[build] Parallelize tests (#3764)

Introduces parallel gradle execution of all the modules. Also, runs
JUnit tests in parallel.

With this change the JUnit tests run faster. This removes the need for
separating "slow" tests in CI and during publishing. Also, because the
modules are executed in parallel, the overall time is better. As an
expected outcome, our Gradle workflow files should be simplified.

Resolves #2270

.github/workflows/ci.yml

@@ -39,8 +39,8 @@ jobs:
           echo -e "   \033[38;5;0;48;5;255m ./gradlew japicmp \033[0m"
           echo ""
           exit -1
-  core-fast:
-    name: core fast tests
+  core:
+    name: core tests
     runs-on: ubuntu-latest
     needs: preliminary
     steps:
@@ -52,21 +52,7 @@ jobs:
     - uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # tag=v3
       name: gradle
       with:
-        arguments: :reactor-core:test --no-daemon -Pjunit-tags=!slow
-  core-slow:
-    name: core slower tests
-    runs-on: ubuntu-latest
-    needs: preliminary
-    steps:
-    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # tag=v4
-    - uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # tag=v3
-      with:
-        distribution: 'temurin'
-        java-version: 8
-    - uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # tag=v3
-      name: gradle
-      with:
-        arguments: :reactor-core:test --no-daemon -Pjunit-tags=slow
+        arguments: :reactor-core:test --no-daemon
   other:
     name: other tests
     runs-on: ubuntu-latest

.github/workflows/publish.yml

@@ -34,30 +34,13 @@ jobs:
       id: checks
       uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # tag=v3
       with:
-        arguments: check -Pjunit-tags=!slow -x jcstress
-
-  slowerChecks:
-    # similar limitations as in prepare, but we parallelize slower tests here
-    name: slowerChecks
-    runs-on: ubuntu-20.04
-    steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # tag=v4
-      - name: setup java
-        uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # tag=v3
-        with:
-          distribution: 'temurin'
-          java-version: 8
-      - name: run slower tests
-        id: slowerTests
-        uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # tag=v3
-        with:
-          arguments: reactor-core:test -Pjunit-tags=slow -Pjcstress.mode=sanity
+        arguments: check -x jcstress
 
   #deploy the snapshot artifacts to Artifactory
   deploySnapshot:
     name: deploySnapshot
     runs-on: ubuntu-20.04
-    needs: [ prepare, slowerChecks ]
+    needs: prepare
     if: needs.prepare.outputs.versionType == 'SNAPSHOT'
     environment: snapshots
     steps:
@@ -77,7 +60,7 @@ jobs:
   deployMilestone:
     name: deployMilestone
     runs-on: ubuntu-20.04
-    needs: [ prepare, slowerChecks ]
+    needs: prepare
     if: needs.prepare.outputs.versionType == 'MILESTONE'
     environment: releases
     steps:
@@ -99,7 +82,7 @@ jobs:
   deployRelease:
     name: deployRelease
     runs-on: ubuntu-20.04
-    needs: [ prepare, slowerChecks ]
+    needs: prepare
     if: needs.prepare.outputs.versionType == 'RELEASE'
     environment: releases
     steps:

gradle.properties

@@ -1,2 +1,4 @@
 version=3.4.37-SNAPSHOT
 bomVersion=2020.0.42
+
+org.gradle.parallel=true

reactor-core/build.gradle

@@ -259,6 +259,7 @@ task loops(type: Test, group: 'verification') {
 }
 
 test {
+  maxParallelForks = Math.max(Runtime.runtime.availableProcessors() - 1, 1)
   def tags = rootProject.findProperty("junit-tags")
   if (tags != null) {
 	println "junit5 tags for core: $tags"

reactor-tools/build.gradle

@@ -188,6 +188,9 @@ javaAgentTest {
 }
 project.tasks.check.dependsOn(javaAgentTest)
 
+// This is required when org.gradle.parallel=true as tests in this module conflict with
+// concurrently running BlockHound tests.
+project.tasks.each {it.mustRunAfter(":reactor-core:blockHoundTest")}
 project.tasks.buildPluginTest.mustRunAfter(shadowJar)
 project.tasks.buildPluginTest.dependsOn(shadowJar)