BAEL-6342 JUnit Test Class for Null and Empty String (#13963)

core-java-modules/core-java-string-apis-2/src/test/java/com/baeldung/nullandempty/NullAndEmptyStringUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.nullandempty;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.Test;
+
+public class NullAndEmptyStringUnitTest {
+
+    @Test
+    void givenANullAndEmptyString_whenUsingStringMethods_thenShouldGetExpectedResult() {
+        String nullString = null;
+        String emptyString = "";
+        assertTrue(emptyString.equals(""));
+        assertThrows(NullPointerException.class, () -> nullString.length());
+    }
+
+    @Test
+    void givenANullAndEmptyString_whenCheckingEquality_thenShouldGetExpectedResult() {
+        String nullString = null;
+        String emptyString = "";
+        assertFalse(emptyString.equals(nullString));
+        assertFalse(emptyString == nullString);
+    }
+
+}