Create ExperimentalTestRunner which is just the same as BazelTestRunner, but a testbed of upcoming changes, without breaking existing test targets.

To use the alternate test runner a java test should add the tag "experimental_testrunner" and depend on "@bazel_tools//tools/jdk:ExperimentalTestRunner_deploy.jar" (instead of @bazel_tools//tools/jdk:TestRunner_deploy.jar)

--
PiperOrigin-RevId: 149536298
MOS_MIGRATED_REVID=149536298

2 files changed, 29 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaRuleClasses.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaRuleClasses.java
index 2946b297a1..87a02bb547 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaRuleClasses.java
@@ -60,6 +60,8 @@ public class BazelJavaRuleClasses {
       PackageNameConstraint.ANY_SEGMENT, "java", "javatests");
 
   protected static final String JUNIT_TESTRUNNER = "//tools/jdk:TestRunner_deploy.jar";
+  protected static final String EXPERIMENTAL_TESTRUNNER =
+      "//tools/jdk:ExperimentalTestRunner_deploy.jar";
 
   public static final ImplicitOutputsFunction JAVA_BINARY_IMPLICIT_OUTPUTS =
       fromFunctions(
@@ -391,6 +393,17 @@ public class BazelJavaRuleClasses {
                               : null;
                         }
                       }))
+          .add(
+              attr("$experimental_testsupport", LABEL)
+                  .value(
+                      new Attribute.ComputedDefault("use_testrunner") {
+                        @Override
+                        public Object getDefault(AttributeMap rule) {
+                          return rule.get("use_testrunner", Type.BOOLEAN)
+                              ? env.getToolsLabel(EXPERIMENTAL_TESTRUNNER)
+                              : null;
+                        }
+                      }))
           /* <!-- #BLAZE_RULE($base_java_binary).ATTRIBUTE(deploy_manifest_lines) -->
           A list of lines to add to the <code>META-INF/manifest.mf</code> file generated for the
           <code>*_deploy.jar</code> target. The contents of this attribute are <em>not</em> subject
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
index f5fa1ff7ae..d4156ba4f3 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
@@ -80,6 +80,11 @@ public class BazelJavaSemantics implements JavaSemantics {
 
   private static final String JACOCO_COVERAGE_RUNNER_MAIN_CLASS =
       "com.google.testing.coverage.JacocoCoverageRunner";
+  private static final String BAZEL_TEST_RUNNER_MAIN_CLASS =
+      "com.google.testing.junit.runner.BazelTestRunner";
+  private static final String EXPERIMENTAL_TEST_RUNNER_MAIN_CLASS =
+      "com.google.testing.junit.runner.ExperimentalTestRunner";
+  private static final String EXPERIMENTAL_TESTRUNNER_TAG = "experimental_testrunner";
 
   private BazelJavaSemantics() {
   }
@@ -120,13 +125,20 @@ public class BazelJavaSemantics implements JavaSemantics {
     if (mainClass.isEmpty()) {
       if (ruleContext.attributes().get("use_testrunner", Type.BOOLEAN)
           && !useLegacyJavaTest(ruleContext)) {
-        return "com.google.testing.junit.runner.BazelTestRunner";
+        return useExperimentalTestRunner(ruleContext)
+            ? EXPERIMENTAL_TEST_RUNNER_MAIN_CLASS
+            : BAZEL_TEST_RUNNER_MAIN_CLASS;
       }
       mainClass = JavaCommon.determinePrimaryClass(ruleContext, sources);
     }
     return mainClass;
   }
 
+  private static boolean useExperimentalTestRunner(RuleContext ruleContext) {
+    List<String> tags = ruleContext.attributes().get("tags", Type.STRING_LIST);
+    return tags.contains(EXPERIMENTAL_TESTRUNNER_TAG);
+  }
+
   private void checkMainClass(RuleContext ruleContext, ImmutableList<Artifact> sources) {
     boolean createExecutable = ruleContext.attributes().get("create_executable", Type.BOOLEAN);
     String mainClass = getMainClassInternal(ruleContext, sources);
@@ -294,7 +306,9 @@ public class BazelJavaSemantics implements JavaSemantics {
 
     boolean createExecutable = ruleContext.attributes().get("create_executable", Type.BOOLEAN);
     if (createExecutable && ruleContext.attributes().get("use_testrunner", Type.BOOLEAN)) {
-      return Iterables.getOnlyElement(ruleContext.getPrerequisites("$testsupport", Mode.TARGET));
+      String testSupport =
+          useExperimentalTestRunner(ruleContext) ? "$experimental_testsupport" : "$testsupport";
+      return Iterables.getOnlyElement(ruleContext.getPrerequisites(testSupport, Mode.TARGET));
     } else {
       return null;
     }