test: update and document java requirements for gradle

.github/workflows/test.yml

@@ -24,6 +24,7 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
         node-version: [10, 12]
         python-version: [3.8]
+        java-version: [11]
         exclude:
           - os: windows-latest
             node-version: 10
@@ -39,14 +40,14 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
-      - name: Set up Java 11
-        if: matrix.os == 'ubuntu-latest' && matrix.node-version == 12 && github.ref != 'refs/heads/master'
+      - name: Set up Java ${{ matrix.java-version }}
+        if: matrix.node-version == 12 && github.ref != 'refs/heads/master'
         uses: actions/setup-java@v1
         with:
-          java-version: 11
+          java-version: ${{ matrix.java-version }}
 
       - name: Skip Java tests
-        if: matrix.os != 'ubuntu-latest' || matrix.node-version != 12 || github.ref == 'refs/heads/master'
+        if: matrix.node-version != 12 || github.ref == 'refs/heads/master'
         run: echo "::set-env name=SKIP_JAVA_TESTS::true"
 
       - name: Init platform

docs/development/local-development.md

@@ -15,16 +15,20 @@ and `exports`. We will transpile them to `commonjs` on build.
 
 #### Prerequisites
 
-For local development some dependencies are required.
+For local development some dependencies are required:
 
 - git
 - nodejs `^10.13.0 || ^12.0.0`
 - yarn `^1.17.0`
 - c++ compiler
 - python `^2.7` with `mock` library
+- java between `8` and `12`
 
 Python 2.7 is required in development in order to support installing with `node-gyp`, which does not yet support Python 3. `mock` is used by Renovate in production and is now part of the Python standard library, but only from 3.3 onwards.
 
+Java is required to execute Gradle in tests.
+If you don’t have Java installed, the respective tests will be skipped.
+
 _Linux_
 
 You can use the following commands for `Ubuntu`.
@@ -34,9 +38,11 @@ curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
 curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
 echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
 sudo apt-get update
-sudo apt-get install -y git python-minimal build-essential nodejs yarn
+sudo apt-get install -y git python-minimal build-essential nodejs yarn default-jre-headless
 ```
 
+You can also use [SDKMAN](https://sdkman.io/) to manage Java versions.
+
 _Windows_
 
 The following steps work to set up a brand new Windows 10 installation for developing Renovate. If you already have some components installed, you can naturally skip them.
@@ -46,11 +52,11 @@ The following steps work to set up a brand new Windows 10 installation for devel
 - In an Administrator PowerShell prompt, run `npm install -global npm` and then `npm --add-python-to-path='true' --debug install --global windows-build-tools`
 - Install [Yarn](https://yarnpkg.com/lang/en/docs/install/#windows-stable)
 - Install `mock` for Python:
-
   - `curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py`
   - `python get-pip.py`
   - `rm get-pip.py`
   - `python -m pip install mock`
+- Install Java, e.g. from [AdoptOpenJDK](https://adoptopenjdk.net/?variant=openjdk11) or any other distribution
 
   Verify you have everything installed with appropriate versions, e.g.:
 
@@ -65,6 +71,10 @@ The following steps work to set up a brand new Windows 10 installation for devel
   Python 2.7.16
   PS C:\Windows\system32> python -c "import mock; print(mock.__version__)"
   3.0.5
+  PS C:\Windows\system32> java -version
+  openjdk version "11.0.6" 2020-01-14
+  OpenJDK Runtime Environment 18.9 (build 11.0.6+10)
+  OpenJDK 64-Bit Server VM 18.9 (build 11.0.6+10, mixed mode)
   ```
 
 #### Fork and Clone

lib/manager/gradle/gradle-updates-report.spec.ts

@@ -1,6 +1,7 @@
 import tmp, { DirectoryResult } from 'tmp-promise';
 import * as fs from 'fs-extra';
 import * as path from 'path';
+import { spawnSync, SpawnSyncReturns } from 'child_process';
 import { exec } from '../../util/exec';
 import { GRADLE_DEPENDENCY_REPORT_OPTIONS } from './index';
 import {
@@ -9,75 +10,95 @@ import {
 } from './gradle-updates-report';
 
 const fixtures = 'lib/manager/gradle/__fixtures__';
-const skipJavaTestsEnv = 'SKIP_JAVA_TESTS';
+const failIfNoJavaEnv = 'CI';
 
 const gradleJavaVersionSupport = {
   5: { min: 8, max: 12 },
   6: { min: 8, max: 13 },
 };
 
