Will an assertion error be caught by in a catch block for java exception?

java junit try-catch assert
Galet picture Galet · Apr 16, 2015 · Viewed 45.9k times · Source

Code:-

try {
    Assert.assertEquals("1", "2");
} catch (Exception e) {
    System.out.println("I am in error block");
}

If the assert statements fails, I would like to capture the error in the catch block. I am trying with the above code and its not happening.

Will the assertion error be caught by in a catch block for java exception?

Answer

J Richard Snape picture J Richard Snape · Apr 16, 2015

You have almost answered your own question. Your catch block will not catch the AssertionError that the Assert throws if it fails, because it is an Error (or, more specifically, it extends java.lang.Error). See the docs for more information on this. Your catch block only catches Throwable objects that extend java.lang.Exception

If you really want to catch it - you need to use

catch (AssertionError e) {
...

However, as others have mentioned, this is a very unusual way to use assertions - they should usually pass and if they fail it is very unusual for you to want to carry on program execution. That's why the failure throws an Error rather than an Exception. You can read more about (not) catching Error in this question.

Are you sure you don't just want a test - if ( variableName == "1")?

NB if you are testing unit-test helper code, like a matcher, it might make sense to catch the AssertionError.

Related questions

Try catch in a JUnit test

I'm writing unit tests for an application that already exists for a long time. Some of the methods I need to test are build like this: public void someMethod() throws Exception { //do something } If I want to test these methods …

Read More
How do you assert that a certain exception is thrown in JUnit 4 tests?

How can I use JUnit4 idiomatically to test that some code throws an exception? While I can certainly do something like this: @Test public void testFooThrowsIndexOutOfBoundsException() { boolean thrown = false; try { foo.doStuff(); } catch (IndexOutOfBoundsException e) { thrown = true; } assertTrue(thrown); } I …

Read More
Mockito : how to verify method was called on an object created within a method?

I am new to Mockito. Given the class below, how can I use Mockito to verify that someMethod was invoked exactly once after foo was invoked? public class Foo { public void foo(){ Bar bar = new Bar(); bar.someMethod(); } } I would …

Read More