diff --git a/src/test/java/org/apache/commons/lang3/ObjectUtilsFirstNonNullTest.java b/src/test/java/org/apache/commons/lang3/ObjectUtilsFirstNonNullTest.java
new file mode 100644
index 00000000000..a2a4d30a351
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/ObjectUtilsFirstNonNullTest.java
@@ -0,0 +1,49 @@
+/*
+ * 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 org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ObjectUtilsFirstNonNullTest {
+
+    @Test
+    public void testFirstNonNullWithValidValues() {
+        String result = ObjectUtils.firstNonNull(null, null, "first", "second");
+        assertEquals("first", result);
+    }
+
+    @Test
+    public void testFirstNonNullAllNulls() {
+    String result = ObjectUtils.firstNonNull(null, null, null);
+    assertNull(result, "Expected result to be null when all inputs are null");
+    }
+
+    @Test
+    public void testFirstNonNullSingleValue() {
+        Integer value = ObjectUtils.firstNonNull(42);
+        assertEquals(42, value);
+    }
+
+    @Test
+    public void testFirstNonNullWithMixedTypes() {
+        Number result = ObjectUtils.firstNonNull(null, 3.14, 100L);
+        assertEquals(3.14, result);
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/org/apache/commons/lang3/StringsUtilCapitalizeTest.java b/src/test/java/org/apache/commons/lang3/StringsUtilCapitalizeTest.java
new file mode 100644
index 00000000000..3389d87bfd2
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/StringsUtilCapitalizeTest.java
@@ -0,0 +1,64 @@
+/*
+ * 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.junit.jupiter.api.Test;
+
+
+public class StringsUtilCapitalizeTest {
+      @Test
+    void capitalize_NormalLowercaseWord_ReturnsCapitalized() {
+        assertEquals("Hello", StringUtils.capitalize("hello"));
+    }
+
+    @Test
+    void capitalize_AlreadyCapitalizedWord_ReturnsSameString() {
+        assertEquals("Hello", StringUtils.capitalize("Hello"));
+    }
+
+    @Test
+    void capitalize_AllUppercaseWord_ReturnsSameString() {
+        assertEquals("HELLO", StringUtils.capitalize("HELLO"));
+    }
+
+    @Test
+    void capitalize_EmptyString_ReturnsSameString() {
+        assertEquals("", StringUtils.capitalize(""));
+    }
+
+    @Test
+    void capitalize_NullInput_ReturnsNull() {
+        assertNull(StringUtils.capitalize(null));
+    }
+
+    @Test
+    void capitalize_SingleLowercaseChar_ReturnsCapitalizedChar() {
+        assertEquals("A", StringUtils.capitalize("a"));
+    }
+
+    @Test
+    void capitalize_NonLetterFirstChar_ReturnsSameString() {
+        assertEquals("1hello", StringUtils.capitalize("1hello"));
+    }
+
+    @Test
+    void capitalize_WhitespaceOnly_ReturnsSameString() {
+        assertEquals("   ", StringUtils.capitalize("   "));
+    }
+}
diff --git a/src/test/java/org/apache/commons/lang3/UtilsStringIntegrationTest.java b/src/test/java/org/apache/commons/lang3/UtilsStringIntegrationTest.java
new file mode 100644
index 00000000000..01ce55934ff
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/UtilsStringIntegrationTest.java
@@ -0,0 +1,46 @@
+/*
+ * 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 org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class UtilsStringIntegrationTest {
+
+   
+    @Test
+    public void testTextNormalizationScenario() {
+        String rawInput = "   Héllò     Wórld!   ";
+
+        //Trim the string (removes leading/trailing whitespace)
+        String trimmed = StringUtils.trim(rawInput);
+        assertEquals("Héllò     Wórld!", trimmed, "Trim step failed");
+
+        //Remove accents (Héllò → Hello, Wórld → World)
+        String noAccents = StringUtils.stripAccents(trimmed);
+        assertEquals("Hello     World!", noAccents, "Accent stripping failed");
+
+        //Normalize internal whitespace (collapse multiple spaces to one)
+        String normalizedSpace = StringUtils.normalizeSpace(noAccents);
+        assertEquals("Hello World!", normalizedSpace, "Space normalization failed");
+
+        //Convert to lowercase
+        String finalResult = normalizedSpace.toLowerCase();
+        assertEquals("hello world!", finalResult, "Lowercasing failed");
+    }    
+}
diff --git a/src/test/java/org/apache/commons/lang3/math/NumberUtilsIsCreatableTest.java b/src/test/java/org/apache/commons/lang3/math/NumberUtilsIsCreatableTest.java
new file mode 100644
index 00000000000..2a650d3be4e
--- /dev/null
+++ b/src/test/java/org/apache/commons/lang3/math/NumberUtilsIsCreatableTest.java
@@ -0,0 +1,52 @@
+/*
+ * 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 org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class NumberUtilsIsCreatableTest {
+
+    @Test
+    public void testValidIntegers() {
+        assertTrue(NumberUtils.isCreatable("123"));
+        assertTrue(NumberUtils.isCreatable("-456"));
+        assertTrue(NumberUtils.isCreatable("+789"));
+    }
+
+    @Test
+    public void testValidDecimalNumbers() {
+        assertTrue(NumberUtils.isCreatable("123.456"));
+        assertTrue(NumberUtils.isCreatable("-0.001"));
+        assertTrue(NumberUtils.isCreatable(".5"));
+        assertTrue(NumberUtils.isCreatable("5."));
+    }
+
+    @Test
+    public void testScientificNotation() {
+        assertTrue(NumberUtils.isCreatable("1e10"));
+        assertTrue(NumberUtils.isCreatable("-2.5E-3"));
+    }
+
+    @Test
+    public void testHexAndOctal() {
+        assertTrue(NumberUtils.isCreatable("0xFF"));
+        assertTrue(NumberUtils.isCreatable("0Xabc"));
+        assertTrue(NumberUtils.isCreatable("0777")); // treated as octal
+    }
+}
\ No newline at end of file