Implemented JqwikSession.getRandom() and JqwikSession.start(seed)

jqwik-team · Jul 12, 2024 · a6dc73f · a6dc73f
1 parent a502e1f
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diff --git a/TODO.md b/TODO.md
@@ -1,8 +1,8 @@
 # 1.9.1
 
     - JqwikSession:
-      - setRandomSessionSeed(), getRandomSessionSeed()
       - see https://github.com/jqwik-team/jqwik/issues/581
+      - Document in user guide
 
 
 # 1.9.x

diff --git a/api/src/main/java/net/jqwik/api/sessions/JqwikSession.java b/api/src/main/java/net/jqwik/api/sessions/JqwikSession.java
@@ -1,6 +1,9 @@
 package net.jqwik.api.sessions;
 
+import java.util.*;
+
 import org.apiguardian.api.*;
+import org.jspecify.annotations.*;
 
 import net.jqwik.api.*;
 import net.jqwik.api.lifecycle.*;
@@ -30,19 +33,21 @@ public abstract static class JqwikSessionFacade {
 			implementation = FacadeLoader.load(JqwikSession.JqwikSessionFacade.class);
 		}
 
-		public abstract void startSession();
-
 		public abstract void finishSession();
 
 		public abstract void finishTry();
 
 		public abstract boolean isSessionOpen();
 
-		public abstract void runInSession(Runnable runnable);
+		public abstract void runInSession(@Nullable String randomSeed, Runnable runnable);
+
+		public abstract Optional<Random> getRandom();
+
+		public abstract void startSession(@Nullable String randomSeed);
 	}
 
 	public synchronized static void start() {
-		JqwikSessionFacade.implementation.startSession();
+		JqwikSessionFacade.implementation.startSession(null);
 	}
 
 	public static boolean isActive() {
@@ -58,8 +63,34 @@ public synchronized static void finishTry() {
 	}
 
 	public synchronized static void run(Runnable runnable) {
-		JqwikSessionFacade.implementation.runInSession(runnable);
+		JqwikSessionFacade.implementation.runInSession(null, runnable);
 	}
 
+	/**
+	 * Returns the {@linkplain Random} instance associated with the current session.
+	 * @return a Random instance if a session is active, otherwise an empty Optional
+	 */
+	@API(status = EXPERIMENTAL, since = "1.9.1")
+	public static Optional<Random> getRandom() {
+		return JqwikSessionFacade.implementation.getRandom();
+	}
+
+	/**
+	 * Starts a new session with a given random seed.
+	 * Currently seeds must be strings that can be parsed by {@linkplain Long#parseLong(String)}.
+	 */
+	@API(status = EXPERIMENTAL, since = "1.9.1")
+	public static void start(String randomSeed) {
+		JqwikSessionFacade.implementation.startSession(randomSeed);
+	}
+
+	/**
+	 * Runs a given {@linkplain Runnable} in a new session with a given random seed.
+	 * Currently seeds must be strings that can be parsed by {@linkplain Long#parseLong(String)}.
+	 */
+	@API(status = EXPERIMENTAL, since = "1.9.1")
+	public static void run(String randomSeed, Runnable runnable) {
+		JqwikSessionFacade.implementation.runInSession(randomSeed, runnable);
+	}
 
 }
diff --git a/engine/src/main/java/net/jqwik/engine/facades/JqwikSessionFacadeImpl.java b/engine/src/main/java/net/jqwik/engine/facades/JqwikSessionFacadeImpl.java
@@ -1,12 +1,15 @@
 package net.jqwik.engine.facades;
 
+import java.util.*;
 import java.util.logging.*;
 
+import org.jspecify.annotations.*;
 import org.junit.platform.engine.*;
 import org.junit.platform.engine.support.descriptor.*;
 
 import net.jqwik.api.*;
 import net.jqwik.api.sessions.*;
+import net.jqwik.engine.*;
 import net.jqwik.engine.execution.lifecycle.*;
 import net.jqwik.engine.support.*;
 
@@ -29,18 +32,6 @@ public Type getType() {
 		}
 	};
 
-	@Override
-	public void startSession() {
-		if (!CurrentTestDescriptor.isEmpty()) {
-			if (CurrentTestDescriptor.get() == SESSION_DESCRIPTOR) {
-				throw new JqwikException("JqwikSession.start() cannot be nested");
-			} else {
-				throw new JqwikException("JqwikSession.start() must only be used outside jqwik's standard lifecycle");
-			}
-		}
-		CurrentTestDescriptor.push(SESSION_DESCRIPTOR);
-	}
-
 	@Override
 	public void finishSession() {
 		if (!isSessionOpen()) {
@@ -65,8 +56,11 @@ public boolean isSessionOpen() {
 	}
 
