diff --git a/src/test/java/org/apache/commons/lang3/CharUtils_Test.java b/src/test/java/org/apache/commons/lang3/CharUtils_Test.java
new file mode 100644
index 00000000000..9d3ff859c8e
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/CharUtils_Test.java
@@ -0,0 +1,43 @@
+
+/*
+ * 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.commons.lang3;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class CharUtils_TestPK {
+
+    @ParameterizedTest
+    @CsvSource({
+        "'A', \\u0041" ,  //Printable ASCII
+        "' ', \\u0020" ,  //Space Character
+        "'0', \\u0030" ,  //Digit Character
+        "'z', \\u007a" ,  //Lowercase AsCII
+        "'\u0000', \\u0000",    // Minimum Unicode (null character)
+        "'\uFFFF', \\uffff" ,// Maximum Unicode (U+FFFF)
+        "'\u007F', \\u007f"     // Last ASCII control character
+
+    })
+    void testToUnicodeEscaped_char(char input, String expected){
+        assertEquals(expected, CharUtils.unicodeEscaped(input));
+
+    }
+    
+}
diff --git a/src/test/java/org/apache/commons/lang3/StringUtils_Test.java b/src/test/java/org/apache/commons/lang3/StringUtils_Test.java
new file mode 100644
index 00000000000..3351c3f2f50
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/StringUtils_Test.java
@@ -0,0 +1,56 @@
+/*
+ * 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.commons.lang3;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+
+public class StringUtils_TestPK {
+
+    @Test
+    void testReverseStringIsNull(){
+      assertNull(StringUtils.reverse(null));
+    }
+    @Test 
+    void testReverseStringWithSpaces(){
+        assertEquals("dlrow olleh", StringUtils.reverse("hello world"), 
+        "Failed test when string is : hello world");
+    }
+    @Test 
+    void testReverseSingleCharacter(){
+        assertEquals("p", StringUtils.reverse("p"), 
+        "Failed test when string is : p");
+    }
+    @Test 
+    void testReverseEmptyString(){
+        assertEquals(" ", StringUtils.reverse(" "), 
+        " Failed test when string is Emplty");
+    }
+    @Test 
+    void testReverseString(){
+        assertEquals("dlrow", StringUtils.reverse("world"), 
+        "Failed test when string is : world");
+    }
+    @Test
+    void testReverseWhenUpperCaseAndLowerCase(){
+        assertEquals("dLroW", StringUtils.reverse("WorLd"), 
+        "Failed test when inout is : WorLd");
+    }
+}
diff --git a/src/test/java/org/apache/commons/lang3/math/NumberUtils_Test.java b/src/test/java/org/apache/commons/lang3/math/NumberUtils_Test.java
new file mode 100644
index 00000000000..f6abc9cd88e
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/math/NumberUtils_Test.java
@@ -0,0 +1,119 @@
+/*
+ * 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.commons.lang3.math;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigDecimal;
+
+import org.apache.commons.lang3.ObjectUtils.Null;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class NumberUtils_Test {
+     // parametrized test on max()
+    @ParameterizedTest
+    @CsvSource({
+        "-128 , -128, -128 , -128" , //Test all at min and equal 
+        "127 , 127 , 127 , 127"  ,  //Test all at max and equal value
+        "0 , 0 , 0 ,0 ", //Test all at typical value
+        "-128 , -127 , -126, -126", // Test for all min boundary edge cases
+        "127, 126, 125 , 127", // Test for all max boudary edge cases
+        "-128, 0, 127, 127", //Test across the entire range
+        "-128, 126, 127, 127", // Test with edge value with upper limit
+        "-128, -128, 127, 127" //Test all extreme mix values   
+
+    })
+    void testMaxByte(byte a, byte b, byte c, byte expected) {
+
+       assertEquals(expected, NumberUtils.max(a,b,c),"Failed for inputs: " + a +"," + b + ", " + c);  
+    }
+
+    // white box test on min()
+      
+    @Test
+    void testMinValueNormal(){
+        assertEquals(1, NumberUtils.min(5,3,8,1,7));
+    }
+    @Test
+    void testMinValueAtStart(){
+        assertEquals(1, NumberUtils.min(1,5,3,8,7));
+    }
+    @Test
+    void testMinValueAtEnd(){
+        assertEquals(1, NumberUtils.min(5,3,8,7,1));
+    }
+    @Test
+    void testMinValueWithinNegativeNum(){
+        assertEquals(-8, NumberUtils.min(-5,-3,-8,-1,-7));
+    }
+    @Test
+    void testMinValueWithMixNUmbers(){
+        assertEquals(-8, NumberUtils.min(-5,3,-8,1,-7));
+    }
+    @Test
+    void testMinValueWithSingleElement(){
+        assertEquals(7, NumberUtils.min(7));
+    }
+    //checking test for indirectly calling ValidateArray
+    @Test
+    void testMinNullArray(){
+        assertThrows(NullPointerException.class, () -> NumberUtils.min((int[]) null));
+    }
+    @Test
+    void testMinEmptyArray(){
+        assertThrows(IllegalArgumentException.class, () -> NumberUtils.min ());
+    }
+       
+    //unit test on createBigDecimal() 
+    @Test
+    void testCreateBigDecimalHasNullInput(){
+        //test with input as null
+        assertEquals(null,NumberUtils.createBigDecimal(null),
+         "Expected null when input is null");
+    }
+    @Test
+    void testCreateBigDecimalIsEmptyString(){
+        assertThrows(NumberFormatException.class, () -> {
+            NumberUtils.createBigDecimal("");
+        }, "Expected NumberFormatException when input is empty string");
+    }
+    @Test
+    void testCreateBigDecimalIsBlankString(){
+        assertThrows(NumberFormatException.class, () -> {
+            NumberUtils.createBigDecimal("   ");
+        }, "Expected NumberFormatException when input is a blank string");
+    }
+    @Test
+    void testCreateBigDecimalHasValidInput(){
+        BigDecimal result = NumberUtils.createBigDecimal("123.45");
+        assertNotNull(result, "Expected a valid BigDecimal Object");
+        assertEquals(new BigDecimal("123.45"), result, 
+        "Expected BigDecimal value to be 123.45");
+    }
+    @Test
+    void testCreateBigDecimalHasInvalidInput(){
+        assertThrows(NumberFormatException.class, () -> {
+            NumberUtils.createBigDecimal("abc");
+        }, "Expected NumberFormatException when input is non-numeric string");
+    }
+}