diff --git a/core-java-modules/core-java-string-operations-4/src/test/java/com/baeldung/removewhitespace/RemoveWhitespaceUnitTest.java b/core-java-modules/core-java-string-operations-4/src/test/java/com/baeldung/removewhitespace/RemoveWhitespaceUnitTest.java
new file mode 100644
index 0000000000..f749484ba9
--- /dev/null
+++ b/core-java-modules/core-java-string-operations-4/src/test/java/com/baeldung/removewhitespace/RemoveWhitespaceUnitTest.java
@@ -0,0 +1,35 @@
+package com.baeldung.removewhitespace;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class RemoveWhitespaceUnitTest {
+    private final String myString = "   I    am a    wonderful String     !   ";
+
+    @Test
+    void givenStringWithWhitespace_whenRemoveAllWhitespace_shouldGetExpectedResult() {
+        String result = myString.replaceAll("\\s", "");
+        assertThat(result).isEqualTo("IamawonderfulString!");
+    }
+
+    @Test
+    void givenStringWithWhitespace_whenRemoveAllWhitespaceUsingStringUtils_shouldGetExpectedResult() {
+        String result = StringUtils.deleteWhitespace(myString);
+        assertThat(result).isEqualTo("IamawonderfulString!");
+    }
+
+    @Test
+    void givenStringWithWhitespace_whenReplaceConsecutiveSpacesWithSingleSpace_shouldGetExpectedResult() {
+        String result = myString.replaceAll("\\s+", " ");
+        assertThat(result).isEqualTo(" I am a wonderful String ! ");
+        assertThat(result.trim()).isEqualTo("I am a wonderful String !");
+    }
+
+    @Test
+    void givenStringWithWhitespace_whenNormalizeWithApacheCommons_shouldGetExpectedResult() {
+        String result = StringUtils.normalizeSpace(myString);
+        assertThat(result).isEqualTo("I am a wonderful String !");
+    }
+}