Gradle Test Logger Plugin

A Gradle plugin for printing beautiful logs on the console while running tests.

Screenshots

Standard theme

Mocha theme

Scroll down for more themes and customisation options or visit the screenshots page for more demos.

Usage

Using the plugins DSL

plugins {
    id 'com.adarshr.test-logger' version '4.0.0'
}

Using legacy plugin application

buildscript {
    repositories {
        maven {
            url 'https://plugins.gradle.org/m2/'
        }
    }
    dependencies {
        classpath 'com.adarshr:gradle-test-logger-plugin:4.0.0'
    }
}

apply plugin: 'com.adarshr.test-logger'

Compatibility matrix

Configuration

The plugin registers an extension called testlogger (all lowercase and one word) at project level as well as for each task of type Test.

The following shows the complete default configuration applied when you configure nothing.

testlogger {
    theme 'standard'
    showExceptions true
    showStackTraces true
    showFullStackTraces false
    showCauses true
    slowThreshold 2000
    showSummary true
    showSimpleNames false
    showPassed true
    showSkipped true
    showFailed true
    showOnlySlow false
    showStandardStreams false
    showPassedStandardStreams true
    showSkippedStandardStreams true
    showFailedStandardStreams true
    logLevel 'lifecycle'
}

Project vs task level configuration

Settings configured at the project level can be overridden by redefining them at task level. Settings not defined at task level will inherit project level values. Consider the below configuration.

testlogger {
    theme 'mocha' // project level
    slowThreshold 5000
}

test {
    testlogger {
        theme 'standard-parallel' // task level
    }
}

In the above example, the effective theme will be standard-parallel and slowThreshold will be 5000 whereas rest of the settings will retain their default values.

Overriding settings at runtime

All the above settings can either be specified in build.gradle or be set at runtime using system properties or both. For instance, we could have theme set to mocha in the build file but it can be overridden to be standard at runtime by using -Dtestlogger.theme=standard on the command line. Since they are system properties we have a number of ways of specifying them including JAVA_OPTS and gradle.properties.

• The convention used for determining the name of the system property is testlogger.<configuration setting>.
• System property overrides will be applied after combining task and project level settings.
• Specifying a system property override will apply the same setting for all tasks, regardless of any configuration defined in the build file.

Switch themes

testlogger {
    theme 'mocha'
}

The following themes are currently supported:

1. plain - displays no colours or Unicode symbols
2. standard - displays colours but no Unicode symbols
3. mocha - similar to what Mocha's spec reporter prints, with colours and Unicode symbols
4. plain-parallel - similar to the plain theme but supports parallel test execution
5. standard-parallel - similar to the standard theme but supports parallel test execution
6. mocha-parallel - similar to the mocha theme but supports parallel test execution

Hide exceptions

By default, the showExceptions flag is turned on. This shows why the tests failed including the location of the failure. Of course, you can switch off this slightly more verbose logging by setting showExceptions to false.

testlogger {
    showExceptions false
}

Hide exception stack traces

Sometimes it is useful to just see the exception message instead of the stack trace. This can be configured by setting showStackTraces to false.

testlogger {
    showStackTraces false
}

Hide exception causes

The default behaviour of the plugin is to print all the causes of the exception. If it is too verbose to your taste, you can turn it off by setting showCauses to false.

testlogger {
    showCauses false
}

Show full exception stack traces

Just like Gradle itself, by default only the last frame that matches the test class's name in a stack trace is printed. For vast majority of cases, that is sufficient. Sometimes, it is useful to remove this filtering in order to see the entirety of the stack trace. This can be done by setting showFullStackTraces to true.

testlogger {
    showFullStackTraces true
}

Define slow threshold

Tests that are too slow will have their duration logged. However, "slow" is a relative terminology varying widely depending on the type of tests being executed, environment, kind of project and various other factors. Therefore you can define what you consider as slow to suit your needs.

testlogger {
    slowThreshold 5000
}

The default value of slowThreshold is 2 seconds. So all tests that take longer than a second to run will have their actual execution time logged.

If you want to turn off the logging of time taken completely, simply set the threshold to a very large value.

Please note that in themes that support colours, the duration is displayed using a warning style if it is greater than half the slow threshold. For instance, if slowThreshold is 5 seconds any tests that take longer than 2.5 seconds to run would have their durations logged using a warning style and those that take longer than 5 seconds to run using an error style.

