Remove the last character of a Java StringBuilder (#12653)

core-java-modules/core-java-string-apis/src/test/java/com/baeldung/removelastcharfromsb/RemoveLastCharFromSbUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.removelastcharfromsb;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class RemoveLastCharFromSbUnitTest {
+    @Test
+    void givenSb_whenRemovingUsingDeleteCharAt_shouldGetExpectedResult() {
+        StringBuilder sb = new StringBuilder("Using the sb.deleteCharAt() method!");
+        sb.deleteCharAt(sb.length() - 1);
+        assertEquals("Using the sb.deleteCharAt() method", sb.toString());
+    }
+
+    @Test
+    void givenSb_whenRemovingUsingReplace_shouldGetExpectedResult() {
+        StringBuilder sb = new StringBuilder("Using the sb.replace() method!");
+        int last = sb.length() - 1;
+        sb.replace(last, last + 1, "");
+        assertEquals("Using the sb.replace() method", sb.toString());
+    }
+
+    @Test
+    void givenSb_whenRemovingUsingSubString_shouldGetExpectedResult() {
+        StringBuilder sb = new StringBuilder("Using the sb.substring() method!");
+        assertEquals("Using the sb.substring() method", sb.substring(0, sb.length() - 1));
+        //the stringBuilder object is not changed
+        assertEquals("Using the sb.substring() method!", sb.toString());
+    }
+}