Enable tests to run in parallel by default

CLAUDE.md

@@ -101,7 +101,10 @@ cd package
 ### Testing Commands
 - **Run specific test class**: `mvn test -Dtest=ClassName`
 - **Run tests with specific pattern**: `mvn test -Dtest="*Pattern*"`
+- **Run without slow/benchmark tests**: `mvn test -pl engine -DskipITs -Dgroups='!slow,!benchmark'`
+- **Override fork count** (e.g. all cores): `mvn test -Dforkcount=1C`
 - **Performance tests**: Located in `src/test/java/performance/` packages
+- **Parallel execution**: enabled by default - classes run concurrently across JVM forks; methods within a class run sequentially. Tests that mutate `GlobalConfiguration` are annotated `@ResourceLock("GlobalConfiguration")` to serialize with each other.
 
 ## Codebase Navigation Map
 

CONTRIBUTING.md

@@ -115,6 +115,26 @@ Build and run default tests:
 $ mvn clean install
 ```
 
+Tests run in parallel by default: classes execute concurrently across multiple JVM forks (`forkCount=0.5C`, i.e. half the available CPU cores). No extra flags needed.
+
+Run only unit tests for the engine module, skipping slow/benchmark tests:
+
+```shell
+$ mvn test -pl engine -DskipITs -Dgroups='!slow,!benchmark'
+```
+
+Override the number of parallel JVM forks (e.g. use all cores):
+
+```shell
+$ mvn test -pl engine -DskipITs -Dforkcount=1C
+```
+
+Run a single test class:
+
+```shell
+$ mvn test -pl engine -Dtest=MyTestClass -DskipITs
+```
+
 To run additional integration test locally use:
 
 ```shell

engine/src/main/java/com/arcadedb/GlobalConfiguration.java

@@ -42,20 +42,19 @@ public enum GlobalConfiguration {
   // ENVIRONMENT
   DUMP_CONFIG_AT_STARTUP("arcadedb.dumpConfigAtStartup", SCOPE.JVM, "Dumps the configuration at startup", Boolean.class, false,
       value -> {
-        //dumpConfiguration(System.out);
-
-        try {
-          final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
-          dumpConfiguration(new PrintStream(buffer));
-          if (LogManager.instance() != null)
-            LogManager.instance().log(buffer, Level.WARNING, new String(buffer.toByteArray()));
-          else
-            System.out.println(new String(buffer.toByteArray()));
+        if (Boolean.TRUE.equals(value))
+          try {
+            final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+            dumpConfiguration(new PrintStream(buffer));
+            if (LogManager.instance() != null)
+              LogManager.instance().log(buffer, Level.WARNING, new String(buffer.toByteArray()));
+            else
+              System.out.println(new String(buffer.toByteArray()));
 
-          buffer.close();
-        } catch (IOException e) {
-          System.out.println("Error on printing initial configuration to log (error=" + e + ")");
-        }
+            buffer.close();
+          } catch (IOException e) {
+            System.out.println("Error on printing initial configuration to log (error=" + e + ")");
+          }
 
         return value;
       }),

engine/src/test/java/com/arcadedb/ACIDTransactionTest.java

@@ -48,8 +48,12 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.fail;
+import org.junit.jupiter.api.parallel.Isolated;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
 @Tag("slow")
+@Isolated
+@ResourceLock("GlobalConfiguration")
 class ACIDTransactionTest extends TestHelper {
   @Test
   void asyncTX() {

engine/src/test/java/com/arcadedb/CompareParserAST.java

@@ -7,10 +7,12 @@
 
 import java.util.List;
 import java.util.Map;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
 /**
  * Compares the AST generated by ANTLR and JavaCC parsers for the same MATCH query.
  */
+@ResourceLock("GlobalConfiguration")
 public class CompareParserAST {
   public static void main(String[] args) {
     DatabaseFactory factory = new DatabaseFactory("./target/databases/compare-parser");

