Fix typo

testing-modules/parallel-tests-junit/string-test-functions/src/test/java/com/baeldung/StringFunctionUnitTest.java

@@ -0,0 +1,18 @@
+package com.baeldung;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class StringFunctionUnitTest {
+
+    @Test
+    public void test_upperCase() {
+        assertEquals("TESTCASE", "testCase".toUpperCase());
+    }
+
+    @Test
+    public void test_indexOf() {
+        assertEquals(1, "testCase".indexOf("e"));
+    }
+}