _usaService;
public USAIntegrationTests(IUSAServices usaServices)
{
_usaService = usaServices;
}
[TestMethod]
public void ValidateUserTests()
{
Assert.IsTrue(_usaService.ValidateUser("username1", "password1"));
}
}
And Getting this error:
Unable to get default constructor for class USATests.IntegrationTests.USAIntegrationTests.
However I read the documentation and tried like this:
[TestClass]
public class USAIntegrationTests
{
private readonly IUSAServices _usaService;
public USAIntegrationTests()
{
using (IKernel kernel = new StandardKernel(new DIModule()))
{
_usaService = kernel.Get<IUSAServices>();
}
}
[TestMethod]
public void ValidateUserTests()
{
Assert.IsTrue(_usaService.ValidateUser("mantab", "banget"));
}
}
The test is works properly.
My question is, why I getting that error? is that some way to get around it?
Thanks in advance.

Unit test frameworks require your test classes to have a default constructor. You usually can't integrate DI containers with them. Instead of using constructor injection, you will have to call the container directly from your code, although for unit tests you should typically not have a container at all (for integration tests however, this is okay).

You can add a paramterless constructor for the class. It worked for me.

Related

How can I run code in JUnit before Spring starts?

How can I run code in my #RunWith(SpringRunner.class) #SpringBootTest(classes = {...}) JUnit test before Spring starts?
This question has been asked several times (e.g. 1, 2) but was always "solved" by some configuration recommendation or other, never with a universal answer. Kindly don't question what I am about to do in that code but simply suggest a clean way to do it.
Tried so far and failed:
Extend SpringJUnit4ClassRunner to get a class whose constructor can run custom code before initializing Spring. Failed because super(testClass) must be called first thing and already does a whole lot of things that get in the way.
Extend Runner to get a class that delegates to SpringRunner instead of inheriting it. This class could run custom code in its constructor before actually instantiating the SpringRunner. However, this setup fails with obscure error messages like java.lang.NoClassDefFoundError: javax/servlet/SessionCookieConfig. "Obscure" because my test has no web config and thus shouldn't meddle with sessions and cookies.
Adding an ApplicationContextInitializer that is triggered before Spring loads its context. These things are easy to add to the actual #SpringApplication, but hard to add in Junit. They are also quite late in the process, and a lot of Spring has already started.
One way to do it is to leave out SpringRunner and use the equivalent combination of SpringClassRule and SpringMethodRule instead. Then you can wrap the SpringClassRule and do your stuff before it kicks in:
public class SomeSpringTest {
#ClassRule
public static final TestRule TestRule = new TestRule() {
private final SpringClassRule springClassRule =
new SpringClassRule();
#Override
public Statement apply(Statement statement, Description description) {
System.out.println("Before everything Spring does");
return springClassRule.apply(statement, description);
}
};
#Rule
public final SpringMethodRule springMethodRule = new SpringMethodRule();
#Test
public void test() {
// ...
}
}
(Tested with 5.1.4.RELEASE Spring verison)
I don't think you can get more "before" than that. As for other options you could also check out #BootstrapWith and #TestExecutionListeners annotations.
Complementing jannis' comment on the question, the option to create an alternative JUnit runner and let it delegate to the SpringRunner does work:
public class AlternativeSpringRunner extends Runner {
private SpringRunner springRunner;
public AlternativeSpringRunner(Class testClass) {
doSomethingBeforeSpringStarts();
springRunner = new SpringRunner(testClass);
}
private doSomethingBeforeSpringStarts() {
// whatever
}
public Description getDescription() {
return springRunner.getDescription();
}
public void run(RunNotifier notifier) {
springRunner.run(notifier);
}
}
Being based on spring-test 4.3.9.RELEASE, I had to override spring-core and spring-tx, plus javax.servlet's servlet-api with higher versions to make this work.

