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My project/Library/PackageCache/com.unity.test-framework/Documentation~/course/custom-attributes.md

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+# 16\. Custom attributes
+
+## Learning objectives
+
+In this section we will look at some ways of implementing custom NUnit attributes, which can be used to alter test execution.
+
+## Intro and motivation
+
+A powerful part of NUnit is that it is very extendable. One of the ways it can be extended is through custom attributes. An example is attributes that implement the [IWrapTestMethod](https://docs.nunit.org/articles/nunit/extending-nunit/ICommandWrapper-Interface.html) interface. This interface has a method for wrapping a `TestCommand`, which implements a method for executing. Normally these test commands do something, call execute on their inner command and then maybe do something again after the inner command is completed.  
+  
+In the following three classes an `IWrapTestMethod` interface is implemented and used in a test:  
+
+```
+public class MyAttribute : NUnitAttribute, IWrapTestMethod
+{
+ public TestCommand Wrap(TestCommand command)
+ {
+  return new MyCommand(command);
+ }
+}
+
+public class MyCommand : TestCommand
+{
+ private TestCommand innerCommand;
+ 
+ public MyCommand(TestCommand command) : base(command.Test)
+ {
+  innerCommand = command;
+ }
+
+ public override TestResult Execute(ITestExecutionContext context)
+ {
+  Debug.Log("Before");
+  var result = innerCommand.Execute(context);
+  Debug.Log("After");
+
+  return result;
+ }
+}
+
+public class MyTests
+{
+ [Test]
+ [MyAttribute]
+ public void Test1()
+ {
+  Debug.Log("The test");
+ }
+}
+```  
+
+When running `MyTests.Test1` the following output is printed:  
+
+Test1 (0,017s)  
+\---  
+Before  
+The test  
+After
+
+Other interfaces that custom attributes can implement are `IWrapSetUpTearDown`, `IApplyToContext`, and `IApplyToTest`.
+
+## Exercise
+
+At Unity we have a goal that an action should never take longer than 500 ms. In the [sample](./welcome.md#import-samples) `16_CustomAttributes` there is a class called `MyClass`, which has two methods. Both methods are supposed to return true. However someone has made a regression so that one of the two methods takes a long time to run.  
+  
+The task is to create a new custom attribute, which detects if the test takes longer than 500 ms to run. If that happens, it should fail the test with a descriptive message. Apply that to the two existing tests.
+
+## Hints
+
+*   You can use the class `System.Diagnostics.Stopwatch` to time how many miliseconds have passed.
+
+## Solution
+
+A full solution for the exercise is availiable at `16_CustomAttributes_Solution`.  
+  
+The core of the solution is the execute method in the test command implementation:  
+
+```
+public override TestResult Execute(ITestExecutionContext context)
+{
+ var stopWatch = new Stopwatch();
+ stopWatch.Start();
+ var result = innerCommand.Execute(context);
+ stopWatch.Stop();
+
+ if (stopWatch.ElapsedMilliseconds > 500)
+ {
+  result.SetResult(ResultState.Failure, $"Test took {stopWatch.ElapsedMilliseconds} ms. That is longer than 500ms!");
+ }
+
+ return result;
+}
+```