Is there a way to run an identical set of tests over multiple objects, but toggle each test depending on the type of said objects?
i.e. if I had classes
abstract class MyObj{ abstract bool DoWork(bool isTrue); }
class SubObj1 : MyObj{ override bool DoWork(bool IsTrue){return IsTrue; } }
class SubObj2 : MyObj{ override bool DoWork(bool IsTrue){return false; } }
and tests
class Tests
{
[Test]
void Test1() { Assert.IsTrue(new SubObj1().DoWork(true)) }
[Test]
void Test2() { Assert.IsTrue(new SubObj1().DoWork(false)) }
}
I'd like to be able to use flags, type checking, or something so that I:
could replace the references to SubObj1 with a MyObj instance,
Run the class Tests over both SubObj1 and SubObj2, but prevent Test1 from running if working with a SubObj2 instance? EDIT: This part can be done with Assert.Ignore.
(The real case in my code involves three different unstructured-data parsers, each of which trade simplicity for accuracy in a different way. I have 400 test cases for one parser, and would like to port them to the other two. Creating three nearly identical sets of tests cases and pruning the tests that don't work in each class seems like a massive DRY failure.)
You can do it very easy with TestCaseSourceAttribute. Something like:
class Tests
{
static object[] TestCases = new object[]
{
new object[] { new SubObj1(), true }
new object[] { new SubObj2(), false}
};
[Test, TestCaseSource("TestCases")]
void Test1(MyObj obj, bool isTrue) { Assert.IsTrue(obj.DoWork(isTrue)) }
}
(I did not try to compile it, just shared the basic idea).
Related
Please note, I'm somewhat new to TDD, so I will take general advice as well as specific answer.
Neither abstract classes nor interfaces can be instantiated. Clearly Moq can give me a mocked up instance of the ADataFeed in the second test. Why does AutoMoqCustomization work for interfaces IDataFeed but not for abstract classes ADataFeed, instead throwing an InvalidOperationException?
Secondarily, what would be the AutoFixture approach (or TDD generally) be to drive a design that might call for an abstract class with a constructor to require and guarantee certain values, such as a connection string in this case?
[Theory, AutoMoqData]
public void AllDataFeedsHaveAConectionString(
IDataFeed sut)
{
var result = sut.GetConnectionString();
Assert.Null(result);
}
[Fact]
public void AllDataFeedsRequireAConnectionString()
{
var expected = Guid.NewGuid().ToString();
var sut = new Mock<ADataFeed>(expected);
var result = sut.Object.GetConnectionString();
Assert.Equal(expected, result);
}
[Theory, AutoMoqData]
public void AllDataFeedsRequireAConnectionString2(
[Frozen] string expected,
ADataFeed sut)
{
var result = sut.GetConnectionString();
Assert.Equal(expected, result);
}
Abstract classes with constructors must be marked protected. AutoFixture will not program against abstract classes when the constructor is marked public, as this is a design error.
I am having two Methods in Unit Test case where First Insert Records into Database and Second retrieves back data. I want that input parameter for retrieve data should be the id generated into first method.
private int savedrecordid =0;
private object[] SavedRecordId{ get { return new object[] { new object[] { savedrecordid } }; } }
[Test]
public void InsertInfo()
{
Info oInfo = new Info();
oInfo.Desc ="Some Description here !!!";
savedrecordid = InsertInfoToDb(oInfo);
}
[Test]
[TestCaseSource("SavedRecordId")]
public void GetInfo(int savedId)
{
Info oInfo = GetInfoFromDb(savedId);
}
I know each test case executed separately and separate instance we can't share variables across test methods.
Please let me know if there is way to share parameters across the test cases.
The situation you describe is one of unit tests' antipatterns: unit tests should be independent and should not depend on the sequence in which they run. You can find more at the xUnit Patterns web site:
Unit test should be implemented using Fresh Fixture
Anti pattern Shared Fixture
And both your unit tests have no asserts, so they can't prove whether they are passing or not.
Also they are depend on a database, i.e. external resource, and thus they are not unit but integration tests.