 	@Override
-	public void runInSession(JqwikSession.Runnable runnable) {
+	public void runInSession(@Nullable String randomSeed, JqwikSession.Runnable runnable) {
 		try {
+			if (randomSeed != null) {
+				SourceOfRandomness.create(randomSeed);
+			}
 			JqwikSession.start();
 			runnable.run();
 		} catch (Throwable t) {
@@ -81,4 +75,33 @@ private void finishSessionLifecycle() {
 		StoreRepository.getCurrent().finishProperty(SESSION_DESCRIPTOR);
 		StoreRepository.getCurrent().finishScope(SESSION_DESCRIPTOR);
 	}
+
+	@Override
+	public Optional<Random> getRandom() {
+		if (!isSessionOpen()) {
+			return Optional.empty();
+		}
+		return Optional.of(SourceOfRandomness.current());
+	}
+
+	@Override
+	public void startSession(@Nullable String randomSeed) {
+		if (randomSeed != null) {
+			SourceOfRandomness.create(randomSeed);
+		}
+		startSession();
+	}
+
+	private void startSession() {
+		if (!CurrentTestDescriptor.isEmpty()) {
+			if (CurrentTestDescriptor.get() == SESSION_DESCRIPTOR) {
+				throw new JqwikException("JqwikSession.start() cannot be nested");
+			} else {
+				throw new JqwikException("JqwikSession.start() must only be used outside jqwik's standard lifecycle");
+			}
+		}
+		CurrentTestDescriptor.push(SESSION_DESCRIPTOR);
+	}
+
+
 }
diff --git a/engine/src/test/java/net/jqwik/UseArbitrariesOutsideJqwikTests.java b/engine/src/test/java/net/jqwik/UseArbitrariesOutsideJqwikTests.java
@@ -6,7 +6,6 @@
 import org.junit.jupiter.api.*;
 
 import net.jqwik.api.*;
-import net.jqwik.api.Disabled;
 import net.jqwik.api.arbitraries.*;
 import net.jqwik.api.lifecycle.*;
 import net.jqwik.api.providers.*;
@@ -182,13 +181,69 @@ void runInSession() {
 		}
 
 		@Test
-		@Disabled("Not implemented yet")
-		void startWithRandomSeed() {
-			// JqwikSession.start("1234");
-			// or
-			// JqwikSession.run("1234", () -> { ... });
+		void inactiveSessionHasNoRandom() {
+			assertThat(JqwikSession.getRandom()).isEmpty();
 		}
 
+		@Test
+		void accessRandomInActiveSession() {
+			JqwikSession.start();
+			Optional<Random> optionalRandom = JqwikSession.getRandom();
+			assertThat(optionalRandom).isPresent();
+			Random random = optionalRandom.get();
+			assertThat(random.nextInt()).isNotZero();
+
+			// Trigger some random generation
+			assertThat(
+				Arbitraries.strings().sampleStream().limit(5)
+			).hasSize(5);
+
+			assertThat(JqwikSession.getRandom()).hasValue(random);
+		}
+
+		@Test
+		void startSessionWithGivenRandomSeed() {
+			Arbitrary<String> strings = Arbitraries.strings().alpha().ofMaxLength(5);
+
+			JqwikSession.start("42");
+			List<String> generatedValues = strings.sampleStream().limit(10).collect(Collectors.toList());
+			JqwikSession.finish();
+
+			JqwikSession.start("42");
+			assertThat(strings.sampleStream().limit(10).collect(Collectors.toList()))
+				.isEqualTo(generatedValues);
+			JqwikSession.finish();
+
+			JqwikSession.start("4242");
+			assertThat(strings.sampleStream().limit(10).collect(Collectors.toList()))
+				.isNotEqualTo(generatedValues);
+			JqwikSession.finish();
+		}
+
+		@Test
+		void runInSessionWithGivenRandomSeed() {
+			Arbitrary<String> strings = Arbitraries.strings().alpha().ofMaxLength(5);
+			List<String> generatedValues = new ArrayList<>();
+
+			JqwikSession.run("42", () -> {
+				strings.sampleStream().limit(10).forEach(generatedValues::add);
+			});
+
+			JqwikSession.run("42", () -> {
+				assertThat(
+					strings.sampleStream().limit(10).collect(Collectors.toList())
+				).isEqualTo(generatedValues);
+			});
+
+			JqwikSession.run("4243", () -> {
+				assertThat(
+					strings.sampleStream().limit(10).collect(Collectors.toList())
+				).isNotEqualTo(generatedValues);
+			});
+		}
+
+
+
 	}
 
 	private static class PersonProvider implements ArbitraryProvider {