Unit Testing with xUnit.net - Part 2
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The document discusses various testing concepts, including the use of class fixtures, collection fixtures, and mocks in unit testing. It emphasizes the importance of testing individual components separately to simplify tests and improve maintenance. It provides examples of implementing stubs and mocks for verifying email notifications in a testing context.
![public class EmailSvcStub : IEmailSvc
{
public int NumberOfEmailsSent { get; set; }
public void SendEmail()
{
++NumberOfEmailsSent;
}
}
[Test]
public void Trigger()
{
// setup
var emailSvc = new
EmailSvcStub(); var notifier
= new Notifier(emailSvc);
// invoke
notifier.T
rigger();
// verify
Assert.That(emailSvc.NumberOfEmailsSent,
Is.EqualTo(1));
}](https://image.slidesharecdn.com/unittestingwithxunit-170714043831/85/Unit-Testing-with-xUnit-net-Part-2-14-320.jpg)
![[Test]
public void Trigger()
{
// setup
var emailSvc = Substitute.For<IEmailSvc>();
var notifier = new Notifier(emailSvc);
// invoke
notifier.Trigger();
// verify
emailSvc.Received(1).SendEmail();
}](https://image.slidesharecdn.com/unittestingwithxunit-170714043831/85/Unit-Testing-with-xUnit-net-Part-2-15-320.jpg)
Unit Testing with xUnit.net - Part 2
- 2. • • • • •
- 6. Constructor and Dispose Class Fixtures shared object instance across tests in a single class Collection Fixtures shared object instances across multiple test classes
- 8. Assert AssertExtensions Before/After UseCulture Class Fixtures ClassFixtureExample Collection Fixtures CollectionFixtureExample Theory Data ExcelDataExample Test Ordering TestOrderExamples Traits TraitExtensibility FactAttribute TheoryAttribute Test frameworks Runners
- 10. Mock objects Do behavioral assertions for SUT Only cares about whether the unit to be tested is correct Do not care about the correctness of DOC Test Code SUT DOC DON’T CARE!!
- 11. ● ● replace the real Y with a fake Y ● Benefits ● ● ● Only test one thing (X) at a time Faster tests (Y may be slow) Simpler (Y may depend on Z etc) ● Examples: ● ● ● ● Time Database Email HttpContext Notifier EmailSvc IEmailSvc EmailSvcStub NotifierTest When testing an object X, that depends on an object Y
- 12. ● Hand crafted ● More effort to write ● Easier to maintain ● Can be more "black box" than mocks
- 13. ● Mocks are automatically generated stubs ● Easy to use ● More "magical" ● More effort to maintain
- 14. public class EmailSvcStub : IEmailSvc { public int NumberOfEmailsSent { get; set; } public void SendEmail() { ++NumberOfEmailsSent; } } [Test] public void Trigger() { // setup var emailSvc = new EmailSvcStub(); var notifier = new Notifier(emailSvc); // invoke notifier.T rigger(); // verify Assert.That(emailSvc.NumberOfEmailsSent, Is.EqualTo(1)); }
- 15. [Test] public void Trigger() { // setup var emailSvc = Substitute.For<IEmailSvc>(); var notifier = new Notifier(emailSvc); // invoke notifier.Trigger(); // verify emailSvc.Received(1).SendEmail(); }