Update //third_party/protobuf to version 3.

third_party/protobuf/java/src/test/java/com/google/protobuf/ByteStringTest.java

Index: third_party/protobuf/java/src/test/java/com/google/protobuf/ByteStringTest.java
diff --git a/third_party/protobuf/java/src/test/java/com/google/protobuf/ByteStringTest.java b/third_party/protobuf/java/src/test/java/com/google/protobuf/ByteStringTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..36f642515ce11b1551b0805851ceb2cf7b85b766
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+++ b/third_party/protobuf/java/src/test/java/com/google/protobuf/ByteStringTest.java
@@ -0,0 +1,760 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import com.google.protobuf.ByteString.Output;
+
+import junit.framework.TestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Random;
+
+/**
+ * Test methods with implementations in {@link ByteString}, plus do some top-level "integration"
+ * tests.
+ *
+ * @author carlanton@google.com (Carl Haverl)
+ */
+public class ByteStringTest extends TestCase {
+
+  private static final Charset UTF_16 = Charset.forName("UTF-16");
+
+  static byte[] getTestBytes(int size, long seed) {
+    Random random = new Random(seed);
+    byte[] result = new byte[size];
+    random.nextBytes(result);
+    return result;
+  }
+
+  private byte[] getTestBytes(int size) {
+    return getTestBytes(size, 445566L);
+  }
+
+  private byte[] getTestBytes() {
+    return getTestBytes(1000);
+  }
+
+  // Compare the entire left array with a subset of the right array.
+  private boolean isArrayRange(byte[] left, byte[] right, int rightOffset, int length) {
+    boolean stillEqual = (left.length == length);
+    for (int i = 0; (stillEqual && i < length); ++i) {
+      stillEqual = (left[i] == right[rightOffset + i]);
+    }
+    return stillEqual;
+  }
+
+  // Returns true only if the given two arrays have identical contents.
+  private boolean isArray(byte[] left, byte[] right) {
+    return left.length == right.length && isArrayRange(left, right, 0, left.length);
+  }
+
+  public void testSubstring_BeginIndex() {
+    byte[] bytes = getTestBytes();
+    ByteString substring = ByteString.copyFrom(bytes).substring(500);
+    assertTrue("substring must contain the tail of the string",
+        isArrayRange(substring.toByteArray(), bytes, 500, bytes.length - 500));
+  }
+
+  public void testCopyFrom_BytesOffsetSize() {
+    byte[] bytes = getTestBytes();
+    ByteString byteString = ByteString.copyFrom(bytes, 500, 200);
+    assertTrue("copyFrom sub-range must contain the expected bytes",
+        isArrayRange(byteString.toByteArray(), bytes, 500, 200));
+  }
+
+  public void testCopyFrom_Bytes() {
+    byte[] bytes = getTestBytes();
+    ByteString byteString = ByteString.copyFrom(bytes);
+    assertTrue("copyFrom must contain the expected bytes",
+        isArray(byteString.toByteArray(), bytes));
+  }
+
+  public void testCopyFrom_ByteBufferSize() {
+    byte[] bytes = getTestBytes();
+    ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
+    byteBuffer.put(bytes);
+    byteBuffer.position(500);
+    ByteString byteString = ByteString.copyFrom(byteBuffer, 200);
+    assertTrue("copyFrom byteBuffer sub-range must contain the expected bytes",
+        isArrayRange(byteString.toByteArray(), bytes, 500, 200));
+  }
+
+  public void testCopyFrom_ByteBuffer() {
+    byte[] bytes = getTestBytes();
+    ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
+    byteBuffer.put(bytes);
+    byteBuffer.position(500);
+    ByteString byteString = ByteString.copyFrom(byteBuffer);
+    assertTrue("copyFrom byteBuffer sub-range must contain the expected bytes",
+        isArrayRange(byteString.toByteArray(), bytes, 500, bytes.length - 500));
+  }
+
+  public void testCopyFrom_StringEncoding() {
