Assert in XUnit. That’s the exception type returned from async methods; it wraps the actual exception. xUnit Assert.Throws and Record.Exception does not catch exception. JUnit 4. You’ll end up with an AggregateException every time. 3. Call a utility method to evaluate whether an expected outcome has been achieved. Test for Exceptions using xUnit's Assert.Throws xUnit kindly provides a nice way of capturing exceptions within our tests with Assert.Throws. When using JUnit 4, we can simply use the expected attribute of the @Test annotation to declare that we expect an exception to be thrown anywhere in the annotated test method. A very extensive set of extension methods that allow you to more naturally specify the expected outcome of a TDD or BDD-style unit tests. Hot Network Questions Why do Hilton Garden Inns have color printers guests can use freely, … The assertThrows() method enables more fine-grained control for exception assertion logic because we can use it around specific parts of the code. The assertion library is optional in 2.x, so if you don't like our assertions, you can remove the xunit.assert NuGet package, and use one of the plethora of third party assertion libraries. Targets .NET Framework 4.5 and 4.7, .NET Core 2.0 and 2.1, as well as .NET Standard 1.3, 1.6, 2.0 and 2.1. I still miss the DoesNotThrow method from NUnit for one reason: explicity. As part of a try/catch (or equivalent) block in an Expected Exception Test (see Test Method) by including a call to fail in the try block right after the call that is expected to throw an exception. In this post I’m going to focus on assertions that check whether or not something happened. You're supposed to await the result (see xunit's acceptance tests). [Fact] public async Task Test1() { await Assert.ThrowsAsync(() => MethodThatThrows()); } In this specific degenerate case, you could just return the Task that Assert.ThrowsAsync yields without using await, but the key thing is you need to hand the resulting Task back to the xUnit framework, i.e. To do this the xUnit.net Assert.Throws method can be used. Forcing the tests using .Result doesn’t work so great when you want to test for a certain type of exception to be thrown. Example An assertion is a boolean expression at a specific point in a program which will be true unless there is a bug in the program. All we need to do is supply Assert.Throws with an exception type, and an Action that is supposed to throw an exception. When using this method the generic type parameter indicates the type of expected exception and the method parameter takes an action that should cause this exception to be thrown, for example: XUnit – Part 3: Action Based Assertions Assert.Raises and Assert.Throws In my previous post , we saw how value and type based assertions works in xUnit. The ExpectedException object is created as a rule that expects none exception is thrown so this rule doesn’t affect all existing test methods: @Rule public ExpectedException exception = ExpectedException.none(); Then in the test method you can use its expect() and expectMessage() to assert the type of expected exception and the exception message. 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