Hide summary

By default, a useful summary containing a breakdown of passing, failing and skipped tests along with the total time taken to execute all the tests is shown. Of course, you can disable this if you prefer a more succinct output.

testlogger {
    showSummary false
}

Show simple names

If you don't like seeing long, fully-qualified class names being used for displaying the test suite names, you can choose to show only simple names by setting the below flag to true.

testlogger {
    showSimpleNames true
}

Show standard streams

The display of standard output and error streams alongside the test logs can be controlled using the below configuration.

testlogger {
    showStandardStreams true
}

Filter standard streams

If the display standard output and error streams is enabled, it can often produce too much output to overwhelm anyone. Fortunately, we can filter this output based on the type of the test result.

testlogger {
    showStandardStreams true
    showPassedStandardStreams false
    showSkippedStandardStreams false
    showFailedStandardStreams true
}

All the three filter flags are enabled by default. In other words, the standard stream output is not filtered if showStandardStreams is enabled but none of the filter flags are configured.

If showStandardStreams is set to false, the filter flags don't have any effect.

Filter test results

Sometimes it is useful to hide test results of a certain type. For instance, if an application has hundreds of tests, the sheer volume of the output produced by passing tests could be enough to bury any valuable test failures. Similarly there might be a need to hide skipped tests or in rare instances even the failed ones.

We can perform test result filtering by using the below settings.

testlogger {
    showPassed false
    showSkipped false
    showFailed true
    showOnlySlow false
}

By default the flags showPassed, showSkipped and showFailed are turned on while showOnlySlow will be off. If you have chosen to display standard streams by setting showStandardStreams flag to true, any output produced by filtered out tests will not be displayed.

Change log level

By default, results are output at the standard lifecycle Gradle log level. This can be configured with logLevel. For example, the following will output the results even on runs with --quiet.

testlogger {
    logLevel 'quiet'
}

Relationship between testlogger and Test.testLogging

Where possible, the plugin's testlogger extension tries to react to equivalent properties of Gradle's Test.testLogging extension. However, if a value is explicitly configured under the testlogger extension, the plugin does not react to the corresponding property of Test.testLogging. The below table demonstrates this in more detail.

In other words, an explicitly configured testlogger property, despite it being false, takes precedence over any value of Test.testLogging.

Kotlin DSL

If you are using the Kotlin DSL, the syntax of testlogger extension DSL changes slightly. The following shows the default configuration properties using Kotlin DSL style.

testlogger {
    theme = ThemeType.STANDARD
    showExceptions = true
    showStackTraces = true
    showFullStackTraces = false
    showCauses = true
    slowThreshold = 2000
    showSummary = true
    showSimpleNames = false
    showPassed = true
    showSkipped = true
    showFailed = true
    showOnlySlow = false
    showStandardStreams = false
    showPassedStandardStreams = true
    showSkippedStandardStreams = true
    showFailedStandardStreams = true
    logLevel = LogLevel.LIFECYCLE
}

One gotcha about Kotlin DSL is that if you have subprojects that are trying to use a different testlogger setting compared to the parent project, the syntax changes slightly.

subprojects {

    apply {
        plugin("com.adarshr.test-logger")
    }

    configure<TestLoggerExtension> {
        theme = ThemeType.STANDARD
        showExceptions = true
        ...
    }
}

FAQ

Does it work on Windows?

Mostly. The standard and plain themes work out of the box but you might have to make a few modifications to your system settings to see Unicode symbols when using the mocha theme.

1. Set or update JAVA_OPTS with the system property -Dfile.encoding=UTF-8
2. Change the terminal code page to 65001 by executing chcp 65001

How to disable colours and Unicode symbols at runtime such as on Jenkins consoles?

You can switch off ANSI control characters and Unicode symbols by adding --console=plain to your Gradle command line.

Does it support parallel test execution?

Yes. You will need to switch to a suitable parallel theme though. This can be one of plain-parallel, standard-parallel or mocha-parallel. The parallel themes are specially designed to work with a setting of maxParallelForks greater than 1. They achieve this by sacrificing the ability to group tests and thus some readability is lost.

Can this plugin co-exist with junit-platform-gradle-plugin?

Due to certain unknown reasons, junit-platform-gradle-plugin is incompatible with gradle-test-logger-plugin. If you are still using junit-platform-gradle-plugin, it might be worth noting that this plugin was deprecated in JUnit Platform 1.2 and removed from JUnit Platform 1.3.

The test logger plugin however, is fully compatible with the Gradle native way of using JUnit 5.

I see the test output twice. How can I fix it?

Example:

> Task :myTest
org.project.MyTest
  Test test() FAILED
  org.opentest4j.AssertionFailedError: expected: <Optional[String]> but was: <Optional.empty>

MyTest > test() FAILED
    org.opentest4j.AssertionFailedError: expected: <Optional[String]> but was: <Optional.empty>
        at app//org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)

Then, you still have testLogging of gradle enabled. Example setting:

  testLogging {
    events = ["FAILED"]
    exceptionFormat "full"
  }

Solution: Remove that setting from your build.gradle.