So my advice is to rewrite them:
Use mock object to decouple from database
InsertInfo should insert info and verify using the mock that an appropriate insert call with arguments has been performed
GetInfo should operate with a mock that returns a fake record and verify that it works fine
Example
Notes:
* I have to separate B/L from database operations…
* … and make some assumptions about your solution
// Repository incapsulates work with Database
public abstract class Repository<T>
where T : class
{
public abstract void Save(T entity);
public abstract IEnumerable<T> GetAll();
}
// Class under Test
public class SomeRule
{
private readonly Repository<Info> repository;
public SomeRule(Repository<Info> repository)
{
this.repository = repository;
}
public int InsertInfoToDb(Info oInfo)
{
repository.Save(oInfo);
return oInfo.Id;
}
public Info GetInfoFromDb(int id)
{
return repository.GetAll().Single(info => info.Id == id);
}
}
// Actual unittests
[Test]
public void SomeRule_InsertInfo_WasInserted() // ex. InsertInfo
{
// Arrange
Info oInfo = new Info();
oInfo.Desc = "Some Description here !!!";
var repositoryMock = MockRepository.GenerateStrictMock<Repository<Info>>();
repositoryMock.Expect(m => m.Save(Arg<Info>.Is.NotNull));
// Act
var savedrecordid = new SomeRule(repositoryMock).InsertInfoToDb(oInfo);
// Assert
repositoryMock.VerifyAllExpectations();
}
[Test]
public void SomeRule_GetInfo_ReciveCorrectInfo() // ex. GetInfo
{
// Arrange
var expectedId = 1;
var expectedInfo = new Info { Id = expectedId, Desc = "Something" };
var repositoryMock = MockRepository.GenerateStrictMock<Repository<Info>>();
repositoryMock.Expect(m => m.GetAll()).Return(new [] { expectedInfo }.AsEnumerable());
// Act
Info receivedInfo = new SomeRule(repositoryMock).GetInfoFromDb(expectedId);
// Assert
repositoryMock.VerifyAllExpectations();
Assert.That(receivedInfo, Is.Not.Null.And.SameAs(expectedInfo));
}
ps: full example availabel here
I want to mock a Class in Mockito. It will then have a .newInstance() call issued which will be expected to return an actual class instance (and will return a mock in my case).
If it was setup correctly then I could do:
ArrayList myListMock = mock(ArrayList.class);
when(myVar.newInstance()).thenReturn(myListMock);
I know I can set it up so that a new instance of class ArrayList will be a mock (using PowerMockito whenNew), just wondering if there was a way to mock this kind of a class object so I don't have to override instance creation...
Below is the real class I'm trying to mock, I can't change the structure it is defined by the interface. What I'm looking for is a way to provide cvs when initialize is called.
public class InputConstraintValidator
implements ConstraintValidator<InputValidation, StringWrapper> {
Class<? extends SafeString> cvs;
public void initialize(InputValidation constraintAnnotation) {
cvs = constraintAnnotation.inputValidator();
}
public boolean isValid(StringWrapper value,
ConstraintValidatorContext context) {
SafeString instance;
try {
instance = cvs.newInstance();
} catch (InstantiationException e) {
return false;
} catch (IllegalAccessException e) {
return false;
}
}
Mockito is designed exclusively for mocking instances of objects. Under the hood, the mock method actually creates a proxy that receives calls to all non-final methods, and logs and stubs those calls as needed. There's no good way to use Mockito to replace a function on the Class object itself. This leaves you with a few options:
I don't have experience with PowerMock but it seems it's designed for mocking static methods.
In dependency-injection style, make your static factory method into a factory instance. Since it looks like you're not actually working with ArrayList, let's say your class is FooBar instead:
class FooBar {
static class Factory {
static FooBar instance;
FooBar getInstance() {
if (instance == null) {
instance = new FooBar();
}
return instance;
}
}
// ...
}
Now your class user can receive a new FooBar.Factory() parameter, which creates your real FooBar in singleton style (hopefully better and more threadsafe than my simple implementation), and you can use pure Mockito to mock the Factory. If this looks like it's a lot of boilerplate, it's because it is, but if you are thinking of switching to a DI solution like Guice you can cut down a lot of it.
