Using Rhino Mocks for Effective Unit Testing

Using Rhino Mocks for Effective Unit Testing,[object Object],Mike Clement,[object Object],Utah Code Camp,[object Object],Spring 2011,[object Object],mike@softwareontheside.com,[object Object],@mdclement,[object Object]

Unit Testing Defined,[object Object],“A piece of code that invokes another piece of code and checks the correctness of some assumptions afterward.”,[object Object]

Good Unit Tests,[object Object],Automated and repeatable,[object Object],Easy to implement,[object Object],Remain for future use,[object Object],Anyone should be able to run it,[object Object],Run easily (push of a button),[object Object],Run quickly,[object Object]

Simple Unit Tests,[object Object],No dependencies,[object Object]

Simple Unit Test Demo,[object Object],Prime Factors,[object Object]

More Complex Unit Tests,[object Object],Simple only gets you so far,[object Object],Need more sophisticated mechanisms,[object Object],Isolation or Mocking Frameworks to the rescue!,[object Object],Does necessitate classes/methods designed for testing,[object Object]

Test Doubles,[object Object],Dummy objects are passed around but never actually used. Usually they are just used to fill parameter lists.,[object Object],Fake objects actually have working implementations, but usually take some shortcut which makes them not suitable for production (an in memory database is a good example).,[object Object]

More Test Doubles (Stubs),[object Object],Stubs provide canned answers to calls made during the test, usually not responding at all to anything outside what's programmed in for the test. Stubs may also record information about calls, such as an email gateway stub that remembers the messages it 'sent', or maybe only how many messages it 'sent'.,[object Object],In Rhino Mocks:,[object Object],an object that you use in order to pass to the code under test. ,[object Object],expectations will never be verified. ,[object Object],properties will automatically behave like normal properties, and you can't set expectations on them.,[object Object],IMPORTANT: A stub will never cause a test to fail.,[object Object],MockRepository.GenerateStub<T>(),[object Object]

Rhino Mocks Features,[object Object],Choice of "Arrange, Act, and Assert" or "Explicit record, replay, and verify" models for expectations.,[object Object],Support for Generics, C# Lambda expressions, and other C# 3.0 and .NET 3.5 features,[object Object],Working with strongly typed mocks.,[object Object],Expectations based on:,[object Object],Arguments matching,[object Object],Constraints matching,[object Object],Custom callback to verify the expected arguments using your own code,[object Object],Calling your delegates to decide what to do,[object Object],Setting actions on methods, return specific value, or throw an exception.,[object Object],Much more.,[object Object]

Simple and Inline Constraints,[object Object],Specify,[object Object],repository.Stub(x => x.UpdateSession(session)),[object Object],Ignore All,[object Object],IgnoreArguments(),[object Object],Arg<T>.Is.Anything,[object Object],Arg<T>.Is.Null,[object Object]

Arg Constraints,[object Object],Arg<T>.Is,[object Object],Equal(object), NotEqual(object) Comparison using Equals,[object Object],GreaterThan(object), LessThan(object), LessThanOrEqual(object), GreaterThanOrEqual(object) Comparison using >, <, >= and <= operators,[object Object],Same(object), NotSame(object) Reference equality,[object Object],Anything() No constraints,[object Object],Null(), NotNull() Reference is null or not null,[object Object],TypeOf(Type), TypeOf<T>() Argument is of a certain type,[object Object],Matching<T>(Predicate<T>) Argument matches a predicate (.NET 3.5: see Arg<T>.Matches). Example: Arg<string>.Is.Matching(delegate(string s) { return s.Length == 2; },[object Object],IsIn(object) Enumerable argument includes the specified object,[object Object],Arg<T>.List,[object Object],OneOf(IEnumerable) Argument is in the specified list,[object Object],Equal(IEnumerable) All items in the enumerable argument are compared to the items in the specified list.,[object Object],Count(AbstractConstraint) Constraints to the Count property of the argument.,[object Object],Element(int, AbstractConstraint) Element at the specified index meets the constraint.,[object Object],ContainsAll(IEnumerable) The enumerable argument contains at least the specified items.,[object Object],Arg<T>.Property,[object Object],AllPropertiesMatch(object) All the public properties and public fields are compared to the properties in the specified object. The comparesion is recusive if public properties or fields are complex types.,[object Object],IsNotNull(string propertyName), IsNull(string propertyName) Property of the given name is or is not null,[object Object],Value(string propertyName, object expectedValue) The property of the given name is equal to the expected value.,[object Object],Value(string propertyName, AbstractConstraint constraint) Property of the given Name meets the constraint.,[object Object],Arg.Text,[object Object],StartsWith(string), EndsWith(string), Contains(string) String starts with, ends with or contains the specified text,[object Object],Like(string regex) Property matches to the regular expression,[object Object],Arg<T>.Matches,[object Object],Arg<T>.Matches(Expression) Only in .NET 3.5 you can specify the constraint as a lambda expression, e.g. Arg<int>.Matches(x => x > 3),[object Object],Arg<T>.Matches(AbstractConstraint) Specify Rhino Mocks Constraints, e.g. Arg<int>.Matches(Is.GreaterThan(0) && Is.LessThan(10)),[object Object],http://www.ayende.com/wiki/Rhino+Mocks+3.5.ashx#ConstraintsReference,[object Object]

More Test Doubles (Mocks),[object Object],Mocks are objects pre-programmed with expectations which form a specification of the calls they are expected to receive.,[object Object],An object that we can set expectations on, and which will verify that the expected actions have indeed occurred. ,[object Object],http://martinfowler.com/articles/mocksArentStubs.html,[object Object]

Mocks,[object Object],Strict vs. Dynamic,[object Object],Use Dynamic Mocks… Strict not recommended,[object Object],MockRepository.GenerateMock<T>(),[object Object]

Events!,[object Object],[Test] ,[object Object],public void RaisingEvent () ,[object Object],{ ,[object Object],varmocks = new MockRepository();,[object Object],IView view = mocks.DynamicMock<IView>();,[object Object],Presenter p = new Presenter(view);view.Raise(x => x.Load += null, this, EventArgs.Empty);Assert.IsTrue(p.OnLoadCalled); ,[object Object],},[object Object]

Good Unit Testing Resources!,[object Object],The Art of Unit Testing: With Examples in .Net,[object Object],Pragmatic Unit Testing in C# with NUnit, 2nd Edition,[object Object],http://www.ayende.com/wiki/Rhino+Mocks.ashx,[object Object]

Thank you to our sponsors!,[object Object],Platinum Sponsors,[object Object],Gold Sponsors,[object Object],Silver Sponsors,[object Object],Bronze Sponsors,[object Object]

Using Rhino Mocks for Effective Unit Testing

Using Rhino Mocks for Effective Unit Testing

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Using Rhino Mocks for Effective Unit Testing