support for assertEmpty

[Barbatruuk]

Hello,

Sorry if this has been requested/discussed before, I didn't find a reference to a similar request.

I'd like to have an assertEmpty(...) method that tests for instance if a String is empty. I understand that:
assertEquals("", someString);
assertTrue(someString.isEmpty());

have similar effect, but it reads so much easier:
assertEmpty(someString);

any thoughts on that?

Thanks,

[djh82]

You would normally write:

import org.junit.Test;
import static org.junit.Assert.*;
import static org.hamcrest.text.IsEmptyString.*;

public class EmptyStringTest
{
    @Test
    public void test()
    {
        assertThat("", isEmptyString());
    }
}

[djh82]

If that solves your problem, can you close the issue?

Thanks for your contribution, hopefully it will help someone else too :)

[Barbatruuk]

Yes and No ;)

I'm using JUnit 4.10 (via maven) which has a dependency to hamcrest-core 1.1, the core version does not have the text package included. There is however, a hamcrest-text 1.1 that does have this package, but not the IsEmptyString class (and it's not in maven). I like to keep version synchronised but it looks like that's not possible in thise case. I can however include hamcrest-all 1.3 and exclude hamcrest-core 1.1 from JUnit (perhaps you could rollout a JUnit version that uses 1.3? :) ).

But wait...

running assertThat("", isEmptyString()); throws a:

    java.lang.NoSuchMethodError: org.hamcrest.core.AnyOf.anyOf([Lorg/hamcrest/Matcher;)Lorg/hamcrest/core/AnyOf;
    at org.hamcrest.text.IsEmptyString.<clinit>(IsEmptyString.java:18)    

because of (copy & paste from decompiled class, excuse the capitalization):

private static final Matcher<String> NULL_OR_EMPTY_INSTANCE = AnyOf.anyOf(new Matcher[] { IsNull.nullValue(), INSTANCE });

which is inside the IsEmptyString class

So, there appears to be an issue in the hamcrest IsEmptyString class, but quite honestly I don't understand what's supposed to happen inside the AnyOf class, perhaps you do?

Guess I have to stick to my old trick.

[djh82]

You're right, I do apologise. That's what you would need to write if Hamcrest 1.3 was supported ;) See #404.

The AnyOf class allows you to specify an array (vararg) of matchers; the result will be true if 'any of' the matchers return true. The IsEmptyString use of AnyOf is to combine a null matcher with an empty string matcher to create a nullOrEmptyString matcher.

[dsaff]

Right, this should be better once we get #404 submitted.

[Barbatruuk]

Closed hoping the next release will have #404 fixed this.