+    String testString = "I love unicode \u1234\u5678 characters";
+    ByteString byteString = ByteString.copyFrom(testString, UTF_16);
+    byte[] testBytes = testString.getBytes(UTF_16);
+    assertTrue("copyFrom string must respect the charset",
+        isArrayRange(byteString.toByteArray(), testBytes, 0, testBytes.length));
+  }
+
+  public void testCopyFrom_Utf8() {
+    String testString = "I love unicode \u1234\u5678 characters";
+    ByteString byteString = ByteString.copyFromUtf8(testString);
+    byte[] testBytes = testString.getBytes(Internal.UTF_8);
+    assertTrue("copyFromUtf8 string must respect the charset",
+        isArrayRange(byteString.toByteArray(), testBytes, 0, testBytes.length));
+  }
+
+  public void testCopyFrom_Iterable() {
+    byte[] testBytes = getTestBytes(77777, 113344L);
+    final List<ByteString> pieces = makeConcretePieces(testBytes);
+    // Call copyFrom() on a Collection
+    ByteString byteString = ByteString.copyFrom(pieces);
+    assertTrue("copyFrom a List must contain the expected bytes",
+        isArrayRange(byteString.toByteArray(), testBytes, 0, testBytes.length));
+    // Call copyFrom on an iteration that's not a collection
+    ByteString byteStringAlt = ByteString.copyFrom(new Iterable<ByteString>() {
+      @Override
+      public Iterator<ByteString> iterator() {
+        return pieces.iterator();
+      }
+    });
+    assertEquals("copyFrom from an Iteration must contain the expected bytes",
+        byteString, byteStringAlt);
+  }
+
+  public void testCopyTo_TargetOffset() {
+    byte[] bytes = getTestBytes();
+    ByteString byteString = ByteString.copyFrom(bytes);
+    byte[] target = new byte[bytes.length + 1000];
+    byteString.copyTo(target, 400);
+    assertTrue("copyFrom byteBuffer sub-range must contain the expected bytes",
+        isArrayRange(bytes, target, 400, bytes.length));
+  }
+
+  public void testReadFrom_emptyStream() throws IOException {
+    ByteString byteString =
+        ByteString.readFrom(new ByteArrayInputStream(new byte[0]));
+    assertSame("reading an empty stream must result in the EMPTY constant "
+        + "byte string", ByteString.EMPTY, byteString);
+  }
+
+  public void testReadFrom_smallStream() throws IOException {
+    assertReadFrom(getTestBytes(10));
+  }
+
+  public void testReadFrom_mutating() throws IOException {
+    byte[] capturedArray = null;
+    EvilInputStream eis = new EvilInputStream();
+    ByteString byteString = ByteString.readFrom(eis);
+
+    capturedArray = eis.capturedArray;
+    byte[] originalValue = byteString.toByteArray();
+    for (int x = 0; x < capturedArray.length; ++x) {
+      capturedArray[x] = (byte) 0;
+    }
+
+    byte[] newValue = byteString.toByteArray();
+    assertTrue("copyFrom byteBuffer must not grant access to underlying array",
+        Arrays.equals(originalValue, newValue));
+  }
+
+  // Tests sizes that are near the rope copy-out threshold.
+  public void testReadFrom_mediumStream() throws IOException {
+    assertReadFrom(getTestBytes(ByteString.CONCATENATE_BY_COPY_SIZE - 1));
+    assertReadFrom(getTestBytes(ByteString.CONCATENATE_BY_COPY_SIZE));
+    assertReadFrom(getTestBytes(ByteString.CONCATENATE_BY_COPY_SIZE + 1));
+    assertReadFrom(getTestBytes(200));
+  }
+
+  // Tests sizes that are over multi-segment rope threshold.
+  public void testReadFrom_largeStream() throws IOException {
+    assertReadFrom(getTestBytes(0x100));
+    assertReadFrom(getTestBytes(0x101));
+    assertReadFrom(getTestBytes(0x110));
+    assertReadFrom(getTestBytes(0x1000));
+    assertReadFrom(getTestBytes(0x1001));
+    assertReadFrom(getTestBytes(0x1010));
+    assertReadFrom(getTestBytes(0x10000));
+    assertReadFrom(getTestBytes(0x10001));
+    assertReadFrom(getTestBytes(0x10010));
+  }
+
+  // Tests sizes that are near the read buffer size.
