lachlanmckee / timber-junit-rule

A highly configurable JUnit Rule that outputs Timber logs to standard output

Timber JUnit-Rule

This library provides a JUnit TestRule that plants a temporary Timber tree that pipes any logs sent via Timber to the standard System.out. Once a unit test has completed, the Timber tree is removed to avoid logging unintended test cases.

The rule is extremely useful for Android JUnit tests, as the Timber logs do not show without planting a tree.

Usage

Using the library is very straight forward. An example is as follows:

public class TestExample {
    @Rule
    public TimberTestRule timberTestRule = TimberTestRule.builder()
            .minPriority(Log.ERROR)
            .showThread(true)
            .showTimestamp(false)
            .onlyLogWhenTestFails(true)
            .build();
}

There are also several factory methods which cover many common cases. These are:

public class TestExample {
    @Rule
    public TimberTestRule logAllAlwaysRule = TimberTestRule.logAllAlways();
    @Rule
    public TimberTestRule logAllOnFailuresRule = TimberTestRule.logAllWhenTestFails();
    @Rule
    public TimberTestRule logErrorsAlwaysRule = TimberTestRule.logErrorsAlways();
    @Rule
    public TimberTestRule logErrorsOnFailuresRule = TimberTestRule.logErrorsWhenTestFails();
}

Configuration

As seen in the example above, there are many ways to modify the output using the following behaviours:

• The minimum log level to output.
• Whether thread ids are shown.
• Whether timestamps are shown.
• Whether to always log, or only log when a unit test fails.

Download

This library is available on Maven, you can add it to your project using the following gradle dependencies:

testCompile 'net.lachlanmckee:timber-junit-rule:1.0.1'

timber-junit-rule's Issues

Concurrency issue with flush

There appears to be a race condition in BufferedJUnitTimberTree.flushLogs. If mLogMessageBuffer is mutated by another thread while flushLogs is running, a ConcurrentModificationException is thrown.

Unfortunately I don't have a precise example to repro but the defect seems straight forward and should be quite easy to fix by adding some synchronization.

Cheers!

Support for JUnit 5?

Hi @LachlanMcKee ,

Thanks for this library, I had it in use on multiple apps.
Now with migrating to Junit 5 we need an other approach with a Junit 5 extension.
Are you planning to implement that in this library?

A Guide to JUnit 5 Extensions

Cheers

Add a feature to only log when a unit test fails

Currently the Timber JUnit rule will log for every single test, regardless of the outcome of the test.

This can be quite noisy, and unnecessary when unit tests are passing.

The enhancement to add will be to add a feature that buffer the logs and only outputs them if the unit test fails.

Update project to latest stable Android Studio

To further develop this project it must be brought up to date with the latest Android Studio tooling.