How to setup ServiceStack xUnit tests for a few services at once?

how do you guys test a few services at once using ServiceStack and xUnit?
I have TestSetup that works all right and I inherit it by test classes like this:
public class TestSetup : IDisposable
{
protected ServiceStackHost appHost;
public TestSetup()
{
appHost = new BasicAppHost().Init();
var container = appHost.Container;
//code
}
}
then example test class constructor:
public exampleServiceTest() : base()
{
var container = appHost.Container;
//RegisterAutoWired code
}
And this works fine if I test one class at once, then another and so on. But if I want to run all tests, I get appHost instance already exists which is obvious. How should I solve this problem to be able to run all tests at once?
SOLUTION:
The solution is to create empty class that implements ICollectionFixture and decorate it with CollectionDefinition("Name"). Then you only have to decorate your test class with Collection("Name") and properly set test classes constructors (resolve services, create var container for that etc.). Pretty simple and clean solution on xUnit, everything works fine now. Thanks for the help again.
You can't run multiple tests with AppHost's concurrently within the same AppDomain. The appHost instance your test uses needs to be disposed before the next integration test is run.
See ServiceStack's Integration Tests example for how it uses NUnit's [OneTimeTearDown] to dispose of the AppHost after the test fixture is run:
public class CustomerRestExample
{
const string BaseUri = "http://localhost:2000/";
ServiceStackHost appHost;
public CustomerRestExample()
{
//Start your AppHost on TestFixtureSetUp
appHost = new AppHost()
.Init()
.Start(BaseUri);
}
[OneTimeTearDown]
public void OneTimeTearDown() => appHost.Dispose();
}

JukitoRunner, bind mock of final class

How to bind mock of final class in Jukito ?
For example :
public final class SomeFinalClass(){
public SomeFinalClass(String someString){
}
}
//Testing class
#Runwith(JukitoRunner.class)
public class TestingClass(){
#Inject
private SomeFinalClass someFinalClassMock;
public static class TestModule extends JukitoModule {
#Override
protected void configureTest() {
// bind(SomeClient.class).in(TestSingleton.class);
}
#Provides
public SomeFinalClass getSomkeFinalClass() {
return Mokito.mock(SomeFinalClass.class); //throws error
}
}
}
Is there a way i can use PowerMockito with JukitoRunner ?
You can mock a final class if you're using Mockito 2. From Mockito 2 Wiki:
Mocking of final classes and methods is an incubating, opt-in feature. It uses a combination of Java agent instrumentation and subclassing in order to enable mockability of these types. 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.
After you created this file, Mockito will automatically use this new engine and one can do :
final class FinalClass {
final String finalMethod() { return "something"; }
}
FinalClass concrete = new FinalClass();
FinalClass mock = mock(FinalClass.class);
given(mock.finalMethod()).willReturn("not anymore");
assertThat(mock.finalMethod()).isNotEqualTo(concrete.finalMethod());

Is it possible to call default implementations of interfaces with Mockito's doCallRealMethod?

Suppose I have the following interface:
public interface ISomething {
default int doStuff() {
return 2 * getValue();
}
int getValue();
}
When I now mock this interface like this:
#Mock
private ISomething _something;
#Before
public void setup() {
doCallRealMethod().when(_something).doStuff();
}
and try to test the doStuff() method like the following:
#Test
public void testDoStuff() {
when(_something.getValue()).thenReturn(42);
assertThat("doStuff() returns 84", _something.doStuff(), is(84));
}
I expect the test to succeed, but I get:
org.mockito.exceptions.base.MockitoException:
Cannot call real method on java interface. Interface does not have any implementation!
Calling real methods is only possible when mocking concrete classes.
I tried subclassing ISomething with an abstract class like this:
public abstract class Something implements ISomething {
}
and mock this class like above. With this approach, I get the same.
Does Mockito not support calling default implementations?
That's correct. The current version of Mockito doesn't support this. You could raise a feature request here. Do note that it seems to be related to issue 456 which was fixed in release 1.10.0, so please make sure you test this in the latest version first.
I was working on a project using Mockito 1.9.5 and ran into the same issue that you found. We couldn't upgrade Mockito because of the way our build server worked. The problem we ran into was when we were writing unit tests for the concrete subclasses, as we couldn't stub out or include the default methods from the interface in our mock objects (so slightly different from your example).
Here is an example subclass using your model:
public class ConcreteSomething implements ISomething {
#Override
int getValue()
{
return 42;
}
}
Then in the unit test class, we explicitly made a private inner class. This class overrode all the default methods of the concrete class under test (i.e. ConcreteSomething) with the interface's default implementation. So in this example, something like:
private class ConcreteSomethingDefaultImpl extends ConcreteSomething {
#Override
int doStuff() {
return super.doStuff();
}
}
For us, a mock made using mock(ConcreteSomething.class) couldn't have it's default methods called using doCallRealMethod(), but mock(ConcreteSomethingDefaultImpl.class) could, and more importantly, it was the default implementation code in the interface that was being used.
I hope that helps anyone else who is constrained to use a particular version of Mockito.

