I have the following question regarding testing in Vue 2 with Jest.
Let's say I have a custom class
export class CustomDebouncer extends Debouncer{
public triggerUpdate(): void {
timeout(() => {
}, timeOut)
}
}
export class ClassA {
private _debouncer: CustomDebouncer;
}
How do I, in this case, replace the debouncer property in ClassA with a stub (and possibly als for all the rest of the classes that use the CustomDebouncer class in any way)?
export class CustomDebouncerStub {
triggerUpdate(): void {
console.log('stub update called')
}
}
I tried the explanation on https://jestjs.io/docs/es6-class-mocks but I can't seem to figure out how to work this out. I tried to mock with CustomDebouncer.prototype.triggerUpdate = jest.mock.fn() but I don't have access to this then.
Anybody got any pointers for me in this issue? Thanks!
Related
I have this code in a method I´m unittesting
public void SomeMethod()
{
IMyLogger log = new Logger();
log.ConfigLogger(); // Trying to not call this method
//...some other code...
}
Where this is the Logger class
public class Logger : IMyLogger
{
public void ConfigLogger()
{
//Serilog logging code I´m trying to not call in my unittests.
Log.Logger = new LoggerConfiguration()
.MinimumLevel.Debug()
.CreateLogger();
}
}
And this is the my unittest where I´m trying to mock away (not call the code inside of the ConfigLogger() method without luck.
public void Test()
{
var logger = A.Fake<IMyLogger>();
A.CallTo(() => logger.ConfigLogger()).DoesNothing(); //Not working..
}
So what I´m I missing here? Why do I think this should be just like this? Even though Serilog specialist give me a better way to unittest Serilog I would also like to find out how to "FakeItEasy a void method".
Your production code is still using a concrete instance of Logger. FakeItEasy cannot influence the behaviour of anything but FakeItEasy-created Fakes.
The pattern for use is:
create a Fake that your production code will use as a collaborator
configure the Fake
provide the Fake to an instance of the production class under test
execute the production code
optionally interrogate the Fake
As your production code is written now, there is no opportunity to inject a collaborator - it makes its own collaborator (log). In order to avoid calling Logger methods, you'll need to provide a way to inject an alternative IMyLogger.
You should avoid having to instantiate and configure your logger within the method.
Something like
public class SomeClass()
{
IMyLogger log;
public SomeClass(IMyLogger logger)
{
this.log = logger;
}
public void SomeMethod()
{
// code you want to test
}
}
Then just pass it into your class under test:
public void Test()
{
var logger = A.Fake<IMyLogger>();
var someClass = new SomeClass(logger);
// test someClass.SomeMethod()
}
I am a Dagger newbie.
TL;DR:
If an Android Service has any fields injected into it using Dagger, then in order to actually perform the injection, I need to have an instance of that Service.
In Robolectric tests, this corresponds to MyService service = Robolectric.buildService(MyService.class).get(). And then, objectGraph.inject(service);
However, rest of the code that actually starts MyService still uses context.startService(context, MyService.class);.
Question: What is the idiomatic way in Dagger to address this mismatch?
Let's say I have a Service as follows:
public class MyService {
#Inject Parser parser;
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
String data = intent.getStringExtra("data_to_be_parsed");
parser.parse(data);
}
}
Elsewhere in my code, I have an ApiClient class that does this:
public class ApiClient{
public static void parseInBackground(Context context, String data){
//This service does not have its fields injected
context.startService(new Intent(context, MyService.class).putExtra("data_to_be_parsed", data));
}
}
That parseInBackground method will be called from an Activity in response to user interaction.
Now, I'm following TDD and hence, I haven't yet written the Application Module for this. Here's the test module:
#Module(injects = MyService.class)
public class TestModule {
#Provides #Singleton Parser provideParser(){
return new MockParser();
}
}
And finally, the test case:
#RunWith(Robolectric.class)
public class ApiTest {
#Test
public void parseInBackground_ParsesCorrectly(){
//This service has its fields injected
MyService service = Robolectric.buildService(MyService.class).get();
ObjectGraph.create(new TestModule()).inject(service);
ApiClient.parseInBackground(Robolectric.application, "<user><name>droid</name></user>");
//Asserts here
}
}
As you can see, in the test, I retrieve an instance of the service and then inject the MockParser into it. However, the ApiClient class directly starts the service using an Intent. I don't have a chance to perform the injection.
I am aware that I can have MyService perform an injection on itself:
public void onCreate(){
ObjectGraph.create(new TestModule()).inject(this);
}
But then, I am hardcoding the TestModule here.
Is there an existing idiom in Dagger to set up dependencies for such situations?
It's the wrong way to hardcode your modules either in tests or in services. Better approach is to perform creation via your custom Application object which in turn will hold singleton ObjectGraph object. For example:
// in MyService class
#Override public void onCreate() {
super.onCreate();
MyApp.from(context).inject(this);
}
// in MyApp class
public static MyApp from(Context context) {
return (MyApp) context.getApplicationContext();
}
//...
private ObjectGraph objectGraph;
#Override public void onCreate() {
// Perform Injection
objectGraph = ObjectGraph.create(getModules());
objectGraph.inject(this);
}
public void inject(Object object) {
objectGraph.inject(object);
}
protected Object[] getModules() {
// return concrete modules based on build type or any other conditions.
