Add BucketingFunctionTest, this allows rust client side to also run the same test and ensures consistency.

fluss-common/src/test/java/org/apache/fluss/bucketing/BucketingFunctionTest.java

@@ -0,0 +1,128 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.fluss.bucketing;
+
+import org.apache.fluss.metadata.DataLakeFormat;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ /**
+ * Unit tests for {@link BucketingFunction}.
+ * * <p>Maintains parity with Rust client tests to guarantee cross-client 
+ * hashing consistency.
+ */
+ * consistency
+ */
+class BucketingFunctionTest {
+    @Test
+    void testDefaultBucketing() {
+        BucketingFunction defaultBucketing = BucketingFunction.of(null);
+
+        assertThat(defaultBucketing.bucketing(new byte[] {(byte) 0, (byte) 10}, 7)).isEqualTo(1);
+        assertThat(
+                        defaultBucketing.bucketing(
+                                new byte[] {(byte) 0, (byte) 10, (byte) 10, (byte) 10}, 12))
+                .isEqualTo(0);
+        assertThat(
+                        defaultBucketing.bucketing(
+                                "2bb87d68-baf9-4e64-90f9-f80910419fa6"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                16))
+                .isEqualTo(6);
+        assertThat(
+                        defaultBucketing.bucketing(
+                                "The quick brown fox jumps over the lazy dog"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                8))
+                .isEqualTo(6);
+    }
+
+    @Test
+    void testPaimonBucketing() {
+        BucketingFunction paimonBucketing = BucketingFunction.of(DataLakeFormat.PAIMON);
+
+        assertThat(paimonBucketing.bucketing(new byte[] {(byte) 0, (byte) 10}, 7)).isEqualTo(1);
+        assertThat(
+                        paimonBucketing.bucketing(
+                                new byte[] {(byte) 0, (byte) 10, (byte) 10, (byte) 10}, 12))
+                .isEqualTo(11);
+        assertThat(
+                        paimonBucketing.bucketing(
+                                "2bb87d68-baf9-4e64-90f9-f80910419fa6"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                16))
+                .isEqualTo(12);
+        assertThat(
+                        paimonBucketing.bucketing(
+                                "The quick brown fox jumps over the lazy dog"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                8))
+                .isEqualTo(0);
+    }
+
+    @Test
+    void testLanceBucketing() {
+        BucketingFunction lanceBucketing = BucketingFunction.of(DataLakeFormat.LANCE);
+
+        assertThat(lanceBucketing.bucketing(new byte[] {(byte) 0, (byte) 10}, 7)).isEqualTo(1);
+        assertThat(
+                        lanceBucketing.bucketing(
+                                new byte[] {(byte) 0, (byte) 10, (byte) 10, (byte) 10}, 12))
+                .isEqualTo(0);
+        assertThat(
+                        lanceBucketing.bucketing(
+                                "2bb87d68-baf9-4e64-90f9-f80910419fa6"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                16))
+                .isEqualTo(6);
+        assertThat(
+                        lanceBucketing.bucketing(
+                                "The quick brown fox jumps over the lazy dog"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                8))
+                .isEqualTo(6);
+    }
+
+    @Test
+    void testIcebergBucketing() {
+        BucketingFunction icebergBucketing = BucketingFunction.of(DataLakeFormat.ICEBERG);
+
+        assertThat(icebergBucketing.bucketing(new byte[] {(byte) 0, (byte) 10}, 7)).isEqualTo(3);
+        assertThat(
+                        icebergBucketing.bucketing(
+                                new byte[] {(byte) 0, (byte) 10, (byte) 10, (byte) 10}, 12))
+                .isEqualTo(4);
+        assertThat(
+                        icebergBucketing.bucketing(
+                                "2bb87d68-baf9-4e64-90f9-f80910419fa6"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                16))
+                .isEqualTo(12);
+        assertThat(
+                        icebergBucketing.bucketing(
+                                "The quick brown fox jumps over the lazy dog"
+                                        .getBytes(StandardCharsets.UTF_8),
+                                8))
+                .isEqualTo(3);
+    }
+}