+  public void testReadFrom_byteBoundaries() throws IOException {
+    final int min = ByteString.MIN_READ_FROM_CHUNK_SIZE;
+    final int max = ByteString.MAX_READ_FROM_CHUNK_SIZE;
+
+    assertReadFrom(getTestBytes(min - 1));
+    assertReadFrom(getTestBytes(min));
+    assertReadFrom(getTestBytes(min + 1));
+
+    assertReadFrom(getTestBytes(min * 2 - 1));
+    assertReadFrom(getTestBytes(min * 2));
+    assertReadFrom(getTestBytes(min * 2 + 1));
+
+    assertReadFrom(getTestBytes(min * 4 - 1));
+    assertReadFrom(getTestBytes(min * 4));
+    assertReadFrom(getTestBytes(min * 4 + 1));
+
+    assertReadFrom(getTestBytes(min * 8 - 1));
+    assertReadFrom(getTestBytes(min * 8));
+    assertReadFrom(getTestBytes(min * 8 + 1));
+
+    assertReadFrom(getTestBytes(max - 1));
+    assertReadFrom(getTestBytes(max));
+    assertReadFrom(getTestBytes(max + 1));
+
+    assertReadFrom(getTestBytes(max * 2 - 1));
+    assertReadFrom(getTestBytes(max * 2));
+    assertReadFrom(getTestBytes(max * 2 + 1));
+  }
+
+  // Tests that IOExceptions propagate through ByteString.readFrom().
+  public void testReadFrom_IOExceptions() {
+    try {
+      ByteString.readFrom(new FailStream());
+      fail("readFrom must throw the underlying IOException");
+
+    } catch (IOException e) {
+      assertEquals("readFrom must throw the expected exception",
+                   "synthetic failure", e.getMessage());
+    }
+  }
+
+  // Tests that ByteString.readFrom works with streams that don't
+  // always fill their buffers.
+  public void testReadFrom_reluctantStream() throws IOException {
+    final byte[] data = getTestBytes(0x1000);
+
+    ByteString byteString = ByteString.readFrom(new ReluctantStream(data));
+    assertTrue("readFrom byte stream must contain the expected bytes",
+        isArray(byteString.toByteArray(), data));
+
+    // Same test as above, but with some specific chunk sizes.
+    assertReadFromReluctantStream(data, 100);
+    assertReadFromReluctantStream(data, 248);
+    assertReadFromReluctantStream(data, 249);
+    assertReadFromReluctantStream(data, 250);
+    assertReadFromReluctantStream(data, 251);
+    assertReadFromReluctantStream(data, 0x1000);
+    assertReadFromReluctantStream(data, 0x1001);
+  }
+
+  // Fails unless ByteString.readFrom reads the bytes correctly from a
+  // reluctant stream with the given chunkSize parameter.
+  private void assertReadFromReluctantStream(byte[] bytes, int chunkSize)
+      throws IOException {
+    ByteString b = ByteString.readFrom(new ReluctantStream(bytes), chunkSize);
+    assertTrue("readFrom byte stream must contain the expected bytes",
+        isArray(b.toByteArray(), bytes));
+  }
+
+  // Tests that ByteString.readFrom works with streams that implement
+  // available().
+  public void testReadFrom_available() throws IOException {
+    final byte[] data = getTestBytes(0x1001);
+
+    ByteString byteString = ByteString.readFrom(new AvailableStream(data));
+    assertTrue("readFrom byte stream must contain the expected bytes",
+        isArray(byteString.toByteArray(), data));
+  }
+
+  // Fails unless ByteString.readFrom reads the bytes correctly.
+  private void assertReadFrom(byte[] bytes) throws IOException {
+    ByteString byteString =
+        ByteString.readFrom(new ByteArrayInputStream(bytes));
+    assertTrue("readFrom byte stream must contain the expected bytes",
+        isArray(byteString.toByteArray(), bytes));
+  }
+
+  // A stream that fails when read.
+  private static final class FailStream extends InputStream {
+    @Override public int read() throws IOException {
+      throw new IOException("synthetic failure");
+    }
+  }
+
+  // A stream that simulates blocking by only producing 250 characters
+  // per call to read(byte[]).
+  private static class ReluctantStream extends InputStream {
+    protected final byte[] data;
+    protected int pos = 0;
+
+    public ReluctantStream(byte[] data) {
+      this.data = data;
+    }
+
+    @Override public int read() {
+      if (pos == data.length) {
+        return -1;
+      } else {
+        return data[pos++];
+      }
+    }
+
+    @Override public int read(byte[] buf) {
+      return read(buf, 0, buf.length);
+    }
+
+    @Override public int read(byte[] buf, int offset, int size) {
+      if (pos == data.length) {
+        return -1;
+      }
+      int count = Math.min(Math.min(size, data.length - pos), 250);
+      System.arraycopy(data, pos, buf, offset, count);
+      pos += count;
+      return count;
+    }
+  }
+
+  // Same as above, but also implements available().