+const skipJava = process.env.SKIP_JAVA_TESTS === 'true';
+const enforceJava = process.env[failIfNoJavaEnv] === 'true' && !skipJava;
+
 function parseJavaVersion(javaVersionOutput: string) {
   const versionMatch = /version "(?:1\.)?(\d+)[\d._-]*"/.exec(
     javaVersionOutput
   );
   if (versionMatch !== null && versionMatch.length === 2) {
     return parseInt(versionMatch[1], 10);
   }
+  if (enforceJava)
+    throw Error(`This test suite needs Java and ${failIfNoJavaEnv} is set. However, we cannot parse the Java version.
+The output of java -version was:
+${javaVersionOutput}`);
   return 0;
 }
 
+function determineJavaVersion(): number {
+  let javaVersionCommand: SpawnSyncReturns<string>;
+  let error: Error;
+  try {
+    javaVersionCommand = spawnSync('java', ['-version'], {
+      encoding: 'utf8',
+      windowsHide: true,
+    });
+  } catch (e) {
+    error = e;
+  }
+  if (javaVersionCommand.error) error = javaVersionCommand.error;
+  if (error) {
+    if (!enforceJava) return 0;
+    throw Error(
+      `This test suite needs Java and ${failIfNoJavaEnv} is set.
+Result of java -version:
+${error}`
+    );
+  }
+  return parseJavaVersion(javaVersionCommand.stderr);
+}
+
 describe('lib/manager/gradle/gradle-updates-report', () => {
   let workingDir: DirectoryResult;
-  let javaVersion: number;
-  const skipJava = process.env[skipJavaTestsEnv] !== undefined;
-
-  beforeAll(async () => {
-    javaVersion = await exec('java -version')
-      .then(({ stderr }) => parseJavaVersion(stderr))
-      .catch(reason => {
-        throw Error(
-          `This test suite needs Java. Please provide Java or set the environment variable ${skipJavaTestsEnv} to true.
-Output of java -version:
-${reason}`
-        );
-      });
-  });
+  const javaVersion = determineJavaVersion();
 
   beforeEach(async () => {
     workingDir = await tmp.dir({ unsafeCleanup: true });
   });
 
   describe('createRenovateGradlePlugin', () => {
-    (skipJava ? it.skip : it).each([[5], [6]])(
-      `generates a report for Gradle version %i`,
-      async (gradleVersion: number) => {
-        const supportedJavaVersions = gradleJavaVersionSupport[gradleVersion];
-        if (
-          javaVersion < supportedJavaVersions.min ||
-          javaVersion > supportedJavaVersions.max
-        ) {
-          throw Error(
-            `This test needs a Java version between ${supportedJavaVersions.min} and ${supportedJavaVersions.max}`
-          );
-        }
-        await fs.copy(`${fixtures}/minimal-project`, workingDir.path);
-        await fs.copy(
-          `${fixtures}/gradle-wrappers/${gradleVersion}`,
-          workingDir.path
+    for (const gradleVersion of [5, 6]) {
+      const supportedJavaVersions = gradleJavaVersionSupport[gradleVersion];
+      const gradleSupportsThisJavaVersion =
+        javaVersion >= supportedJavaVersions.min &&
+        javaVersion <= supportedJavaVersions.max;
+      if (!gradleSupportsThisJavaVersion && enforceJava)
+        throw Error(
+          `This test needs a Java version between ${supportedJavaVersions.min} and ${supportedJavaVersions.max}. The current Java version is ${javaVersion} and ${failIfNoJavaEnv} is set!`
         );
-        await createRenovateGradlePlugin(workingDir.path);
+      (!gradleSupportsThisJavaVersion || skipJava ? it.skip : it)(
+        `generates a report for Gradle version ${gradleVersion}`,
+        // the function creation is correct and intended
+        // eslint-disable-next-line no-loop-func
+        async () => {
+          await fs.copy(`${fixtures}/minimal-project`, workingDir.path);
+          await fs.copy(
+            `${fixtures}/gradle-wrappers/${gradleVersion}`,
+            workingDir.path
+          );
+          await createRenovateGradlePlugin(workingDir.path);
 
-        const gradlew = path.join(workingDir.path, 'gradlew');
-        await exec(`${gradlew} ${GRADLE_DEPENDENCY_REPORT_OPTIONS}`, {
-          cwd: workingDir.path,
-        });
-        expect(
-          fs.readJSONSync(
-            `${workingDir.path}/${GRADLE_DEPENDENCY_REPORT_FILENAME}`
-          )
-        ).toMatchSnapshot();
-      },
-      120000
-    );
+          const gradlew = path.join(workingDir.path, 'gradlew');
+          await exec(`${gradlew} ${GRADLE_DEPENDENCY_REPORT_OPTIONS}`, {
+            cwd: workingDir.path,
+          });
+          expect(
+            fs.readJSONSync(
+              `${workingDir.path}/${GRADLE_DEPENDENCY_REPORT_FILENAME}`
+            )
+          ).toMatchSnapshot();
+        },
+        120000
+      );
+    }
   });
 });