While reading one of the articles for Data Driven Testing, I came across a term 'parametrization of a test'. Could someone explain to me what is meant by parameterization here?
Let's see an example with TestNG. Suppose you have function SomeClass.calculate(int value). You want to check the results the function returns on different input values.
With not-parametrized tests you do something like this:
#Test
public void testCalculate1()
{
assertEquals(SomeClass.calculate(VALUE1), RESULT1)
}
#Test
public void testCalculate2()
{
assertEquals(SomeClass.calculate(VALUE2), RESULT2)
}
With parametrized test:
//This test method declares that its data should be supplied by the Data Provider
//named "calculateDataProvider"
#Test(dataProvider = "calculateDataProvider")
public void testCalculate(int value, int result)
{
assertEquals(SomeClass.calculate(value), result)
}
//This method will provide data to any test method that declares that its Data Provider
//is named "calculateDataProvider"
#DataProvider(name = "calculateDataProvider")
public Object[][] createData()
{
return new Object[][] {
{ VALUE1, RESULT1 },
{ VALUE2, RESULT2 },
};
}
This way, TestNG engine will generate two tests from testCalculate method, providing parameters from array, returned by createData function.
For more details see documentation.
Related
I am trying to learn TypeScript, and need some advice on implementing generic collection types. I put the dictionary and HashSet in another question, here I'd like any advice on my list type.
Especially the ForEach-Operation looks a bit strange. I think I found it in another question here, and "improved" by returning true or false to give feedback if the iteration was stopped early or completed.
import { IForEachFunction } from "./IForEachFunction"
export class List<T> {
private _items: Array<T>;
public constructor() {
this._items = [];
}
public get Count(): number {
return this._items.length;
}
public Item(index: number): T {
return this._items[index];
}
public Add(value: T): void {
this._items.push(value);
}
public RemoveAt(index: number): void {
this._items.splice(index, 1);
}
public Remove(value: T): void {
let index = this._items.indexOf(value);
this.RemoveAt(index);
}
public ForEach(callback: IForEachFunction<T>): boolean {
for (const element of this._items) {
if (callback(element) === false) {
return false;
}
}
return true;
}
}
The ForEach-Iteration relies on an interface from another file:
export interface IForEachFunction<T> {
(callback: T): boolean | void;
}
You would use my list and the ForEach-Method like this:
let myList: List<a_type> = new List<a_type>();
let completed: boolean = myList.ForEach(xyz => {
// do something with xyz
return false; // aborts the iteration
return true; // continues with the next element
});
if (completed) // we can see what happened "during" the iteration
I think this is not bad, but I'd appreciate any input. I am not sure if I use the === correctly.
Another question which I really like to know: How could I define a function with the interface IForEachFunction? I do not really "re-use" that interface visibly, I always declare an anonymous method as shown above. If I wanted to call a method having the interface definition, is that possible?
Thanks!
Ralf
One problem I see is that you have an interface instance:
callback: IForEachFunction<T>
This contains a method called
callback()
But you only call callback once. You would have call callback() method inside your interface:
callback.callback()
Also your code looks like it is inspired by C# or Java. In TypeScript you would often just use an array. This simplifies certain code constructs.
I am working on a unit test of an instance method. The method happens to be an ASP.NET MVC 4 controller action, but I don't think that really matters much. We just found a bug in this method, and I'd like to use TDD to fix the bug and make sure it doesn't come back.
The method under test calls a service which returns an object. It then calls an internal method passing a string property of this object. The bug is that under some circumstances, the service returns null, causing the method under test to throw a NullReferenceException.
The controller uses dependency injection, so I have been able to mock the service client to have it return a null object. The problem is that I want to change the method under test so that when the service returns null, the internal method should be called with a default string value.
The only way I could think to do this is to use a mock for the class under test. I want to be able to assert, or Verify that this internal method has been called with the correct default value. When I try this, I get a MockException stating that the invocation was not performed on the mock. Yet I was able to debug the code and see the internal method being called, with the correct parameters.
