Add support for non-fork-join test executor

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/Constants.java

@@ -15,9 +15,11 @@
 import static org.apiguardian.api.API.Status.STABLE;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_CUSTOM_CLASS_PROPERTY_NAME;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_DYNAMIC_FACTOR_PROPERTY_NAME;
+import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_DYNAMIC_TEST_EXECUTOR_PROPERTY_NAME;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_FIXED_MAX_POOL_SIZE_PROPERTY_NAME;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_FIXED_PARALLELISM_PROPERTY_NAME;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_FIXED_SATURATE_PROPERTY_NAME;
+import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_FIXED_TEST_EXECUTOR_PROPERTY_NAME;
 import static org.junit.platform.engine.support.hierarchical.DefaultParallelExecutionConfigurationStrategy.CONFIG_STRATEGY_PROPERTY_NAME;
 
 import org.apiguardian.api.API;
@@ -176,7 +178,7 @@ public final class Constants {
 	 * {@value #PARALLEL_CONFIG_FIXED_PARALLELISM_PROPERTY_NAME}; defaults to
 	 * {@code 256 + fixed.parallelism}.
 	 *
-	 * <p>Note: This property only takes affect on Java 9+.
+	 * <p>Note: This property only takes effect on Java 9+.
 	 *
 	 * @since 5.10
 	 */
@@ -194,14 +196,27 @@ public final class Constants {
 
 	 * <p>Value must either {@code true} or {@code false}; defaults to {@code true}.
 	 *
-	 * <p>Note: This property only takes affect on Java 9+.
+	 * <p>Note: This property only takes effect on Java 9+.
 	 *
 	 * @since 5.10
 	 */
 	@API(status = EXPERIMENTAL, since = "5.10")
 	public static final String PARALLEL_CONFIG_FIXED_SATURATE_PROPERTY_NAME = PARALLEL_CONFIG_PREFIX
 			+ CONFIG_FIXED_SATURATE_PROPERTY_NAME;
 
+	/**
+	 * Property name used to set the type of test executor
+	 * (which directly relates to the type of thread pool used)
+	 * for the {@code fixed} configuration strategy: {@value}
+	 *
+	 * <p>Value must be either {@code fork_join} or {@code fixed_threads}; defaults to {@code fork_join}.
+	 *
+	 * @since 5.11
+	 */
+	@API(status = EXPERIMENTAL, since = "5.11")
+	public static final String PARALLEL_CONFIG_FIXED_TEST_EXECUTOR_PROPERTY_NAME = PARALLEL_CONFIG_PREFIX
+			+ CONFIG_FIXED_TEST_EXECUTOR_PROPERTY_NAME;
+
 	/**
 	 * Property name used to set the factor to be multiplied with the number of
 	 * available processors/cores to determine the desired parallelism for the
@@ -215,6 +230,19 @@ public final class Constants {
 	public static final String PARALLEL_CONFIG_DYNAMIC_FACTOR_PROPERTY_NAME = PARALLEL_CONFIG_PREFIX
 			+ CONFIG_DYNAMIC_FACTOR_PROPERTY_NAME;
 
+	/**
+	 * Property name used to set the type of test executor
+	 * (which directly relates to the type of thread pool used)
+	 * for the {@code dynamic} configuration strategy: {@value}
+	 *
+	 * <p>Value must be either {@code fork_join} or {@code fixed_threads}; defaults to {@code fork_join}.
+	 *
+	 * @since 5.11
+	 */
+	@API(status = EXPERIMENTAL, since = "5.11")
+	public static final String PARALLEL_CONFIG_DYNAMIC_TEST_EXECUTOR_PROPERTY_NAME = PARALLEL_CONFIG_PREFIX
+			+ CONFIG_DYNAMIC_TEST_EXECUTOR_PROPERTY_NAME;
+
 	/**
 	 * Property name used to specify the fully qualified class name of the
 	 * {@link ParallelExecutionConfigurationStrategy} to be used for the

junit-platform-engine/src/main/java/org/junit/platform/engine/support/hierarchical/DefaultParallelExecutionConfiguration.java

@@ -24,15 +24,17 @@ class DefaultParallelExecutionConfiguration implements ParallelExecutionConfigur
 	private final int corePoolSize;
 	private final int keepAliveSeconds;
 	private final Predicate<? super ForkJoinPool> saturate;
+	private final TestExecutor testExecutor;
 
 	DefaultParallelExecutionConfiguration(int parallelism, int minimumRunnable, int maxPoolSize, int corePoolSize,
-			int keepAliveSeconds, Predicate<? super ForkJoinPool> saturate) {
+			int keepAliveSeconds, Predicate<? super ForkJoinPool> saturate, TestExecutor testExecutor) {
 		this.parallelism = parallelism;
 		this.minimumRunnable = minimumRunnable;
 		this.maxPoolSize = maxPoolSize;
 		this.corePoolSize = corePoolSize;
 		this.keepAliveSeconds = keepAliveSeconds;
 		this.saturate = saturate;
+		this.testExecutor = testExecutor;
 	}
 