engine/src/test/java/com/arcadedb/GlobalConfigurationTest.java

@@ -22,7 +22,9 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
+@ResourceLock("GlobalConfiguration")
 class GlobalConfigurationTest extends TestHelper {
   @Test
   void maxPageRAMAutoTune() {

engine/src/test/java/com/arcadedb/RandomTestMultiThreadsTest.java

@@ -42,7 +42,9 @@
 import java.util.logging.*;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
+@ResourceLock("GlobalConfiguration")
 class RandomTestMultiThreadsTest extends TestHelper {
   private static final int CYCLES           = 10000;
   private static final int STARTING_ACCOUNT = 10000;

engine/src/test/java/com/arcadedb/TestHelper.java

@@ -34,6 +34,8 @@
 
 import java.io.File;
 import java.util.Collection;
+import java.util.EnumMap;
+import java.util.Map;
 import java.util.Random;
 import java.util.UUID;
 import java.util.concurrent.ThreadLocalRandom;
@@ -43,10 +45,13 @@
 import static org.assertj.core.api.Assertions.fail;
 
 public abstract class TestHelper {
-  protected static final int             PARALLEL_LEVEL = 4;
+  protected static final int             PARALLEL_LEVEL    = 4;
   protected final        DatabaseFactory factory;
   protected              Database        database;
-  protected              boolean         autoStartTx    = false;
+  protected              boolean         autoStartTx       = false;
+
+  private static final Object                     ACTIVE_DB_LOCK = new Object();
+  private              Map<GlobalConfiguration, Object> configSnapshot;
 
   public interface DatabaseTest<PAR> {
     void call(PAR iArgument) throws Exception;
@@ -158,6 +163,7 @@ protected void endTest() {
 
   @BeforeEach
   public void beforeTest() {
+    configSnapshot = captureConfigSnapshot();
     GlobalConfiguration.SERVER_ROOT_PATH.setValue("./target");
     if (autoStartTx && !database.isTransactionActive())
       database.begin();
@@ -184,14 +190,28 @@ public void afterTest() {
 
     checkActiveDatabases();
     FileUtils.deleteRecursively(new File(getDatabasePath()));
-    GlobalConfiguration.resetAll();
+    restoreConfigSnapshot(configSnapshot);
   }
 
   @AfterAll
   public static void endAllTests() {
     GlobalConfiguration.resetAll();
   }
 
+  private static Map<GlobalConfiguration, Object> captureConfigSnapshot() {
+    final Map<GlobalConfiguration, Object> snapshot = new EnumMap<>(GlobalConfiguration.class);
+    for (final GlobalConfiguration v : GlobalConfiguration.values())
+      snapshot.put(v, v.getValue());
+    return snapshot;
+  }
+
+  private static void restoreConfigSnapshot(final Map<GlobalConfiguration, Object> snapshot) {
+    if (snapshot == null)
+      return;
+    for (final Map.Entry<GlobalConfiguration, Object> e : snapshot.entrySet())
+      e.getKey().setValue(e.getValue());
+  }
+
   protected String getPerformanceProfile() {
     return "default";
   }
@@ -227,15 +247,17 @@ protected void checkDatabaseIntegrity() {
   }
 
   public static void checkActiveDatabases() {
-    final Collection<Database> activeDatabases = DatabaseFactory.getActiveDatabaseInstances();
+    synchronized (ACTIVE_DB_LOCK) {
+      final Collection<Database> activeDatabases = DatabaseFactory.getActiveDatabaseInstances();
 
-    if (!activeDatabases.isEmpty())
-      LogManager.instance()
-          .log(TestHelper.class, Level.SEVERE, "Found active databases: " + activeDatabases + ". Forced closing...");
+      if (!activeDatabases.isEmpty())
+        LogManager.instance()
+            .log(TestHelper.class, Level.SEVERE, "Found active databases: " + activeDatabases + ". Forced closing...");
 
-    for (final Database db : activeDatabases)
-      db.close();
+      for (final Database db : activeDatabases)
+        db.close();
 