Invalid signature for SetUp or TearDown method - What am I doing wrong?

I am trying to do some dependency injection for my tests using nUnit. I'm new to TDD and nUnit so it's possible I am missing something simple. So basically I've created a SetUp method for my interfaces. I originally was using a constructor but I read it's bad to do this when doing TDD so I now using a method.
When I run my test I construct an object and assign it to the interface and then I call a method using that interface. I want to test if it can parse a string decimal.
When I run my test it says test failed and the message is:Invalid signature for SetUp or TearDown method
See below for the actual code:
public class DonorTests
{
private IDonor _Donor;
private IValidateInput _ValidInput;
//DonorTests(IDonor donor, IValidateInput validInput)
//{
// _Donor = donor;
// _ValidInput = validInput;
//}
[SetUp]
void Setup(IDonor donor, IValidateInput validInput)
{
_Donor = donor;
_ValidInput = validInput;
}
[Test]
public void HandleStringNotDecimal()
{
_ValidInput = new ValidateInput();
Assert.IsTrue(_ValidInput.IsDecimal("3445.3450"));
}
}
My class that uses this interface
public class ValidateInput : IValidateInput
{
public decimal RoundTwoDecimalPlaces(decimal amount)
{
return Math.Round(amount);
}
public bool IsDecimal(string amount)
{
decimal ParsedDecimal;
return Decimal.TryParse(amount, out ParsedDecimal);
}
public decimal ConvertToString(string value)
{
decimal ParsedDecimal;
Decimal.TryParse(value, out ParsedDecimal);
return ParsedDecimal;
}
}
You're injecting dependencies using constructor injection previously, right? I think you will not be able to perform dependency injection using method decorated with SetUpAttribute because such method has to be parameterless. Also Setup method has to be public, see this SO thread.
How are we typically dealing with similar situations in our company is:
[TestFixture]
public class DonorTests
{
private IDonor _Donor;
private IValidateInput _ValidInput;
[SetUp]
public void Setup()
{
_Donor = new Donor();
_ValidInput = new ValidateInput();
}
[Test]
public void HandleStringNotDecimal()
{
Assert.IsTrue(_ValidInput.IsDecimal("3445.3450"));
}
}
Or if construction of ValidInput and Donor is cheap then we simply create new instance for each test, having special method for that purpose so when we decide to test another implementation of IValidateInput then it is enough to change it in one place only:
[TestFixture]
public class DonorTests
{
[Test]
public void HandleStringNotDecimal()
{
var validInput = CreateValidateInput();
Assert.IsTrue(validInput .IsDecimal("3445.3450"));
}
private static IValidateInput CreateValidateInput()
{
return new ValidateInput();
}
}
Besides the cause mentioned in the accepted answer, I have met the same error when leaving method as non-public (private or protected).
NUnit most probably relies on reflection and does not deal with non-public methods, so special methods (i.e. decorated with NUnit specific attributes) must be public.

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