 	@Override
@@ -64,4 +66,9 @@ public int getKeepAliveSeconds() {
 	public Predicate<? super ForkJoinPool> getSaturatePredicate() {
 		return saturate;
 	}
+
+	@Override
+	public TestExecutor getTestExecutor() {
+		return testExecutor;
+	}
 }

junit-platform-engine/src/main/java/org/junit/platform/engine/support/hierarchical/DefaultParallelExecutionConfigurationStrategy.java

@@ -12,6 +12,7 @@
 
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.apiguardian.api.API.Status.STABLE;
+import static org.junit.platform.engine.support.hierarchical.ParallelExecutionConfiguration.TestExecutor;
 
 import java.math.BigDecimal;
 import java.util.Locale;
@@ -21,6 +22,7 @@
 import org.junit.platform.commons.util.Preconditions;
 import org.junit.platform.commons.util.ReflectionUtils;
 import org.junit.platform.engine.ConfigurationParameters;
+import org.junit.platform.engine.TestDescriptor;
 
 /**
  * Default implementations of configuration strategies for parallel test
@@ -49,8 +51,11 @@ public ParallelExecutionConfiguration createConfiguration(ConfigurationParameter
 			boolean saturate = configurationParameters.get(CONFIG_FIXED_SATURATE_PROPERTY_NAME,
 				Boolean::valueOf).orElse(true);
 
+			TestExecutor testExecutor = configurationParameters.get(CONFIG_FIXED_TEST_EXECUTOR_PROPERTY_NAME,
+				(str) -> TestExecutor.valueOf(str.toUpperCase())).orElse(TestExecutor.FORK_JOIN);
+
 			return new DefaultParallelExecutionConfiguration(parallelism, parallelism, maxPoolSize, parallelism,
-				KEEP_ALIVE_SECONDS, __ -> saturate);
+				KEEP_ALIVE_SECONDS, __ -> saturate, testExecutor);
 		}
 	},
 
@@ -84,8 +89,11 @@ public ParallelExecutionConfiguration createConfiguration(ConfigurationParameter
 			boolean saturate = configurationParameters.get(CONFIG_DYNAMIC_SATURATE_PROPERTY_NAME,
 				Boolean::valueOf).orElse(true);
 
+			TestExecutor testExecutor = configurationParameters.get(CONFIG_DYNAMIC_TEST_EXECUTOR_PROPERTY_NAME,
+				(str) -> TestExecutor.valueOf(str.toUpperCase())).orElse(TestExecutor.FORK_JOIN);
+
 			return new DefaultParallelExecutionConfiguration(parallelism, parallelism, maxPoolSize, parallelism,
-				KEEP_ALIVE_SECONDS, __ -> saturate);
+				KEEP_ALIVE_SECONDS, __ -> saturate, testExecutor);
 		}
 	},
 
@@ -163,6 +171,16 @@ public ParallelExecutionConfiguration createConfiguration(ConfigurationParameter
 	@API(status = EXPERIMENTAL, since = "1.10")
 	public static final String CONFIG_FIXED_SATURATE_PROPERTY_NAME = "fixed.saturate";
 
+	/**
+	 * Property name used to disable saturation of the underlying thread pool
+	 * used to execute {@linkplain TestDescriptor.Type#TEST test tasks}
+	 * for the {@link #FIXED} configuration strategy.
+	 *
+	 * @since 1.11
+	 */
+	@API(status = EXPERIMENTAL, since = "1.11")
+	public static final String CONFIG_FIXED_TEST_EXECUTOR_PROPERTY_NAME = "fixed.test-executor";
+
 	/**
 	 * Property name of the factor used to determine the desired parallelism for the
 	 * {@link #DYNAMIC} configuration strategy.
@@ -207,6 +225,16 @@ public ParallelExecutionConfiguration createConfiguration(ConfigurationParameter
 	@API(status = EXPERIMENTAL, since = "1.10")
 	public static final String CONFIG_DYNAMIC_SATURATE_PROPERTY_NAME = "dynamic.saturate";
 
+	/**
+	 * Property name used to disable saturation of the underlying thread pool
+	 * used to execute {@linkplain TestDescriptor.Type#TEST test tasks}
+	 * for the {@link #DYNAMIC} configuration strategy.
+	 *
+	 * @since 1.11
+	 */
+	@API(status = EXPERIMENTAL, since = "1.11")
+	public static final String CONFIG_DYNAMIC_TEST_EXECUTOR_PROPERTY_NAME = "dynamic.test-executor";
+
 	/**
 	 * Property name used to specify the fully qualified class name of the
 	 * {@link ParallelExecutionConfigurationStrategy} to be used by the