What's the right way to prove that the method under test calls another method passing a particular parameter value?
I think there's a code smell here. The first question I'll ask myself in such a situation is, is the "internal" method really internal/ private to the controller under test. Is it the controller's responsibility to do the "internal" task? Should the controller change when the internal method's implementation changes? May be not.
In that case, I would pull out a new targeted class, which has a public method which does the stuff which was until now internal to the controller.
With this refactoring in place, I would use the callback mechanism of MOQ and assert the argument value.
So eventually, you will end up mocking two dependancies:
1. The external service
2. The new targeted class which has the controller's internal implementation
Now your controller is completely isolated and can be unit tested independently. Also, the "internal" implementation becomes unit testable and should have its own set of unit tests too.
So your code and test would look something like this:
public class ControllerUnderTest
{
private IExternalService Service { get; set; }
private NewFocusedClass NewFocusedClass { get; set; }
const string DefaultValue = "DefaultValue";
public ControllerUnderTest(IExternalService service, NewFocusedClass newFocusedClass)
{
Service = service;
NewFocusedClass = newFocusedClass;
}
public void MethodUnderTest()
{
var returnedValue = Service.ExternalMethod();
string valueToBePassed;
if (returnedValue == null)
{
valueToBePassed = DefaultValue;
}
else
{
valueToBePassed = returnedValue.StringProperty;
}
NewFocusedClass.FocusedBehvaior(valueToBePassed);
}
}
public interface IExternalService
{
ReturnClass ExternalMethod();
}
public class NewFocusedClass
{
public virtual void FocusedBehvaior(string param)
{
}
}
public class ReturnClass
{
public string StringProperty { get; set; }
}
[TestClass]
public class ControllerTests
{
[TestMethod]
public void TestMethod()
{
//Given
var mockService = new Mock<IExternalService>();
mockService.Setup(s => s.ExternalMethod()).Returns((ReturnClass)null);
var mockFocusedClass = new Mock<NewFocusedClass>();
var actualParam = string.Empty;
mockFocusedClass.Setup(x => x.FocusedBehvaior(It.IsAny<string>())).Callback<string>(param => actualParam = param);
//when
var controller = new ControllerUnderTest(mockService.Object, mockFocusedClass.Object);
controller.MethodUnderTest();
//then
Assert.AreEqual("DefaultValue", actualParam);
}
}
Edit: Based on the suggestion in the comments to use "verify" instead of callback.
Easier way to verify the parameter value is by using strict MOQ behavior and a verify call on the mock after system under test is executed.
Modified test could look like below:
[TestMethod]
public void TestMethod()
{
//Given
var mockService = new Mock<IExternalService>();
mockService.Setup(s => s.ExternalMethod()).Returns((ReturnClass)null);
var mockFocusedClass = new Mock<NewFocusedClass>(MockBehavior.Strict);
mockFocusedClass.Setup(x => x.FocusedBehvaior(It.Is<string>(s => s == "DefaultValue")));
//When
var controller = new ControllerUnderTest(mockService.Object, mockFocusedClass.Object);
controller.MethodUnderTest();
//Then
mockFocusedClass.Verify();
}
"The only way I could think to do this is to use a mock for the class under test."
I think you should not mock class under test. Mock only external dependencies your class under test has. What you could do is to create a testable-class. It would be a class which derives from your CUT and here you can catch the calls to the another method and verify it's parameter later. HTH
Testable class in the example is named MyTestableController
Another method is named InternalMethod.
