Fix Enterprise REST Tests by removing hardcoded cluster version (#970)

[`JobCancelledAfterUpgradeTest` is
failing](https://github.com/hazelcast/hazelcast-mono/pull/968#issuecomment-1973254145)
because the expected Hazelcast version is hardcoded.

Changes:
- Make expected versions dynamic
- Use reflection to populate `CURRENT_CLUSTER_VERSION` &
`PREVIOUS_CLUSTER_VERSION` so they don't need to be incremented in
future
- Convert `VersionsTest` to JUnit5
GitOrigin-RevId: d540246e0f204e5fc34ddbdf2bc69049a8b8e71c

hazelcast/src/main/java/com/hazelcast/internal/cluster/Versions.java

@@ -16,8 +16,15 @@
 
 package com.hazelcast.internal.cluster;
 
+import com.hazelcast.instance.GeneratedBuildProperties;
 import com.hazelcast.version.Version;
 
+import javax.annotation.Nonnull;
+
+import java.lang.reflect.Field;
+import java.text.MessageFormat;
+import java.util.Objects;
+
 public final class Versions {
 
     /**
@@ -65,8 +72,50 @@ public final class Versions {
      */
     public static final Version V5_5 = Version.of(5, 5);
 
-    public static final Version PREVIOUS_CLUSTER_VERSION = V5_4;
-    public static final Version CURRENT_CLUSTER_VERSION = V5_5;
+    @Nonnull
+    public static final Version PREVIOUS_CLUSTER_VERSION;
+    @Nonnull
+    public static final Version CURRENT_CLUSTER_VERSION;
+
+    static {
+        // Dynamically set PREVIOUS_CLUSTER_VERSION & CURRENT_CLUSTER_VERSION by reflection
+
+        Version buildPropertiesVersion = Version.of(GeneratedBuildProperties.VERSION);
+
+        // Find an equivalent version in the existing constant pool
+        Version currentClusterVersionConstant = null;
+
+        // The previous version is assumed to be the declared version lexicographically before CURRENT_CLUSTER_VERSION
+        Version previousHighest = null;
+
+        for (Field field : Versions.class.getFields()) {
+            if (field.getType()
+                    .equals(Version.class)) {
+                try {
+                    Version version = (Version) field.get(null);
+
+                    if (version != null) {
+                        int versionCompareToBuildPropertiesVersion = version.compareTo(buildPropertiesVersion);
+
+                        if (versionCompareToBuildPropertiesVersion == 0) {
+                            currentClusterVersionConstant = version;
+                        } else if (versionCompareToBuildPropertiesVersion < 0
+                                && (previousHighest == null || version.compareTo(previousHighest) > 0)) {
+                            previousHighest = version;
+                        }
+                    }
+                } catch (ReflectiveOperationException e) {
+                    throw new ExceptionInInitializerError(e);
+                }
+            }
+        }
+
+        CURRENT_CLUSTER_VERSION = Objects.requireNonNull(currentClusterVersionConstant,
+                () -> MessageFormat.format("Failed to find matching constant for version {0}", buildPropertiesVersion));
+
+        PREVIOUS_CLUSTER_VERSION = Objects.requireNonNull(previousHighest,
+                () -> MessageFormat.format("Failed to find version preceeding {0}", CURRENT_CLUSTER_VERSION));
+    }
 
     private Versions() {
     }

hazelcast/src/main/java/com/hazelcast/version/Version.java

@@ -90,8 +90,8 @@ public boolean equals(Object o) {
 
     @Override
     public int hashCode() {
-        int result = (int) major;
-        result = 31 * result + (int) minor;
+        int result = major;
+        result = 31 * result + minor;
         return result;
     }
 

hazelcast/src/test/java/com/hazelcast/internal/cluster/VersionsTest.java

@@ -16,33 +16,43 @@
 
 package com.hazelcast.internal.cluster;
 
-import com.hazelcast.test.HazelcastParallelClassRunner;
-import com.hazelcast.test.HazelcastTestSupport;
-import com.hazelcast.test.annotation.ParallelJVMTest;
-import com.hazelcast.test.annotation.QuickTest;
 import com.hazelcast.version.Version;
-import org.junit.Test;
-import org.junit.experimental.categories.Category;
-import org.junit.runner.RunWith;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
 
-import static org.junit.Assert.assertEquals;
-
-@RunWith(HazelcastParallelClassRunner.class)
-@Category({QuickTest.class, ParallelJVMTest.class})
-public class VersionsTest extends HazelcastTestSupport {
+import static com.hazelcast.test.HazelcastTestSupport.assertUtilityConstructor;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+@Tag("com.hazelcast.test.annotation.QuickTest")
+class VersionsTest {
     @Test
-    public void testConstructor() {
+    void testConstructor() {
         assertUtilityConstructor(Versions.class);
     }
 
     @Test
-    public void version_4_0() {
+    void version_4_0() {
         assertEquals(Versions.V4_0, Version.of(4, 0));
     }
 
     @Test
-    public void version_4_1() {
+    void version_4_1() {
         assertEquals(Versions.V4_1, Version.of(4, 1));
     }
+
+    @Test
+    void testParse() {
+        Version version = Versions.CURRENT_CLUSTER_VERSION;
+        assertEquals(version, Version.of(version.toString()));
+    }
+
+    @Test
+    void testCurrentVersion() {
+        assertNotNull(Versions.CURRENT_CLUSTER_VERSION);
+        assertNotNull(Versions.PREVIOUS_CLUSTER_VERSION);
+
+        assertNotEquals(Versions.PREVIOUS_CLUSTER_VERSION, Versions.CURRENT_CLUSTER_VERSION);
+    }
 }