Consider making a field or method package-private or protected and documenting that it's visible for testing purposes. Then you can insert a mocked instance in test code only.
public class InputConstraintValidator implements
ConstraintValidator<InputValidation, StringWrapper> {
Class<? extends SafeString> cvs;
public void initialize(InputValidation constraintAnnotation) {
cvs = constraintAnnotation.inputValidator();
}
public boolean isValid(StringWrapper value,
ConstraintValidatorContext context) {
SafeString instance;
try {
instance = getCvsInstance();
} catch (InstantiationException e) {
return false;
} catch (IllegalAccessException e) {
return false;
}
}
#VisibleForTesting protected getCvsInstance()
throws InstantiationException, IllegalAccessException {
return cvs.newInstance();
}
}
public class InputConstaintValidatorTest {
#Test public void testWithMockCvs() {
final SafeString cvs = mock(SafeString.class);
InputConstraintValidator validator = new InputConstraintValidator() {
#Override protected getCvsInstance() {
return cvs;
}
}
// test
}
}
I think you just need to introduce an additional mock for Class:
ArrayList<?> myListMock = mock(ArrayList.class);
Class<ArrayList> clazz = mock(Class.class);
when(clazz.newInstance()).thenReturn(myListMock);
Of course the trick is making sure your mocked clazz.newInstance() doesn't end up getting called all over the place because due to type-erasure you can't specify that it's actually a Class<ArrayList>.
Also, be careful defining your own mock for something as fundamental as ArrayList - generally I'd use a "real one" and populate it with mocks.
I'm trying to verify that a method within a mock is called with an expected object parameter. I'm using Moq, nUnit, and thinking that AutoFixture's Likeness should get the job done.
Below is a simplified version of what i'm trying to do.
Is there a way to do this with AutoFixture? Is there a better way to verify that Something is called with the appropriate parameter?
Overriding Equals in the A class to compare the property values and changing the Verify line to:
barMock.Verify(m => m.Something(a));
passes, however I'd rather not override Equals in every class like A in my project.
namespace Test
{
using Moq;
using NUnit.Framework;
using Ploeh.SemanticComparison.Fluent;
public class A
{
public int P1 { get; set; }
}
public interface IBar
{
void Something(A a);
}
public class Foo
{
public A Data { get; private set; }
public void DoSomethingWith(IBar bar)
{
Data = new A { P1 = 1 };
bar.Something(Data);
}
}
[TestFixture]
public class AutoFixtureTest
{
[Test]
public void TestSample()
{
var foo = new Foo();
var barMock = new Mock<IBar>();
var a = new A { P1 = 1 };
var expectedA = a.AsSource().OfLikeness<A>();
foo.DoSomethingWith(barMock.Object);
expectedA.ShouldEqual(foo.Data); // passes
barMock.Verify(m => m.Something(expectedA.Value)); // fails
}
}
}
In Verify Moq by default checks reference equality for arguments so it only passes when you provide the same instances (except if you've overriden Equals) in your tests and in your implementation.
In you case the expectedA.Value just returns the new A { P1 = 1 } created in the test which, of course, isn't the same instance created in DoSomethingWith.
You need to use Moq's It.Is construct to properly test this without overriding Equals (in fact for this you don't need Autofixture at all):
barMock.Verify(m => m.Something(It.Is<A>(arg => arg.P1 == a.P1)));
But if you have multiple properties like P1,P2,P3... AutoFixture can be useful:
barMock.Verify(m => m.Something(It.Is<A>(arg => expectedA.Equals(a))));
Because you don't need to write out the equality checks manually for all the properties.
If you upgrade to AutoFixture 2.9.1 (or newer) you can call the CreateProxy method on the Likeness instance which will emit a dynamic proxy for the destination type.
The generated dynamic proxy overrides Equals using Likeness which simplifies the syntax (quite a lot).
Here is the original test method, modified to use the Likeness proxy:
[Test]
public void TestSample()
{
var foo = new Foo();
var barMock = new Mock<IBar>();
var expected = new A().AsSource().OfLikeness<A>().CreateProxy();
expected.P1 = 1;
foo.DoSomethingWith(barMock.Object);
Assert.True(expected.Equals(foo.Data)); // passes
barMock.Verify(m => m.Something(expected)); // passes
}
Note that it also makes the test assertion much more specific than accepting Any instance.
You can find more details on this new feature here.
