[New job] 🐘 Gradle test with jUnit

## Objective

This job allows you to run the unit tests of 🐘 Gradle project.

You can easily have a badge configure on your 🦊 Gitlab project with this regex `([0-9]{1,3}.[0-9]*).%.covered` configured in `settings/ci_cd` section. See galery for example.

## How to use it

1. Ensure that your project have

   [`build.gradle.kts`](https://docs.gradle.org/current/samples/sample_building_java_applications.html){:target="_blank"} 

   file

1. Add this job URL inside the `include` list of your `.gitlab-ci.yml` file (see the [quick setup](/use-the-hub/#quick-setup)). You can specify [a fixed version](#changelog) instead of `latest`.

    ```yaml

      - remote: 'https://jobs.r2devops.io/latest/gradle_test.yml'

    ```

1. Well done, your job is ready to work ! 😀

🔗 Here is an example of a complete pipeline using this step : [fun_with_gitlab-ci](https://gitlab.com/fun_with/fun-with-gitlab-ci/-/blob/master/.gitlab-ci.yml)

## Job details

* Job name: `gradle_test`

* Default stage: `static_tests`

* Docker image: [`gradle:jdk11`](https://hub.docker.com/_/gradle){:target="_blank"}

* When: `always`

### Variables

| Name | Description | Default |

| ---- | ----------- | ------- |

| JACOCO_CSV_LOCATION | Path to CSV file containing report | ${CI_PROJECT_DIR}/reports/jacoco/csv/jacoco.csv |

| JACOCO_HTML_LOCATION | Folder containing report as a HTML website | ${CI_PROJECT_DIR}/reports/jacoco/html |

| JACOCO_XML_LOCATION | Folder containing report as XML file | ${CI_PROJECT_DIR}/reports/jacoco/xml |

⚠️ These paths are defined within `build.gradle` file.

### Example of build.gradle.kts file

Following example of `build.gradle.kts` file describes a very simple example of project configuration.

This can easily be generated with the `gradle init` command.

***For a Java project***

```kotlin

import org.gradle.api.JavaVersion.VERSION_11

plugins {

    java

    // Analyze coverage

    jacoco

}

group = "io.r2devops"

version = "1.0.0-SNAPSHOT"

java.sourceCompatibility = VERSION_11

java.targetCompatibility = VERSION_11

repositories {

    jcenter()

    mavenCentral()

}

dependencies {

    // Use JUnit Jupiter API for testing.

    testImplementation("org.junit.jupiter:junit-jupiter-api:5.6.2")

    // Use JUnit Jupiter Engine for testing.

    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.6.2")

}

tasks.test {

    // Report is always generated after tests run

    finalizedBy(tasks.jacocoTestReport)

    // Use junit platform for unit tests

    useJUnitPlatform()

}

tasks.jacocoTestReport {

    // Tests are required to run before generating the report

    dependsOn(tasks.test)

    // Enable CSV for badge on project

    csv.isEnabled = true

    csv.destination = file("${buildDir}/reports/jacoco/csv/jacoco.csv")

    // Enable XML to convert to cobertura format for MR display

    xml.isEnabled = true

    xml.destination = file("${buildDir}/reports/jacoco/xml/jacoco.xml")

    // Enable HTML to publish on Pages

    html.destination = file("${buildDir}/reports/jacoco/html")    

}

```

***For a Kotlin project***

```kotlin

import org.gradle.api.JavaVersion.VERSION_11

plugins {

    id("org.jetbrains.kotlin.jvm") version "1.4.21"

    // Analyze coverage

    jacoco

}

group = "io.r2devops"

version = "1.0.0-SNAPSHOT"

java.sourceCompatibility = VERSION_11

java.targetCompatibility = VERSION_11

kotlin.target { VERSION_11 }

repositories {

    jcenter()

    mavenCentral()

}

dependencies {

    // Align versions of all Kotlin components

    implementation(platform("org.jetbrains.kotlin:kotlin-bom"))

    // Use the Kotlin JDK 8 standard library.

    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")

    // Use the Kotlin test library.

    testImplementation("org.jetbrains.kotlin:kotlin-test")

    // Use the Kotlin JUnit integration.

    testImplementation("org.jetbrains.kotlin:kotlin-test-junit")

}

tasks.test {

    finalizedBy(tasks.jacocoTestReport) // report is always generated after tests run

}

tasks.jacocoTestReport {

    dependsOn(tasks.test) // tests are required to run before generating the report

    // Enable CSV for badge on project

    csv.isEnabled = true

    csv.destination = file("${buildDir}/reports/jacoco/csv/jacoco.csv")

    // Enable XML to convert to cobertura format for MR display

    xml.isEnabled = true

    xml.destination = file("${buildDir}/reports/jacoco/xml/jacoco.xml")

    // Enable HTML to publish on Pages

    html.destination = file("${buildDir}/reports/jacoco/html")

}

```

### Example to deploy HTML report to pages

```yaml

stages:

  - static_tests

  - deploy

include:

  - remote: 'https://jobs.r2devops.io/gradle_test.yml'

# Test deployment to Gitlab pages

pages:

  stage: deploy

  image: alpine:latest

  script:

    - mkdir public

    - mv $JACOCO_HTML_LOCATION public

  needs:

    - job: gradle_test

      artifacts: true

  cache: {}

  artifacts:

    paths:

      - public

```

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stages:

  - static_tests

# Run unit tests

gradle_test:

  stage: static_tests

  image: gradle:jdk11

  script:

    - gradle check

    - awk -F"," '{ instructions += $4 + $5; covered += $5 } END { print covered, "/", instructions, " instructions covered"; print 100*covered/instructions, "% covered" }' $JACOCO_CSV_LOCATION

  variables:

    JACOCO_CSV_LOCATION: '$CI_PROJECT_DIR/build/reports/jacoco/csv/jacoco.csv'

    JACOCO_HTML_LOCATION: '$CI_PROJECT_DIR/build/reports/jacoco/html'

    JACOCO_XML_LOCATION: '$CI_PROJECT_DIR/build/reports/jacoco/xml'

  cache:

    key: "$CI_COMMIT_REF_NAME"

    policy: pull

    paths:

      - build

      - .gradle

  artifacts:

    paths:

      - $JACOCO_CSV_LOCATION

      - $JACOCO_HTML_LOCATION

      - $JACOCO_XML_LOCATION

    reports:

      junit: 

        - "${JACOCO_XML_LOCATION}/surefire-reports/TEST-*.xml"

  coverage: '/^([0-9]{1,3}.[0-9]*).%.covered$/'

name: gradle_test

description: Run your unit tests with 🐘 Gradle & jUnit

default_stage: static_tests

icon: 🐘

maintainer: yodamad

license: MIT

images:

  "gradle": "jdk11"

tools:

  "Gradle": "$GRADLE_VERSION"

labels:

    - GitLab

    - Gradle

    - Test

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