Fixes 3231: Add a lightweight extension quicker but with more limited…

subprojects/junit-jupiter/src/main/java/org/mockito/junit/jupiter/MockitoLightweightExtension.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2024 Mockito contributors
+ * This program is made available under the terms of the MIT License.
+ */
+package org.mockito.junit.jupiter;
+
+import static org.junit.jupiter.api.extension.ExtensionContext.Namespace.create;
+
+import java.lang.reflect.Field;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.jupiter.api.extension.AfterEachCallback;
+import org.junit.jupiter.api.extension.BeforeEachCallback;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.mockito.Mockito;
+import org.mockito.MockitoSession;
+import org.mockito.ScopedMock;
+import org.mockito.internal.configuration.plugins.Plugins;
+import org.mockito.internal.creation.MockSettingsImpl;
+import org.mockito.internal.framework.DefaultMockitoSession;
+import org.mockito.internal.junit.UniversalTestListener;
+import org.mockito.internal.session.MockitoSessionLoggerAdapter;
+import org.mockito.internal.util.MockUtil;
+import org.mockito.quality.Strictness;
+
+public class MockitoLightweightExtension implements BeforeEachCallback, AfterEachCallback {
+    private static final ExtensionContext.Namespace MOCKITO = create("org.mockito");
+
+    private static final String SESSION = "session", MOCKS = "mocks";
+
+    @SuppressWarnings("rawtypes")
+    private static final MockSettingsImpl SETTING = new MockSettingsImpl();
+
+    private static final Field field;
+
+    static {
+        try {
+            field = DefaultMockitoSession.class.getDeclaredField("listener");
+            field.setAccessible(true);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void beforeEach(final ExtensionContext context) throws Exception {
+        var session =
+                Mockito.mockitoSession()
+                        .logger(new MockitoSessionLoggerAdapter(Plugins.getMockitoLogger()))
+                        .strictness(Strictness.STRICT_STUBS)
+                        .startMocking();
+
+        var listener = (UniversalTestListener) field.get(session);
+        for (var instance : context.getRequiredTestInstances().getAllInstances()) {
+            listen(instance, listener);
+        }
+
+        context.getStore(MOCKITO).put(MOCKS, new HashSet<>());
+        context.getStore(MOCKITO).put(SESSION, session);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public void afterEach(ExtensionContext context) {
+        context.getStore(MOCKITO)
+                .remove(MOCKS, Set.class)
+                .forEach(mock -> ((ScopedMock) mock).closeOnDemand());
+        context.getStore(MOCKITO)
+                .remove(SESSION, MockitoSession.class)
+                .finishMocking(context.getExecutionException().orElse(null));
+    }
+
+    private void listen(Object instance, UniversalTestListener listener)
+            throws IllegalAccessException {
+        for (var field : instance.getClass().getDeclaredFields()) {
+            field.setAccessible(true);
+            var maybeMock = field.get(instance);
+            if (MockUtil.isMock((maybeMock))) {
+                listener.onMockCreated(maybeMock, SETTING);
+            }
+        }
+    }
+}