Short example:
[TestClass]
public class Tests
{
[TestMethod]
public void MethodUnderTest_WhenServiceReturnsNull_CallsInternalMethodWithDefault()
{
// Arrange
Mock<IService> serviceStub = new Mock<IService>();
serviceStub.Setup(s => s.ServiceCall()).Returns((ReturnedFromService)null);
MyTestableController testedController = new MyTestableController(serviceStub.Object)
{
FakeInternalMethod = true
};
// Act
testedController.MethodUnderTest();
// Assert
Assert.AreEqual(testedController.SomeDefaultValue, testedController.FakeInternalMethodWasCalledWithThisParameter);
}
private class MyTestableController
: MyController
{
public bool FakeInternalMethod { get; set; }
public string FakeInternalMethodWasCalledWithThisParameter { get; set; }
public MyTestableController(IService service)
: base(service)
{ }
internal override void InternalMethod(string someProperty)
{
if (FakeInternalMethod)
FakeInternalMethodWasCalledWithThisParameter = someProperty;
else
base.InternalMethod(someProperty);
}
}
}
The CUT could look something like this:
public class MyController : Controller
{
private readonly IService _service;
public MyController(IService service)
{
_service = service;
}
public virtual string SomeDefaultValue { get { return "SomeDefaultValue"; }}
public EmptyResult MethodUnderTest()
{
// We just found a bug in this method ...
// The method under test calls a service which returns an object.
ReturnedFromService fromService = _service.ServiceCall();
// It then calls an internal method passing a string property of this object
string someStringProperty = fromService == null
? SomeDefaultValue
: fromService.SomeProperty;
InternalMethod(someStringProperty);
return new EmptyResult();
}
internal virtual void InternalMethod(string someProperty)
{
throw new NotImplementedException();
}
}
I have a question about testing.
I have a class that returns anomalies. in this class I have two different method that simply returns two different types of anomalies and one that return all anomalies (of both types)
this is the example code:
public interface IAnomalyService
{
IList<Anomaly> GetAllAnomalies(object parameter1, object parameter2);
IList<Anomaly> GetAnomalies_OfTypeA(object parameter1);
IList<Anomaly> GetAnomalies_OfTypeB(object parameter2);
}
public class AnomalyService : IAnomalyService
{
public IList<Anomaly> GetAllAnomalies(object parameter1, object parameter2)
{
var lstAll = new List<Anomaly>();
lstAll.AddRange(GetAnomalies_OfTypeA(parameter1));
lstAll.AddRange(GetAnomalies_OfTypeB(parameter2));
return lstAll;
}
public IList<Anomaly> GetAnomalies_OfTypeA(object parameter1)
{
//some elaborations
return new List<Anomaly> { new Anomaly { Id = 1 } };
}
public IList<Anomaly> GetAnomalies_OfTypeB(object parameter2)
{
//some elaborations
return new List<Anomaly> { new Anomaly { Id = 2 } };
}
}
class Anomaly
{
public int Id { get; set; }
}
I've created the tests for the two method that retrieve the anomalies of type A and type B (GetAnomalies_OfTypeA and GetAnomalies_OfTypeB).
Now I want to test the function GetAllAnomalies but I'm not sure what I have to do.
I think I have to way for testing it:
1) declare GetAnomalies_OfTypeA and GetAnomalies_OfTypeB in class AnomalyService as virtual, make a mock of the Class AnomalyService, and using Moq I can set CallBase as true and mock the two method GetAnomalies_OfTypeA and GetAnomalies_OfTypeB.
2)move the method GetAllAnomalies in another class called AllAnomalyService (with interface IAllAnomalyService) and in its constructor I will pass an interface of IAnomalyService and after I can test the GetAllAnomalies mocking the IAnomalyService interface.
I'm new at unit testing, so I don't know which solution is better, if is one of the mines or another one.
Can you help me?
thank you
Luca
Mocking is a good tool when a class resists testing. If you have the source, mocking is often not necessary. Try this approach:
Create a factory which can return AnomalyServices with various, defined anomalies (only type A, only type B, both, none, only type C, ...)
Since the three types are connected in some way, you should check all three in each test. If only anomalies of type A are expected, you should check that GetAllAnomalies returns the same result as GetAnomalies_OfTypeA and GetAnomalies_OfTypeB returns an empty list.
