Add StringUtilsTest

util/pom.xml

@@ -27,5 +27,9 @@
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+    </dependency>
   </dependencies>
 </project>

util/src/test/java/dev/openrs2/util/StringUtilsTest.java

@@ -0,0 +1,21 @@
+package dev.openrs2.util;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public final class StringUtilsTest {
+	@Test
+	public void testIndefiniteArticle() {
+		assertEquals("a", StringUtils.indefiniteArticle("book"));
+		assertEquals("an", StringUtils.indefiniteArticle("aeroplane"));
+
+		assertThrows(IllegalArgumentException.class, () -> StringUtils.indefiniteArticle(""));
+	}
+
+	@Test
+	public void testCapitalize() {
+		assertEquals("Hello", StringUtils.capitalize("hello"));
+		assertEquals("", StringUtils.capitalize(""));
+	}
+}