1 files changed, 93 insertions, 0 deletions
diff --git a/support/src/test/java/libcore/sun/security/x509/Utils.java b/support/src/test/java/libcore/sun/security/x509/Utils.java
new file mode 100644
index 0000000000..412a06d1a1
--- /dev/null
+++ b/support/src/test/java/libcore/sun/security/x509/Utils.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package libcore.sun.security.x509;
+
+import junit.framework.Assert;
+
+import java.util.function.Function;
+
+public class Utils extends Assert {
+    /**
+     * Many classes in this package can be created using a bit array, and the toString method
+     * depends only on the bit array. The logic for toString was changed in rev/04cda5b7a3c1.
+     * The expected result is the same before and after the change.
+     * @param parts The different parts of the result
+     * @param objectCreator Function to create a new instance of the class tested.
+     * @param prefix prefix in all toString results
+     * @param suffix suffix in all toString results
+     */
+    static void test_toString_bitArrayBasedClass(
+            String[] parts,
+            Function<byte[], Object> objectCreator,
+            String prefix,
+            String suffix) {
+        testWithEachSinglePart(parts, objectCreator, prefix, suffix);
+        testWithAllParts(parts, objectCreator, prefix, suffix);
+        testWithNoParts(parts, objectCreator, prefix, suffix);
+        testWithEveryOtherPart(parts, objectCreator, prefix, suffix);
+    }
+
+    private static void testWithEachSinglePart(
+            String[] parts, Function<byte[], Object> objectCreator, String prefix, String suffix) {
+        int bitCounter = 0, byteCounter = 1;
+        for (int i = 0; i < parts.length; i++) {
+            byte[] ba = new byte[byteCounter];
+            ba[byteCounter - 1] = (byte) (1 << (7 - bitCounter));
+            bitCounter++;
+            if (bitCounter == 8) {
+                bitCounter = 0;
+                byteCounter++;
+            }
+            Object o =  objectCreator.apply(ba);
+            assertEquals(prefix + parts[i] + suffix, o.toString());
+        }
+    }
+
+    private static void testWithAllParts(
+            String[] parts, Function<byte[], Object> objectCreator, String prefix, String suffix) {
+        int bitsInAByte = 8;
+        int allOnesLength = (parts.length + bitsInAByte - 1) / bitsInAByte;
+        byte[] allOnes = new byte[allOnesLength];
+
+        for (int i = 0; i < allOnes.length; i++) {
+            allOnes[i] = -1;
+        }
+        assertEquals(prefix + String.join("", parts)
+                + suffix, objectCreator.apply(allOnes).toString());
+    }
+
+    private static void testWithNoParts(
+            String[] parts, Function<byte[], Object> objectCreator, String prefix, String suffix) {
+        // Test with empty array
+        assertEquals(prefix + suffix, objectCreator.apply(new byte[0]).toString());
+
+        // Test with array will all zeros
+        assertEquals(prefix + suffix, objectCreator.apply(new byte[parts.length]).toString());
+    }
+
+    private static void testWithEveryOtherPart(
+            String[] parts, Function<byte[], Object> objectCreator, String prefix, String suffix) {
+        int bitsInAByte = 8;
+        byte[] ba = new byte[(parts.length + bitsInAByte - 1) / bitsInAByte];
+        String expectedResult = new String();
+        for (int i = 0; i < parts.length; i += 2) {
+            ba[i / bitsInAByte] = (byte) 170; // Binary 10101010
+            expectedResult += parts[i];
+        }
+        assertEquals(prefix + expectedResult + suffix, objectCreator.apply(ba).toString());
+    }
+}