Add unit tests for BitsSubstitution class (helidon-io#9416)

* Add unit tests for BitsSubstitution class.

* remove unused test dependency

* add test dependency's

* Refactor BitsSubstitutionTest to use assertThat with Hamcrest matchers

integrations/db/h2/pom.xml

@@ -52,6 +52,30 @@
             <artifactId>nativeimage</artifactId>
             <scope>provided</scope>
         </dependency>
+
+        <!-- Test-scoped dependencies. -->
+
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.common.testing</groupId>
+            <artifactId>helidon-common-testing-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.logging</groupId>
+            <artifactId>helidon-logging-jul</artifactId>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <profiles>

integrations/db/h2/src/test/java/io/helidon/integrations/db/h2/BitsSubstitutionTest.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2024 Oracle and/or its affiliates.
+ *
+ * Licensed 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 io.helidon.integrations.db.h2;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+/**
+ * Unit tests for the BitsSubstitution class.
+ */
+class BitsSubstitutionTest {
+
+    /**
+     * Test the compareNotNull method with char arrays.
+     */
+    @Test
+    void testCompareNotNull() {
+        char[] data1 = {'a', 'b', 'c'};
+        char[] data2 = {'a', 'b', 'c'};
+        char[] data3 = {'a', 'b', 'd', 'e'};
+        assertThat(BitsSubstitution.compareNotNull(data1, data2), is(0));
+        assertThat(BitsSubstitution.compareNotNull(data1, data3), is(-1));
+        assertThat(BitsSubstitution.compareNotNull(data3, data1), is(1));
+        assertThat(BitsSubstitution.compareNotNull(data2, data3), is(-1));
+    }
+
+    /**
+     * Test the compareNotNullSigned method with byte arrays.
+     */
+    @Test
+    void testCompareNotNullSigned() {
+        byte[] data1 = {1, 2, 3};
+        byte[] data2 = {1, 2, 3};
+        byte[] data3 = {1, 2, 4};
+        assertThat(BitsSubstitution.compareNotNullSigned(data1, data2), is(0));
+        assertThat(BitsSubstitution.compareNotNullSigned(data1, data3), is(-1));
+        assertThat(BitsSubstitution.compareNotNullSigned(data3, data1), is(1));
+    }
+
+    /**
+     * Test the compareNotNullUnsigned method with byte arrays.
+     */
+    @Test
+    void testCompareNotNullUnsigned() {
+        byte[] data1 = {1, 2, 3};
+        byte[] data2 = {1, 2, 3};
+        byte[] data3 = {1, 2, 4};
+        assertThat(BitsSubstitution.compareNotNullUnsigned(data1, data2), is(0));
+        assertThat(BitsSubstitution.compareNotNullUnsigned(data1, data3), is(-1));
+        assertThat(BitsSubstitution.compareNotNullUnsigned(data3, data1), is(1));
+    }
+
+    /**
+     * Test the readInt method.
+     */
+    @Test
+    void testReadInt() {
+        byte[] data = {0, 0, 0, 1};
+        assertThat(BitsSubstitution.readInt(data, 0), is(1));
+    }
+
+    /**
+     * Test the readIntLE method.
+     */
+    @Test
+    void testReadIntLE() {
+        byte[] data = {1, 0, 0, 0};
+        assertThat(BitsSubstitution.readIntLE(data, 0), is(1));
+    }
+
+    /**
+     * Test the uuidToBytes method.
+     */
+    @Test
+    void testUuidToBytes() {
+        UUID uuid = UUID.randomUUID();
+        byte[] bytes = BitsSubstitution.uuidToBytes(uuid);
+        assertNotNull(bytes);
+        assertThat(bytes.length, is(16));
+    }
+
+    /**
+     * Test the writeInt method.
+     */
+    @Test
+    void testWriteInt() {
+        byte[] data = new byte[4];
+        BitsSubstitution.writeInt(data, 0, 1);
+        assertThat(data, is(new byte[]{0, 0, 0, 1}));
+    }
+
+    /**
+     * Test the writeLong method.
+     */
+    @Test
+    void testWriteLong() {
+        byte[] data = new byte[8];
+        BitsSubstitution.writeLong(data, 0, 1L);
+        assertThat(data, is(new byte[]{0, 0, 0, 0, 0, 0, 0, 1}));
+    }
+
+    /**
+     * Test the writeDouble method.
+     */
+    @Test
+    void testWriteDouble() {
+        byte[] data = new byte[8];
+        BitsSubstitution.writeDouble(data, 0, 1.0);
+        assertThat(data, is(new byte[]{63, -16, 0, 0, 0, 0, 0, 0}));
+    }
+}