Gradle Goodness: Show Standard Out or Error Output from Tests
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Join For FreeWe use the Test
task in Gradle to run tests. If we use the System.out.println
or System.err.println
methods in our test we don't see the output when we execute the tests. We can customize the test task to show any output send to standard out or error in the Gradle output.
First we show our test class written with Spock, but it could also be a JUnit or TestNG test:
// File: src/test/groovy/com/mrhaki/gradle/SampleSpec.groovy package com.mrhaki.gradle import spock.lang.* class SampleSpec extends Specification { def "check that Gradle is Gr8"() { when: def value = 'Gradle is great!' then: // Include a println statement, so // we have output to show. println "Value = [$value]" value == 'Gradle is great!' } }
Now we write a simple Gradle build file which can execute our test:
// File: build.gradle apply plugin: 'groovy' // Adds test task repositories.jcenter() dependencies { compile 'org.codehaus.groovy:groovy-all:2.3.7' testCompile 'org.spockframework:spock-core:0.7-groovy-2.0' }
Let's run the test
task from the command line and look at the output:
$ gradle test :compileJava UP-TO-DATE :compileGroovy UP-TO-DATE :processResources UP-TO-DATE :classes UP-TO-DATE :compileTestJava :compileTestGroovy :processTestResources UP-TO-DATE :testClasses :test BUILD SUCCESSFUL Total time: 7.022 secs $
Well at least our test is successful, but we don't see the output of our println
method invocation in the test. We customize the test
task and add thetestLogging
method with a configuration closure. In the closure we set the property showStandardStreams
to the value true
. Alternatively we can set the events
property or use the events
method with the values standard_out
and standard_err
to achieve the same result. In the next build file we use the showStandardStreams
property:
00.
// File: build.gradle
01.
apply plugin:
'groovy'
// Adds test task
02.
03.
repositories.jcenter()
04.
05.
dependencies {
06.
compile
'org.codehaus.groovy:groovy-all:2.3.7'
07.
testCompile
'org.spockframework:spock-core:0.7-groovy-2.0'
08.
}
09.
10.
test {
11.
testLogging {
12.
// Make sure output from
13.
// standard out or error is shown
14.
// in Gradle output.
15.
showStandardStreams = true
16.
17.
// Or we use events method:
18.
// events 'standard_out', 'standard_error'
19.
20.
// Or set property events:
21.
// events = ['standard_out', 'standard_error']
22.
23.
// Instead of string values we can
24.
// use enum values:
25.
// events org.gradle.api.tasks.testing.logging.TestLogEvent.STANDARD_OUT,
26.
// org.gradle.api.tasks.testing.logging.TestLogEvent.STANDARD_ERROR,
27.
}
28.
}
We re-run the test
task from the command line and look at the output to see the result from the println
method:
$ gradle test
:compileJava UP-TO-DATE
:compileGroovy UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:compileTestJava
:compileTestGroovy
:processTestResources UP-TO-DATE
:testClasses
:test
com.mrhaki.gradle.SampleSpec > check that Gradle is Gr8 STANDARD_OUT
Value = [Gradle is great!]
BUILD SUCCESSFUL
Total time: 8.716 secs
$
Written with Gradle 2.1.
Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.
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