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From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.java.programmer
Subject: How to test my @NotEmpty with JUnit
Date: Fri, 17 Jul 2015 10:36:33 +0200
Organization: Decebal Computing
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We have to remove almost every framework used in the code. I started
with the @NotEmpty from Hibernate. It was the only class used from
Hibernate, so low hanging fruit we thought.

I wrote the following implementation:

    import        java.lang.annotation.Documented;
    import static java.lang.annotation.ElementType.FIELD;
    import        java.lang.annotation.Retention;
    import static java.lang.annotation.RetentionPolicy.RUNTIME;
    import        java.lang.annotation.Target;

    import        javax.validation.Constraint;
    import        javax.validation.constraints.NotNull;
    import        javax.validation.constraints.Size;
    import        javax.validation.ReportAsSingleViolation;

    @Documented
    @Constraint(validatedBy = {})
    @Target({ FIELD })
    @Retention(RUNTIME)
    @ReportAsSingleViolation
    @NotNull
    @Size(min = 1)
    public @interface NotEmpty {
        public abstract String message() default "Field has to be filled";
    }


But it should be tested also of-course. So I wrote the following test:

    import org.junit.Test;

    class NotEmptyClass {
        @NotEmpty
        String notEmpty;

        NotEmptyClass(String value) {
            notEmpty = value;
        }
    }

    public class NotEmptyTest {
        @Test
        public void firstTest() {
            new NotEmptyClass(null);
        }
    }

I would expect this test not to pass, but it does. So clearly I am
doing something wrong, but I have no idea what. (This is the first
time I really work with annotations.) I did some Googling but until
now to no avail. So if someone could point me to the right direction …

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof