Unit Testing Redux Slide 1

Unit TestingUnit Testing"Beware of bugs in the above code; "Beware of bugs in the above code;

I have only proved it correct, not tried it."I have only proved it correct, not tried it." – Donald E. Knuth, March 29, 1977 in a note to Peter van Emde Boas titled

Notes on the van Emde Boas construction of priority deques: An instructive use of recursion

Unit Testing Redux Slide 2

Unit Test – What is it?Unit Test – What is it?

A unit test is a method used to verify that particular small unit of code (class) is working properly.

Each test case is separate from the others so that only the functions provided by the class are evaluated.

Unit Testing Redux Slide 3

Unit Test CharacteristicsUnit Test Characteristics

AutomaticRequires neither intervention nor manual setup

ThoroughCovers all important functionality, including protected and private methods. Boundary conditions should be checked.

RepeatableTests run with the same data return the same results.

Unit Testing Redux Slide 4

Unit Test CharacteristicsUnit Test Characteristics

IndependentEach test is independent of the results of previous tests and do not affect later tests.

PerformantPerformance is good enough to support running many tests at one session.

Unit Testing Redux Slide 5

Unit Test TerminologyUnit Test Terminology

A Test Fixture is a public instance class having the TestClass attribute.

A Test is a non-static public method returning void, accepting no parameters and having the Test attribute.

A Test Context is an instance of the TestContext class that persists throughout the life of a test fixture.

Unit Testing Redux Slide 6

Unit Test TerminologyUnit Test Terminology

The Unit Test Runner is the code that instantiates test fixtures, executes tests within the fixture capturing output and exceptions (assertions).

The Visual Studio Test Manager manages lists of tests and fixtures to be submitted to the test runner.

Unit Testing Redux Slide 7

Unit Test LifecycleUnit Test Lifecycle

Text FixtureTest RunnerTest RunnerLoad the classLoad the class

•Inspect metadata to find all tests.Inspect metadata to find all tests.•Copy all deployment itemsCopy all deployment items•Invoke assembly initialize methodInvoke assembly initialize method•Invoke class initialize method Invoke class initialize method

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Unit Test LifecycleUnit Test Lifecycle

Text FixtureTest RunnerTest Runner

For each test For each test method create an method create an instanceinstance

•Invoke the test initialize method.Invoke the test initialize method.•Call the test methodCall the test method•Invoke the test cleanup methodInvoke the test cleanup method

Unit Testing Redux Slide 9

Unit Test LifecycleUnit Test Lifecycle

Text FixtureTest RunnerTest Runner

•Invoke the class cleanup methodInvoke the class cleanup method•Invoke assembly cleanup methodInvoke assembly cleanup method

Unit Testing Redux Slide 10

Life Cycle of a Unit Test FixtureLife Cycle of a Unit Test Fixture

An instance of the unit test runner is created (either through VS or MSTest)

The test runner loads the test fixture and inspects the test attributes using reflection.

From the test information, a test context instance is created. This instance exists throughout the life of the text fixture.

The assembly and class initialize methods are called (static methods with AssemblyIntitialize and ClassInitialize attributes).

Unit Testing Redux Slide 11

Life Cycle of a Unit Test FixtureLife Cycle of a Unit Test Fixture

For each test (method) in the fixture, the following RUN procedure occurs: An instance of the test fixture is created. A copy of the test context is passed to the fixture

instance. Instance information is now in the test context.

The initialize method is called (a method with the TestInitialize attribute).

The test method is invoked The cleanup method is called (a method with the

TestCleanup attribute).

Unit Testing Redux Slide 12

Life Cycle of a Unit Test FixtureLife Cycle of a Unit Test Fixture

When all tests have run (or until the runner terminates) The class cleanup method (a static method with the

ClassCleanup attribute) is called. The assembly cleanup method (a static method with

the AssemblyCleanup attribute) is called.

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Life Cycle of a Unit Test FixtureLife Cycle of a Unit Test Fixture

If the test has a data source associated with it, then the following occurs: While there are more rows in the data source,

populate the DataRow property with the next row in the data source and then execute the RUN procedure.

If a test throws an exception (via an assertion or otherwise), the test is terminated with a failure.

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Testing Non-Public MethodsTesting Non-Public Methods

Visual Studio uses reflection to create accessor classes; the file is VSGenCodeAccessors.cs – do not modify!

It has the same namespace as your test container (test project)

Modify Visual Studio generated code within your test method for readability.

Unit Testing Redux Slide 15

Testing Non-Public MethodsTesting Non-Public Methods

Create a instance of your class using the public constructor.

Pass the object to accessor constructor. Call methods on the returned accessor. _matrix = new Matrix(new Collection<string>(headerLabels)); Digatto_Covering_Dlx_MatrixAccessor matrix = new Digatto_Covering_Dlx_MatrixAccessor(_matrix); matrix.PopulateRow(new Collection<string>(new string[] { "C", "E", "F" }));

Unit Testing Redux Slide 16

Best PracticesBest Practices Use the test context to store information that

must be shared by different tests. The Properties property returns an IDictionary object.TotalAgents:1ControllerName:BXLEVAROAgentWeighting:100AgentName:BXLEVAROTestDeploymentDir:C:\Documents and Settings\richard.levaro\Local Settings\Application Data\

VSEqtDeploymentRoot\f4e70d35-26e9-4c28-96c9-9a1891bf72bc\OutAgentId:1TestLogsDir:C:\Documents and Settings\richard.levaro\Local Settings\Application Data\

VSEqtDeploymentRoot\f4e70d35-26e9-4c28-96c9-9a1891bf72bc\In\BXLEVAROTestDir:C:\Documents and Settings\richard.levaro\Local Settings\Application Data\

VSEqtDeploymentRoot\f4e70d35-26e9-4c28-96c9-9a1891bf72bcTestName:AddBookTest

To include output in the test details, use the WriteLine method of the test context.

Use the initialize and cleanup methods

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Best PracticesBest Practices

Don’t test the framework (or Hibernate) Do test your algorithms; create mock

objects if necessary Do use unit testing as software scaffolding

during development and then migrate to a unit test

Don’t test trivia (Properties that don’t do anything)

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Best PracticesBest Practices

Visual Studio places the test project in the same location as the source.

Create the test project first and then add tests to it.

Use the “Test Tools” toolbar

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Integration with Team SuiteIntegration with Team Suite

MSTest allows unit tests to be run as part of the build project.

Create work items based upon failed results.

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DocumentationDocumentation

Contains all documentation for Assert methods

Attribute documentation Found in Team Test API under Team

Edition for Testers Other namespaces implement load

testing, Web testing and others

Microsoft.VisualStudio.TestTools.UnitTestingMicrosoft.VisualStudio.TestTools.UnitTesting

Unit Testing Redux Slide 21

There’s More …There’s More …

Data-driven tests and how to create them Code coverage Detailed Team System integration –

publishing test results