add test

hutool-core/src/main/java/cn/hutool/core/util/StrUtil.java

@@ -2709,7 +2709,6 @@ public class StrUtil {
 
 	/**
 	 * 有序的格式化文本，使用{number}做为占位符<br>
-	 * 例：<br>
 	 * 通常使用：format("this is {0} for {1}", "a", "b") =》 this is a for b<br>
 	 *
 	 * @param pattern   文本格式

hutool-core/src/test/java/cn/hutool/core/util/StrUtilTest.java

@@ -465,4 +465,10 @@ public class StrUtilTest {
 		Assert.assertTrue(StrUtil.startWith(a, b));
 		Assert.assertFalse(StrUtil.startWithIgnoreEquals(a, b));
 	}
+
+	@Test
+	public void indexedFormatTest() {
+		final String ret = StrUtil.indexedFormat("this is {0} for {1}", "a", 1000);
+		Assert.assertEquals("this is a for 1,000", ret);
+	}
 }