-    assertThat(activeDatabases.isEmpty()).as("Found active databases: " + activeDatabases).isTrue();
+      assertThat(activeDatabases.isEmpty()).as("Found active databases: " + activeDatabases).isTrue();
+    }
   }
 }

engine/src/test/java/com/arcadedb/engine/RecordRecyclingTest.java

@@ -34,8 +34,10 @@
 
 import static com.arcadedb.schema.LocalSchema.STATISTICS_FILE_NAME;
 import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
 @Tag("slow")
+@ResourceLock("GlobalConfiguration")
 class RecordRecyclingTest {
   private final static int    TOT_RECORDS  = 100_000;
   private final static String VERTEX_TYPE  = "Product";

engine/src/test/java/com/arcadedb/engine/TestInsertAndSelectWithThreadBucketSelectionStrategy.java

@@ -34,7 +34,9 @@
 import java.time.format.DateTimeFormatter;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.jupiter.api.parallel.ResourceLock;
 
+@ResourceLock("GlobalConfiguration")
 class TestInsertAndSelectWithThreadBucketSelectionStrategy {
 
   @BeforeEach

engine/src/test/java/com/arcadedb/function/sql/geo/GeoConstructionFunctionsTest.java

@@ -39,7 +39,7 @@ class GeomFromText {
 
     @Test
     void sqlHappyPath() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.geomFromText('POINT (10 20)') as geom");
         assertThat(result.hasNext()).isTrue();
         final Object geom = result.next().getProperty("geom");
@@ -58,7 +58,7 @@ void javaExecuteHappyPath() {
 
     @Test
     void nullInput_sql_returnsNull() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.geomFromText(null) as geom");
         assertThat(result.hasNext()).isTrue();
         final Object geom = result.next().getProperty("geom");
@@ -100,7 +100,7 @@ class Point {
 
     @Test
     void sqlHappyPath() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.point(10, 20) as wkt");
         assertThat(result.hasNext()).isTrue();
         final String wkt = result.next().getProperty("wkt");
@@ -124,7 +124,7 @@ void javaExecuteHappyPath() {
 
     @Test
     void nullFirstArg_sql_returnsNull() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.point(null, 20) as wkt");
         assertThat(result.hasNext()).isTrue();
         final Object wkt = result.next().getProperty("wkt");
@@ -164,7 +164,7 @@ class LineString {
 
     @Test
     void sqlHappyPath() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.lineString([[0,0],[10,10],[20,0]]) as wkt");
         assertThat(result.hasNext()).isTrue();
         final String wkt = result.next().getProperty("wkt");
@@ -193,7 +193,7 @@ void javaExecuteHappyPath() {
 
     @Test
     void nullInput_sql_returnsNull() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.lineString(null) as wkt");
         assertThat(result.hasNext()).isTrue();
         final Object wkt = result.next().getProperty("wkt");
@@ -239,7 +239,7 @@ class Polygon {
 
     @Test
     void sqlHappyPath() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.polygon([[0,0],[10,0],[10,10],[0,10],[0,0]]) as wkt");
         assertThat(result.hasNext()).isTrue();
         final String wkt = result.next().getProperty("wkt");
@@ -265,7 +265,7 @@ void javaExecuteHappyPath() {
 
     @Test
     void nullInput_sql_returnsNull() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.polygon(null) as wkt");
         assertThat(result.hasNext()).isTrue();
         final Object wkt = result.next().getProperty("wkt");
@@ -281,7 +281,7 @@ void nullInput_execute_returnsNull() {
 
     @Test
     void openRing_sql_autoClose() throws Exception {
-      TestHelper.executeInNewDatabase("GeoDatabase", (db) -> {
+      TestHelper.executeInNewDatabase((db) -> {
         final ResultSet result = db.query("sql", "select geo.polygon([[0,0],[10,0],[10,10],[0,10]]) as wkt");
         assertThat(result.hasNext()).isTrue();
         final String wkt = result.next().getProperty("wkt");