Allow running Java+Ruby tests on Windows separately

This commit allows separate running of Java and Ruby tests on Windows
i.e. the same way as we currently do on unix (`unit_tests.sh`)
via a cli argument.

If no argument has been supplied, both tests are run (as it does now).

The wrapper script is also rewritten from old batch style script to
powershell.

Relates elastic#15566

.buildkite/scripts/exhaustive-tests/generate-steps.py

@@ -38,7 +38,7 @@ def compat_linux_step(imagesuffix: str) -> dict[str, typing.Any]:
 
 
 def compat_windows_step(imagesuffix: str) -> dict[str, typing.Any]:
-    windows_command = LiteralScalarString(r'''$$env:WORKSPACE=$$PWD.Path ; .\\ci\\unit_tests.bat''')
+    windows_command = LiteralScalarString(r'''.\\ci\\unit_tests.ps1''')
 
     return compat_step(imagesuffix, command=windows_command)
 

.buildkite/scripts/jdk-matrix-tests/launch-command.ps1

@@ -14,9 +14,6 @@ param (
 # expand previous buildkite folded section (command invocation)
 Write-Host "^^^ +++"
 
-# the unit test script expects the WORKSPACE env var
-$env:WORKSPACE = $PWD.Path
-
 # unset generic JAVA_HOME
 if (Test-Path env:JAVA_HOME) {
     Remove-Item -Path env:JAVA_HOME

ci/unit_tests.ps1

@@ -0,0 +1,58 @@
+<#
+.SYNOPSIS
+    This is a gradle wrapper script to help run the Logstash unit tests on Windows.
+
+.PARAMETER UnnamedArgument1
+    Optionally allows to specify a subset of tests.
+    Allows values are "ruby" or "java".
+    If unset, all tests are executed.
+
+.EXAMPLE
+    .\ci\unit_tests.ps1
+    Runs all unit tests.
+
+    .\ci\unit_tests.ps1 java
+    Runs only Java unit tests.
+#>
+
+$selectedTestSuite="all"
+
+if ($args.Count -eq 1) {
+    $selectedTestSuite=$args[0]
+}
+
+if (Test-Path Env:BUILD_JAVA_HOME) {    
+    if (Test-Path Env:GRADLE_OPTS) {    
+        $env:GRADLE_OPTS=$env:GRADLE_OPTS + " " + "-Dorg.gradle.java.home=" + $env:BUILD_JAVA_HOME
+    } else {
+        $env:GRADLE_OPTS="-Dorg.gradle.java.home=" + $env:BUILD_JAVA_HOME
+    }
+}
+
+$testOpts = "GRADLE_OPTS: $env:GRADLE_OPTS, BUILD_JAVA_HOME: $env:BUILD_JAVA_HOME"
+
+try {
+    if ($selectedTestSuite -eq "java") {
+        Write-Host "~~~ :java: Running Java tests via Gradle using $testOpts"
+        $CIScript = ".\gradlew.bat javaTests --console=plain --no-daemon --info"
+        Invoke-Expression $CIScript
+    }
+    elseif ($selectedTestSuite -eq "ruby") {
+        Write-Host "~~~ :ruby: Running Ruby tests via Gradle using $testOpts"
+        $CIScript = ".\gradlew.bat rubyTests --console=plain --no-daemon --info"
+        Invoke-Expression $CIScript
+    }
+    else {
+        Write-Host "~~~ 🧪 Running all tests via Gradle using $testOpts"
+        $CIScript = ".\gradlew.bat test --console=plain --no-daemon --info"
+        Invoke-Expression $CIScript
+    }
+
+    if ($LASTEXITCODE -ne 0) {
+        throw "Test script $CIScript failed with a non-zero code: $LASTEXITCODE"
+    }
+} catch {
+    # tests failed
+    Write-Host "^^^ +++"
+    exit 1
+}