docs/articles/nunit/writing-tests/assertions/classic-assertions/Assert.ThrowsAsync.md
The Assert.ThrowsAsync is the async equivalent to Assert.Throws for asynchronous code. See Assert.Throws for more information.
Exception Assert.ThrowsAsync(Type expectedExceptionType, AsyncTestDelegate code);
Exception Assert.ThrowsAsync(Type expectedExceptionType, AsyncTestDelegate code,
string message, params object[] params);
Exception Assert.ThrowsAsync(IResolveConstraint constraint, AsyncTestDelegate code);
Exception Assert.ThrowsAsync(IResolveConstraint constraint, AsyncTestDelegate code,
string message, params object[] params);
TActual Assert.ThrowsAsync<TActual>(AsyncTestDelegate code);
TActual Assert.ThrowsAsync<TActual>(AsyncTestDelegate code,
string message, params object[] params);
In the above code AsyncTestDelegate is a delegate of the form Task AsyncTestDelegate(), which is used to execute the code in question. This will likely be a lambda expression.
The following example shows the most common way of writing tests.
[!code-csharpAssertThrowsAsync]
This example shows use of the return value to perform additional verification of the exception. Note that you do not need to await the result.
[!code-csharpAssertThrowsAsync]