Example A:
// pseudo code
interface IFoo {
void bar();
}
class FooPlatformA : IFoo {
void bar() { /* ... */ }
}
class FooPlatformB : IFoo {
void bar() { /* ... */ }
}
class Foo : IFoo {
IFoo m_foo;
public Foo() {
if (detectPlatformA()} {
m_foo = new FooPlatformA();
} else {
m_foo = new FooPlatformB();
}
}
// wrapper function - downside is we'd have to create one
// of these for each function, which doesn't seem right.
void bar() {
m_foo.bar();
}
}
Main() {
Foo foo = new Foo();
foo.bar();
}
Example B:
// pseudo code
interface IFoo {
void bar();
}
class FooPlatformA : IFoo {
void bar() { /* ... */ }
}
class FooPlatformB : IFoo {
void bar() { /* ... */ }
}
class FooFactory {
IFoo newFoo() {
if (detectPlatformA()} {
return new FooPlatformA();
} else {
return new FooPlatformB();
}
}
}
Main() {
FooFactory factory = new FooFactory();
IFoo foo = factory.newFoo();
foo.bar();
}
Which is the better option, example A, B, neither, or "it depends"?
I would say that your explicit factory option (option B) is generally better.
In your first example your Foo class is effectively doing two jobs, it's a factory and it's a proxy. Two jobs, one class, makes me uneasy.
Your second option puts a little more responsibility on the client: they need to know to use the factory, but this is such a widely used idiom that I think it's not hard to understand.
The problem with A is that you have to implement every method of IFoo in Foo. That is not a big deal if there are only a couple, but is a pain if there are dozens of them. If you are working with a language that supports factory methods, such as Curl, then you could put a factory method in IFoo:
{define-class abstract IFoo
{method abstract {bar}:void}
{factory {default}:{this-class}
{if platformA? then
{return {FooPlatformA}}
else
{return {FooPlatformB}}
}
}
}
{define-class FooPlatformA {inherits IFoo}
{method {bar}:void}
}
...
def foo = {IFoo}
{foo.bar}
If you ask me B is way better - since Foo itself does not need to do any switching on platform. Why does that matter? Well, since you probably want to test all components separately - Foo with a 'test' IFoo, FooPlatformA separately on platform A and FooPlatformB on platform B. If you stick the choice inside Foo you need to test Foo on both A and B, not only the different IFoos. Makes the components more coupled for no apparent reason.
The factory is a cleaner solution as you do not have implement each member of the interface in the wrapper class Foo : IFoo. Imagine, each time you modify the IFoo interface you would need update the wrapper. When programming, depending on your goals, try to consider maintainability as much as possible.
Are all 'platforms' available or only one of them? Is the only difference between the platforms is logic? Thinking from a game developer perspective I would use #defines to implement this.
class Platform : IPlatform
{
void Update()
{
#if PLATFORM_A
* ... Logic for platform A */
#elif PLATFORM_B
* ... Logic for platform A */
#endif
}
}
HTH,
Interfaces are used when it is possible that multiple implementations of a single functional set may exist. This sounds as though it applies to your particular scenario.
In terms of your examples, I would definitely roll with B, it is easier to maintain. A embeds too much common logic [ie platform detection] within individual classes [and/or methods]. If you are to build your own Factory class, try to generalize it [through a generic Resolve<IType> () method or something], as opposed to a method\class per interface.
For instance,
// i called it a "container" because it "contains" implementations
// or instantiation methods for requested types - but it *is* a
// factory.
public class Container
{
// "resolves" correct implementation for a requested type.
public IType Resolve<IType> ()
{
IType typed = default (IType);
if (isPlatformA)
{
// switch or function map on IType for correct
// platform A implementation
}
else if (isPlatformB)
{
// switch or function map on IType for correct
// platform B implementation
}
else
{
// throw NotSupportedException
}
return typed;
}
}
However, rather than implement your own Factory pattern, you may wish to investigate alternative implementations, such as MS's Unity2.0 or Castle Windsor's CastleWindsorContainer. These are easy to configure and consume.
Ideally,
// use an interface to isolate *your* code from actual
// implementation, which could change depending on your needs,
// for instance if you "roll your own" or switch between Unity,
// Castle Windsor, or some other vendor
public interface IContainer
{
IType Resolve<IType> ();
}
// custom "roll your own" container, similar to above,
public class Container : IContainer { }
// delegates to an instance of a Unity container,
public class UnityContainer : IContainer { }
// delegates to an instance of a CastleWindsorContainer,
public class CastleWindsorContainer : IContainer { }
Oh, suppose I ought to shout out to Ninject and StructureMap too. I am just not as familiar with these as with Unity or CastleWindsor.