}
Alternatively, you can refactor last method out into separate class and make different implementations for different flavors or build types. Also you may want to set overrides=true in your TestModule's annotation.
I am using PowerMock to mock static methods in junit tests, typically done as follows:
#RunWith(PowerMockRunner.class)
#PrepareForTest({Foo.class,Bar.class})
public class SomeUnitTest {
#Before
public void setUpTest() {
setUpFoo();
setUpBar();
}
private void setUpFoo() {
mockStatic(Foo.class);
when(Foo.someStaticMethod()).thenReturn(1);
}
private void setUpBar() {
mockStatic(Bar.class);
when(Bar.someStaticMethod()).thenReturn(2);
}
#Test
public void someTestCase() {
...
}
}
This works fine, but I'm finding that specifying the #PrepareForTest annotation is preventing me from making my testing API flexible.
What I'd like to do is something like the following:
public class MockLibraryOne {
public static void setUpLibraryOne() {
setUpFoo();
setUpBar();
}
private static void setUpFoo() {
mockStatic(Foo.class);
when(Foo.someStaticMethod()).thenReturn(1);
}
private static void setUpBar() {
mockStatic(Bar.class);
when(Bar.someStaticMethod()).thenReturn(2);
}
}
#RunWith(PowerMockRunner.class)
public class SomeUnitTest {
#Before
public void setUpTest() {
MockLibraryOne.setUpLibraryOne();
}
#Test
public void someTestCase() {
...
}
}
Here my unit test has a dependency on LibraryOne, but it does not know which classes LibraryOne depends on, so it does not know which classes to add to the #PrepareForTest annotation.
I could make SomeUnitTest extend MockLibraryOne and add the #PrepareForTest annotation to the MockLibraryOne class, but I will have dependencies on more than just MockLibraryOne in other unit tests, so inheritance is not a general solution.
Is there some way of programmatically preparing a class for testing under PowerMock, instead of using the #PrepareForTest annotation? For example, something like the following:
public class MockLibraryOne {
public static void setUpLibraryOne() {
setUpFoo();
setUpBar();
}
private static void setUpFoo() {
prepareForTest(Foo.class);
mockStatic(Foo.class);
when(Foo.someStaticMethod()).thenReturn(1);
}
private static void setUpBar() {
prepareForTest(Bar.class);
mockStatic(Bar.class);
when(Bar.someStaticMethod()).thenReturn(2);
}
}
I guess it would be nice if PowerMockRunner processed the #PrepareForTest annotation a little differently: for each specified class, it should not only add that class (and its hierarchy) to the list of classes to prepare for mocking, but then examine that class to see if it has any #PrepareForTest annotations as well:
#RunWith(PowerMockRunner.class)
#PrepareForTest({MockLibraryOne.class})
public class SomeUnitTest {
...
}
#PrepareForTest({Foo.class,Bar.class})
public class MockLibraryOne {
...
}
}
So in this the #PrepareForTest annotation on SomeUnitTest would find MockLibraryOne, and the #PrepareForTest annotation there would drag in Foo.class and Bar.class as well.
So perhaps writing my own test runner to replace PowerMockRunner may be a solution.
Or perhaps there's a simpler solution, using PowerMockAgent class, for example?
edit: Mock Policies may be one solution: https://code.google.com/p/powermock/wiki/MockPolicies
edit: Mock Policies works with PowerMockRunner but not (it seems) with PowerMockRule (which I sometimes require due to class loader issues).
What you try to achieve will not work.
The problem is that powermock must rewrite the client class's code to intercept the static invocation and it can't do this after the class is loaded. Thus it can only prepare a class for test before it is loaded.
Let's assume you want to mock the System.currentTimeMillis invocation in the following simple class.
class SystemClock {
public long getTime() {
return System.currentTimeMillis();
}
}
Powermock will not change the code of java.lang.System.currentTimeMillis, because it can't. Instead it changes the SystemClock's byte code so that it does not invoke System.currentTimeMillis anymore. Instead it invokes some other object that belong to powermock.
This is how powermock get's full control over the return value and allows you to write a test like this:
#RunWith(PowerMockRunner.class)
#PrepareForTest({ SystemClock.class })
public class PowerMockitoTest {
#Test
public void systemTimeMillis() {
SystemClock systemClock = new SystemClock();
PowerMockito.mockStatic(System.class);
PowerMockito.when(System.currentTimeMillis()).thenReturn(12345L);
long time = systemClock.getTime();
assertEquals(12345L, time);
}
}
You can see that powermock has rewritten the client class in the stacktrace of your debugger. Set a breakpoint at SystemClock.getTime and step into the invoked method.
As you can see SystemClock invokes a MockGateway.
If you take a look at the variables on the stack of the MockGateway invocation, you can see how the original System.currentTimeMillis method is handled.
