Lidalia Test -

Lidalia Test

Some utility Hamcrest matchers, a means to test exception behaviour more robustly than JUnit provides by default and JUnit rules for common testing scenarios.

See the JavaDocs for full documentation and the Test Source for complete examples of usage. Below are some examples from some of the more common classes.

Details on how to depend on this library in your favourite build tool can be found here.

Examples

Testing a time sensitive bit of code

import org.joda.time.Instant;
import org.junit.Rule;
import org.junit.Test;
import uk.org.lidalia.test.StaticTimeRule;

import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;
import static uk.org.lidalia.test.StaticTimeRule.alwaysNow;

public class StaticTimeTest {

    @Rule public StaticTimeRule nowStaticTime = alwaysNow();

    @Test
    public void nowStaticTimeKeepsTimeStatic() {
        assertThat(new Instant(), is(nowStaticTime.getInstant()));
    }
}

Testing code that writes to System.out

import org.junit.Rule;
import org.junit.Test;
import uk.org.lidalia.test.SystemOutputRule;

import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;

public class SystemOutputTest {

    @Rule public SystemOutputRule systemOutputRule = new SystemOutputRule();

    @Test
    public void useSysOut() {
        System.out.print("some text");
        assertThat(systemOutputRule.getSystemOut(), is("some text"));
    }
}

Asserting details about a thrown exception

import org.junit.Test;

import uk.org.lidalia.lang.Task;

import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;
import static uk.org.lidalia.test.ShouldThrow.shouldThrow;

public class ShouldThrowTest {

    @Test
    public void throwsExpectedException() {
        RuntimeException exceptionThrown = shouldThrow(RuntimeException.class, new Task() {
            @Override
            public void perform() {
                final Exception cause = new Exception("cause exception message");
                throw new RuntimeException("exception message", cause);
            }
        });
        assertThat(exceptionThrown.getMessage(), is("exception message"));
        assertThat(exceptionThrown.getCause().getMessage(), is("cause exception message"));
    }
}

Checking a static utility method class is not instantiable

The primary value in this is to keep code coverage tools happy which may not be such a great aim anyway. Still, if someone has foisted them on you this allows you to test this edge case with a genuine assertion and no further pain.

public class MyStaticMethods {
    ... lots of static methods ...

    private MyStaticMethods() {
        throw new UnsupportedOperationException("Not instantiable");
    }
}

import org.junit.Test;
import static org.junit.Assert.assertThat;
import static uk.org.lidalia.test.Assert.isNotInstantiable;

public class MyStaticMethodsTest {
    @Test
    public void notInstantiable() {
        assertThat(MyStaticMethods.class, isNotInstantiable());
    }
}