strange AssertError when using fest regexp assert

Question

I am getting this error - but the regex should imho match the string - would love to know what is the problem here

java.lang.AssertionError: <'0 I: bar
1 I: foo
'> should match the regular expression:<'.*bar.*'>
    at org.fest.assertions.Fail.failure(Fail.java:228)
    at org.fest.assertions.Assert.failure(Assert.java:149)
    at org.fest.assertions.StringAssert.matches(StringAssert.java:129)
    at org.ligi.tracedroid.test.TheLog.should_rotate_proper(TheLog.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:241)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:177)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:80)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:47)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:69)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:49)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
    at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
    at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:103)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:355)
    at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:66)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:724)

this is the test causing the problem ( boiled down ):

package org.ligi.tracedroid.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.ligi.tracedroid.logging.Log;

import static org.fest.assertions.Assertions.assertThat;
@RunWith(Runner.class)
public class TheLog {

    @Test
    public void should_rotate_proper() {
        Log.setLogCacheSize(2);
        Log.i("forget me");
        Log.i("foo");
        Log.i("bar");

        // TODO investigate why this is not working
        assertThat(Log.getCachedLog()).matches(".*bar.*");
    }

}

Answer 1

. does not match newline unless you specify Pattern.DOTALL flag or (?s) inside the pattern.

Change as follow:

assertThat(Log.getCachedLog()).matches("(?s).*bar.*");

But if you want just check bar is contained in the log, contains seems more appropriate:

assertThat(Log.getCachedLog()).contains("bar");