Perhaps you're looking for a mock policy?
Could you help this (taken from documentation)?
You can also prepare whole packages for test by using wildcards:
#PrepareForTest(fullyQualifiedNames="com.mypackage.*")
So you can add the whole library to your prepare...
Why do you even want to mock static methods? Why not wrap those static methods in a class that you can mock with mockito?
class FooWraper {
void someMethod() {
Foo.someStaticMethod()
}
}
and then you can create a mock of your FooWraper. No need to use Powermock at all...
I'm following the accepted answer in this question but I'm getting a NullReferenceException.
What I need is having a partial mock stub a property (both getter and setter) to behave like a stub (as a simple automatic property). Currently I am able to stub the getter but not the setter.
Is this possible?
EDIT: this is a simple example, I hope it helps explaining my problem.
public class SomeClass
{
public virtual string SomeProperty
{
get{ return SomeMethodDependingOnDBOrAspSession(); }
set{ SomeMethodDependingOnDBOrAspSession(value); } // I want to avoid calling this setter implementation
}
}
var partialMock = MockRepository.GeneratePartialMock<SomeClass>();
partialMock.Stub(p => p.SomeProperty); // I want SomeProperty to behave as an automatic property
When using a PartialMock you can get auto-implemented property like behavior by using PropertyBehavior feature of Rhino Mocks. Given the class in your question, the following nunit test passes for me.
[Test]
public void TestPartialMock()
{
var someClass = MockRepository.GeneratePartialMock<SomeClass>();
someClass.Stub(x => x.SomeProperty).PropertyBehavior();
string val = "yo!";
Assert.DoesNotThrow(() => someClass.SomeProperty = val);
Assert.AreEqual(val, someClass.SomeProperty);
}
If you don't need a PartialMock you could use a Stub which has property behavior by default. You'd simply replace the first two lines of the test with:
var someClass = MockRepository.GenerateStub<SomeClass>();
im looking for something similar to what i would do with rhino mocks but in groovy.
i sometimes use partial mocks as well.
in ASP -- Rhino mocks
const string criteria = "somecriteriahere";
ISomeRepository mockSomeRepository = MockRepository.GenerateStrictMock<SomeRepository>();
mockSomeRepository.Expect(m => m.GetSomesByNumber(criteria)).Return(new List<Some>() { });
mockSomeRepository.Expect(m => m.GetSomesByName(criteria)).Return(new List<Some>() { });
mockSomeRepository.Expect(m => m.GetSomesByOtherName(criteria)).Return(new List<Some>() { });
mockSomeRepository.SearchForSomes(criteria);
mockSomeRepository.VerifyAllExpectations();
--------note the virtual -------
public class SomeRepository : ISomeRepository {
public virtual IEnumerable<Some> GetSomesByNumber(string num)
{
//some code here
}
public virtual IEnumerable<Some> GetSomesByName(string name)
{
//some code here
}
public virtual IEnumerable<Some> GetSomesByOtherName(string name)
{
//some code here
}
public IEnumerable<Some> SearchForSomes(string criteria) {
this.GetSomesByNumber(criteria); //tested fully seperatly
this.GetSomesByName(criteria); //tested fully seperatly
this.GetSomesByOtherName(criteria); //tested fully seperatly
//other code to be tested
}
}
GetSomesByNumber, GetSomesByName, GetSomesByOtherName would be tested fully seperatly. If i actually provided values and went into those functions, to me, that seems like in integration test where im testing multiple functionalities and not one unit of work.
So, SearchForSomes i would only be testing that method and mocking away all other dependencies.
In Grails
class XService {
def A() {
}
def B() {
def result = this.A()
//do some other magic with result
}
}
I have tried this -- but failed
def XServiceControl = mockFor(XService)
XServiceControl.demand.A(1..1) { -> return "aaa" }
// Initialise the service and test the target method.
//def service = XServiceControl.createMock();
//def service = XServiceControl.proxyInstance()
// Act
//def result = XServiceControl.B(_params);
XServiceControl.use {
new XService().B(_params)
}
Ive got no idea how to do this, does any one know how?
Thanks
If you're using groovy MockFor (e.g. groovy.mock.interceptor.MockFor), then you need to enclode the usage in a .use{} block.
However, it looks like you are calling mockFor from within a grails.test.GrailsUnitTestCase. In that case, there's no need for the .use{} block: the scope of the mock is the whole test.
thanks for your reply ataylor
seem what i was trying to accomplish is something called partial/half mocking. Here are some links.
http://www.gitshah.com/2010/05/how-to-partially-mock-class-and-its.html
http://mbrainspace.blogspot.com/2010/02/partial-half-mocks-why-theyre-good-real.html
https://issues.apache.org/jira/browse/GROOVY-2630
https://issues.apache.org/jira/browse/GROOVY-1823
http://java.dzone.com/articles/new-groovy-171-constructor
I didnt accomplish this, i ended up extracting B() into its own class and injecting a mock of XService into B's class -- Dependency Injection. I was also informed that extracting away dependencies is a better practice for testing. So, i am now very carefull when using this.() :D