How to write a unit test that checks that an exception is thrown?
Other answers have addressed the general problem of how to write a unit test that checks that an exception is thrown. But I think your question is really asking about how to get the code to throw the exception in the first place. Take your code as an example.
How to handle error handling in unit testing?
Unit Testing Error Handling and Exceptions 1 Do nothing. Sometimes our code is not supposed to handle errors. Someone else will take care of it, in our case A. 2 Transform and throw. This is not Optimus Prime’s call to action, but an exception handling mechanism. 3 Handle it. The final option is to do some actual error handling.
When to throw an exception in C #?
If the test runner completes the test without throwing an exception or failing an Assert, the test passes. Next, we provide the type argument, which needs to be a type of Exception, the type of exception we expect our code to throw, ArgumentOutOfRangeException.
Can a test fail if an exception is thrown?
Although the test would fail if an exception is thrown even if there was no Assert around it, the value of this approach is that you can then distinguish between unmet expectations and bugs in your tests, and you have the option of adding a custom message that will be displayed in your test output.
How to do unit test for exceptions in Java?
Alternately, you can use the Exception Annotation to note that you expect an exception to come out. Now, as to you specific example, Testing that something you are creating inside your method, either via new or statically as you did, when you have no way to interact with the object is tricky.
Is it worth it to do a unit test?
You need to make a case-by-case judgement as to whether it is worth the effort of doing this; i.e. does the benefit of the unit test outweigh the work (and extra code complexity) of making the class testable in this way. (The fact that there is a static method at the bottom of this is a large part of the problem.)
How to unit test C # with xUnit?
Here’s how we’ll do it with xUnit. First, we decorated the test method with [Fact]. [Fact], as I mentioned in my previous article on unit testing C#/.NET code with xUnit, is used to tell the test runner to actually run the test. If the test runner completes the test without throwing an exception or failing an Assert, the test passes.