--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/lang/String/Indent.java	Wed Jan 09 22:59:49 2019 +0100
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @summary Unit tests for String#indent
+ * @run main Indent
+ */
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class Indent {
+    static final List<String> ENDS = List.of("", "\n", "   \n", "\n\n", "\n\n\n");
+    static final List<String> MIDDLES = List.of(
+            "",
+            "xyz",
+            "   xyz",
+            "      xyz",
+            "xyz   ",
+            "   xyz   ",
+            "      xyz   ",
+            "xyz\u2022",
+            "   xyz\u2022",
+            "xyz\u2022   ",
+            "   xyz\u2022   ",
+            "   // comment"
+    );
+
+    public static void main(String[] args) {
+        test1();
+    }
+
+    /*
+     * Test String#indent(int n) functionality.
+     */
+    static void test1() {
+        for (int adjust : new int[] {-8, -7, -4, -3, -2, -1, 0, 1, 2, 3, 4, 7, 8}) {
+            for (String prefix : ENDS) {
+                for (String suffix : ENDS) {
+                    for (String middle : MIDDLES) {
+                        String input = prefix + "   abc   \n" + middle + "\n   def   \n" + suffix;
+                        String output = input.indent(adjust);
+
+                        Stream<String> stream = input.lines();
+                        if (adjust > 0) {
+                            final String spaces = " ".repeat(adjust);
+                            stream = stream.map(s -> s.isBlank() ? s : spaces + s);
+                        } else if (adjust < 0) {
+                            stream = stream.map(s -> s.substring(Math.min(-adjust, indexOfNonWhitespace(s))));
+                        }
+                        String expected = stream.collect(Collectors.joining("\n", "", "\n"));
+
+                        if (!output.equals(expected)) {
+                            report("String::indent(int n)",
+                                    "Result indentation not as expected", expected, output);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    public static int indexOfNonWhitespace(String s) {
+        int left = 0;
+        while (left < s.length()) {
+            char ch = s.charAt(left);
+            if (ch != ' ' && ch != '\t' && !Character.isWhitespace(ch)) {
+                break;
+            }
+            left++;
+        }
+        return left;
+    }
+
+
+    private static String[] getBody(String[] inLines) {
+        int from = -1, to = -1;
+        for (int i = 0; i < inLines.length; i++) {
+            String line = inLines[i];
+            if (!line.isBlank()) {
+                if (from == -1) {
+                    from = i;
+                }
+                to = i + 1;
+            }
+        }
+        return Arrays.copyOfRange(inLines, from, to);
+    }
+
+    /*
+     * Report difference in result.
+     */
+    static void report(String test, String message, String input, String output) {
+        System.err.println("Testing " + test + ": " + message);
+        System.err.println();
+        System.err.println("Input: length = " + input.length());
+        System.err.println("_".repeat(40));
+        System.err.print(input.replaceAll(" ", "."));
+        System.err.println("_".repeat(40));
+        System.err.println();
+        System.err.println("Output: length = " + output.length());
+        System.err.println("_".repeat(40));
+        System.err.print(output.replaceAll(" ", "."));
+        System.err.println("_".repeat(40));
+        throw new RuntimeException();
+    }
+}