[Test] Separate testAcceptsMismatchedServerlessBuildHash (#122570) (#123485)

This PR moves
TransportServiceHandshakeTests.testAcceptsMismatchedServerlessBuildHash
to its own test job to ensure the expected system property is always set
correctly.

Resolves: #122565
(cherry picked from commit 2eb0d00b8f792fd627ba6dc0304b786877ee8e34)

Co-authored-by: Yang Wang <yang.wang@elastic.co>

server/build.gradle

@@ -146,18 +146,30 @@ if (buildParams.isSnapshotBuild() == false) {
 
 tasks.named("test").configure {
   systemProperty 'es.insecure_network_trace_enabled', 'true'
+  filter {
+    excludeTestsMatching("*.TransportServiceHandshakeTests.testAcceptsMismatchedServerlessBuildHash")
+  }
   excludes << '**/IndexSettingsOverrideTests.class'
 }
 
-TaskProvider<Test> indexSettingsOverrideTest = tasks.register("indexSettingsOverrideTest", Test) {
+// There are tests rely on system properties to be configured differently. They must run in a separate test job
+// since the default does not work for them and configuring the system properties inside the test class/method
+// is too late because fields based on the system properties are often initialized statically.
+TaskProvider<Test> systemPropertiesOverrideTest = tasks.register("systemPropertiesOverrideTest", Test) {
   include '**/IndexSettingsOverrideTests.class'
+  include '**/TransportServiceHandshakeTests.class'
+  filter {
+    includeTestsMatching("*.TransportServiceHandshakeTests.testAcceptsMismatchedServerlessBuildHash")
+    includeTestsMatching("*.IndexSettingsOverrideTests.*")
+  }
   systemProperty 'es.stateless.allow.index.refresh_interval.override', 'true'
+  systemProperty 'es.serverless_transport', 'true'
   classpath = sourceSets.test.runtimeClasspath
   testClassesDirs = sourceSets.test.output.classesDirs
 }
 
 tasks.named("check").configure {
-  dependsOn(indexSettingsOverrideTest)
+  dependsOn(systemPropertiesOverrideTest)
 }
 
 tasks.named("thirdPartyAudit").configure {

server/src/test/java/org/elasticsearch/transport/TransportServiceHandshakeTests.java

@@ -22,7 +22,6 @@ import org.elasticsearch.common.network.NetworkService;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.PageCacheRecycler;
 import org.elasticsearch.core.Releasable;
-import org.elasticsearch.core.SuppressForbidden;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.index.IndexVersions;
@@ -373,40 +372,32 @@ public class TransportServiceHandshakeTests extends ESTestCase {
         assertFalse(transportServiceA.nodeConnected(discoveryNode));
     }
 
-    @SuppressForbidden(reason = "Sets property for testing")
     public void testAcceptsMismatchedServerlessBuildHash() {
         assumeTrue("Current build needs to be a snapshot", Build.current().isSnapshot());
-        assumeTrue("Security manager needs to be disabled", System.getSecurityManager() == null);
-        System.setProperty(TransportService.SERVERLESS_TRANSPORT_SYSTEM_PROPERTY, Boolean.TRUE.toString());   // security manager blocks
-                                                                                                              // this
-        try {
-            final DisruptingTransportInterceptor transportInterceptorA = new DisruptingTransportInterceptor();
-            final DisruptingTransportInterceptor transportInterceptorB = new DisruptingTransportInterceptor();
-            transportInterceptorA.setModifyBuildHash(true);
-            transportInterceptorB.setModifyBuildHash(true);
-            final Settings settings = Settings.builder()
-                .put("cluster.name", "a")
-                .put(IGNORE_DESERIALIZATION_ERRORS_SETTING.getKey(), true) // suppress assertions to test production error-handling
-                .build();
-            final TransportService transportServiceA = startServices(
-                "TS_A",
-                settings,
-                TransportVersion.current(),
-                VersionInformation.CURRENT,
-                transportInterceptorA
-            );
-            final TransportService transportServiceB = startServices(
-                "TS_B",
-                settings,
-                TransportVersion.current(),
-                VersionInformation.CURRENT,
-                transportInterceptorB
-            );
-            AbstractSimpleTransportTestCase.connectToNode(transportServiceA, transportServiceB.getLocalNode(), TestProfiles.LIGHT_PROFILE);
-            assertTrue(transportServiceA.nodeConnected(transportServiceB.getLocalNode()));
-        } finally {
-            System.clearProperty(TransportService.SERVERLESS_TRANSPORT_SYSTEM_PROPERTY);
-        }
+        final DisruptingTransportInterceptor transportInterceptorA = new DisruptingTransportInterceptor();
+        final DisruptingTransportInterceptor transportInterceptorB = new DisruptingTransportInterceptor();
+        transportInterceptorA.setModifyBuildHash(true);
+        transportInterceptorB.setModifyBuildHash(true);
+        final Settings settings = Settings.builder()
+            .put("cluster.name", "a")
+            .put(IGNORE_DESERIALIZATION_ERRORS_SETTING.getKey(), true) // suppress assertions to test production error-handling
+            .build();
+        final TransportService transportServiceA = startServices(
+            "TS_A",
+            settings,
+            TransportVersion.current(),
+            VersionInformation.CURRENT,
+            transportInterceptorA
+        );
+        final TransportService transportServiceB = startServices(
+            "TS_B",
+            settings,
+            TransportVersion.current(),
+            VersionInformation.CURRENT,
+            transportInterceptorB
+        );
+        AbstractSimpleTransportTestCase.connectToNode(transportServiceA, transportServiceB.getLocalNode(), TestProfiles.LIGHT_PROFILE);
+        assertTrue(transportServiceA.nodeConnected(transportServiceB.getLocalNode()));
     }
 
     public void testAcceptsMismatchedBuildHashFromDifferentVersion() {