--- old/test/jdk/java/time/test/java/time/format/TestDateTimeFormatter.java	2018-04-18 13:12:14.962702500 +0530
+++ new/test/jdk/java/time/test/java/time/format/TestDateTimeFormatter.java	2018-04-18 13:12:12.315173100 +0530
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -93,10 +93,11 @@
 
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
+import static org.testng.Assert.assertEquals;
 
 /**
  * Test DateTimeFormatter.
- * @bug 8085887
+ * @bug 8085887 8193877
  */
 @Test
 public class TestDateTimeFormatter {
@@ -272,4 +273,36 @@
 
     }
 
+    @DataProvider(name = "validPatterns")
+    Object[][] valid_Data() {
+        return new Object[][]{
+                {"pdQ", LocalDate.of(2018, 4, 9), "92"},
+                {"ppdM", LocalDate.of(2018, 4, 9), " 94"},
+                {"dppMyy", LocalDate.of(2018, 4, 9), "9 418"},
+                {"ppHmmss", LocalTime.of(1,20,45), " 12045"},
+                {"pppddMMyyyy", LocalDate.of(2018, 4, 9), " 09042018"},
+                {"ppdppMYYYY", LocalDate.of(2018, 4, 9), " 9 42018"}
+        };
+    }
+
+    @Test(dataProvider="validPatterns")
+    public void test_pattern(String pattern, TemporalAccessor input, String expected) throws Exception {
+        String actual = DateTimeFormatter.ofPattern(pattern).format(input);
+        assertEquals(actual, expected);
+    }
+
+    @DataProvider(name = "invalidPatterns")
+    Object[][] invalid_Data() {
+        return new Object[][]{
+                {"pddQ", LocalDate.of(2018, 4, 9)},
+                {"dpMMyy", LocalDate.of(2018, 4, 9)},
+                {"H:pmmss", LocalTime.of(1,20,45)},
+        };
+    }
+
+    @Test(dataProvider="invalidPatterns", expectedExceptions=DateTimeException.class)
+    public void test_invalidPattern(String pattern, TemporalAccessor input) throws Exception {
+        DateTimeFormatter.ofPattern(pattern).format(input);
+    }
+
 }