I've got the following code and I need help to write a unit test for it. I'm using Moq library.
Here's the deal. I have a business class with a dependency to a repository (interface), so I can use it to save my entities to the database. My entity is basically a list of strings. The method AddAndSave, from MyBusinessClass, grab the value it receives as a parameters, put it into the list and call Save method from IRepository. Then, I clear the list of my entity. The code below show this example (I've made it simple so I can explain it here).
There's a unit test, too.
using System.Collections.Generic;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
namespace TestesGerais
{
public class MyEntity
{
public MyEntity()
{
MyList = new List<string>();
}
public List<string> MyList { get; set; }
}
public interface IRepository
{
void Save(MyEntity entity);
}
public class MyBusinessClass
{
public IRepository Repository { get; set; }
private MyEntity _entity = new MyEntity();
public void AddAndSave(string info)
{
_entity.MyList.Add(info);
Repository.Save(_entity);
_entity.MyList.Clear(); // for some reason I need to clear it
}
}
[TestClass]
public class UnitTest10
{
[TestMethod]
public void TestMethod1()
{
var mock = new Mock<IRepository>();
MyBusinessClass b = new MyBusinessClass() { Repository = mock.Object };
b.AddAndSave("xpto");
mock.Verify(m => m.Save(It.Is<MyEntity>(x => x.MyList[0] == "xpto")), Times.Exactly(1));
}
}
}
My unit-test check if the IRepository's Save method was called with its parameter (an entity) having one element in the list, and having the value "xpto" in this element.
When I run this test, it turns red with the error message "Test method TestesGerais.UnitTest10.TestMethod1 threw exception:
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index".
Ok, this is caused by the list that has been cleaned. If I comment the line "_entity.MyList.Clear();", everything goes well.
My question is: how can I test this without commenting the "Clear" line in my business class, and making sure that my repository's method is called passing the specific value (entity with one element with value "xpto")?
Thanks
I've changed my unit test using the Callback feature of Moq. This way, I can setup the mock so when AddAndSave is called, the parameter it receives is saved into a variable from my unit test, and I can assert it later.
[TestMethod]
public void TestMethod1()
{
var mock = new Mock<IRepository>();
string result = string.Empty;
mock.Setup(m => m.Save(It.IsAny<MyEntity>())).Callback((MyEntity e) => { result = e.MyList[0]; });
MyBusinessClass b = new MyBusinessClass() { Repository = mock.Object };
b.AddAndSave("xpto");
Assert.AreEqual(result, "xpto");
}
You could split your method up a bit. "AddAndSave" isn't all it does. You could then just test the behaviour of the adding and saving bit in isolation.
I'm currently learning Rhino-mocks and think I'm confusing the line between unit testing and mocking. In my example below, I have a readonly Count() property for which I am trying to test the Get() on (a very contrived example for discussion purpose only). As the comment on the Assert.AreEqual indicates, the result from the Count() property is 2 when it should be 3.
My question is can I use Rhino-mocks to actually stub an object (in this case a readonly property) and test the logic of the get_Count() property of the mock IProduct object?
public interface IProduct
{
int Count { get; }
}
public class Product : IProduct
{
private int count;
public int Count
{
get { return count + 1; }
}
}
public class TestFixture
{
[NUnit.Framework.Test]
public void TestProduct()
{
MockRepository mock = new MockRepository();
IProduct product = mock.Stub<IProduct>();
product.Stub(p => p.Count).Return(2);
mock.ReplayAll();
Assert.AreEqual(3, product.Count); //Fails - result from product.Count is 2
mock.VerifyAll();
}
}
You are mocking out the object you are trying to test. This is fundamentally incorrect--you want to mock (or stub) DEPENDENCIES on the objects you are trying to test.
In the case shown above, you would not use mocking at all.
Also see my comment on AAA syntax.