Start on RandomnessExtension

Author: leonard84

spock-core/src/main/java/org/spockframework/runtime/extension/builtin/RandomnessConfig.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+
+package org.spockframework.runtime.extension.builtin;
+
+import spock.config.ConfigurationObject;
+
+import java.util.Optional;
+
+@ConfigurationObject("randomness")
+public class RandomnessConfig {
+  public static final String SEED_KEY = "spock.randomness.seed";
+  Object seed = Optional.of((Object) System.getProperty(SEED_KEY)).orElseGet(System::currentTimeMillis);
+  boolean printSeedValueOnStart = false;
+  boolean printSeedValueOnFirstUse = true;
+}

spock-core/src/main/java/org/spockframework/runtime/extension/builtin/RandomnessExtension.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+
+package org.spockframework.runtime.extension.builtin;
+
+import org.spockframework.runtime.extension.IGlobalExtension;
+import org.spockframework.runtime.extension.IMethodInvocation;
+import org.spockframework.runtime.extension.ISpockExecution;
+import org.spockframework.runtime.extension.IStore;
+import org.spockframework.util.Checks;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.Supplier;
+
+public class RandomnessExtension implements IGlobalExtension {
+  private static final IStore.Namespace NAMESPACE = IStore.Namespace.create(RandomnessExtension.class);
+
+  private final RandomnessConfig config;
+
+  public RandomnessExtension(RandomnessConfig config) {
+    this.config = config;
+  }
+
+
+  long getSeedValue() {
+    Object seed = config.seed;
+    Checks.notNull(seed, () -> "seed must not be null");
+    if (seed instanceof Number) {
+      return ((Number) seed).longValue();
+    }
+    String stringRepresentation = String.valueOf(seed);
+    try {
+      return Long.parseLong(stringRepresentation);
+    } catch (NumberFormatException ignore) {
+    }
+    return stringRepresentation.hashCode();
+  }
+
+  @Override
+  public void executionStart(ISpockExecution spockExecution) {
+    long seedValue = getSeedValue();
+    if (config.printSeedValueOnStart) {
+      printSeedValue(seedValue);
+      spockExecution.getStore(NAMESPACE).put("randomnessSource", ((RandomnessSource) () -> new Random(seedValue)));
+    } else if (config.printSeedValueOnFirstUse) {
+      AtomicBoolean printed = new AtomicBoolean();
+      spockExecution.getStore(NAMESPACE).put("randomnessSource", ((RandomnessSource) () -> {
+        if (printed.compareAndSet(false, true)) {
+          printSeedValue(seedValue);
+        }
+        return new Random(seedValue);
+      }));
+    } else {
+      spockExecution.getStore(NAMESPACE).put("randomnessSource", ((RandomnessSource) () -> new Random(seedValue)));
+    }
+
+  }
+
+  private static void printSeedValue(long seedValue) {
+    System.err.printf("Spock Randomness using seed=%d you can rerun with -D%s=%d%n", seedValue, RandomnessConfig.SEED_KEY, seedValue);
+  }
+
+  public static RandomnessSource getRandomnessSupplier(IMethodInvocation methodInvocation) {
+    return methodInvocation.getStore(NAMESPACE).get("randomnessSource", RandomnessSource.class);
+  }
+
+  @FunctionalInterface
+  public interface RandomnessSource extends Supplier<Random> {
+  }
+}

spock-core/src/main/resources/META-INF/services/org.spockframework.runtime.extension.IGlobalExtension

@@ -1,3 +1,4 @@
 org.spockframework.runtime.extension.builtin.IncludeExcludeExtension
 org.spockframework.runtime.extension.builtin.OptimizeRunOrderExtension
+org.spockframework.runtime.extension.builtin.RandomnessExtension
 org.spockframework.runtime.extension.builtin.UnrollExtension