+  private static final class AvailableStream extends ReluctantStream {
+    public AvailableStream(byte[] data) {
+      super(data);
+    }
+
+    @Override public int available() {
+      return Math.min(250, data.length - pos);
+    }
+  }
+
+  // A stream which exposes the byte array passed into read(byte[], int, int).
+  private static class EvilInputStream extends InputStream {
+    public byte[] capturedArray = null;
+
+    @Override
+    public int read(byte[] buf, int off, int len) {
+      if (capturedArray != null) {
+        return -1;
+      } else {
+        capturedArray = buf;
+        for (int x = 0; x < len; ++x) {
+          buf[x] = (byte) x;
+        }
+        return len;
+      }
+    }
+
+    @Override
+    public int read() {
+      // Purposefully do nothing.
+      return -1;
+    }
+  }
+
+  // A stream which exposes the byte array passed into write(byte[], int, int).
+  private static class EvilOutputStream extends OutputStream {
+    public byte[] capturedArray = null;
+
+    @Override
+    public void write(byte[] buf, int off, int len) {
+      if (capturedArray == null) {
+        capturedArray = buf;
+      }
+    }
+
+    @Override
+    public void write(int ignored) {
+      // Purposefully do nothing.
+    }
+  }
+
+  public void testToStringUtf8() {
+    String testString = "I love unicode \u1234\u5678 characters";
+    byte[] testBytes = testString.getBytes(Internal.UTF_8);
+    ByteString byteString = ByteString.copyFrom(testBytes);
+    assertEquals("copyToStringUtf8 must respect the charset",
+        testString, byteString.toStringUtf8());
+  }
+
+  public void testNewOutput_InitialCapacity() throws IOException {
+    byte[] bytes = getTestBytes();
+    ByteString.Output output = ByteString.newOutput(bytes.length + 100);
+    output.write(bytes);
+    ByteString byteString = output.toByteString();
+    assertTrue(
+        "String built from newOutput(int) must contain the expected bytes",
+        isArrayRange(bytes, byteString.toByteArray(), 0, bytes.length));
+  }
+
+  // Test newOutput() using a variety of buffer sizes and a variety of (fixed)
+  // write sizes
+  public void testNewOutput_ArrayWrite() {
+    byte[] bytes = getTestBytes();
+    int length = bytes.length;
+    int[] bufferSizes = {128, 256, length / 2, length - 1, length, length + 1,
+                         2 * length, 3 * length};
+    int[] writeSizes = {1, 4, 5, 7, 23, bytes.length};
+
+    for (int bufferSize : bufferSizes) {
+      for (int writeSize : writeSizes) {
+        // Test writing the entire output writeSize bytes at a time.
+        ByteString.Output output = ByteString.newOutput(bufferSize);
+        for (int i = 0; i < length; i += writeSize) {
+          output.write(bytes, i, Math.min(writeSize, length - i));
+        }
+        ByteString byteString = output.toByteString();
+        assertTrue("String built from newOutput() must contain the expected bytes",
+            isArrayRange(bytes, byteString.toByteArray(), 0, bytes.length));
+      }
+    }
+  }
+
+  // Test newOutput() using a variety of buffer sizes, but writing all the
+  // characters using write(byte);
+  public void testNewOutput_WriteChar() {
+    byte[] bytes = getTestBytes();
+    int length = bytes.length;
+    int[] bufferSizes = {0, 1, 128, 256, length / 2,
+                         length - 1, length, length + 1,
+                         2 * length, 3 * length};
+    for (int bufferSize : bufferSizes) {
+      ByteString.Output output = ByteString.newOutput(bufferSize);
+      for (byte byteValue : bytes) {
+        output.write(byteValue);
+      }
+      ByteString byteString = output.toByteString();
+      assertTrue("String built from newOutput() must contain the expected bytes",
+          isArrayRange(bytes, byteString.toByteArray(), 0, bytes.length));
+    }
+  }
+
+  // Test newOutput() in which we write the bytes using a variety of methods
+  // and sizes, and in which we repeatedly call toByteString() in the middle.
+  public void testNewOutput_Mixed() {
+    Random rng = new Random(1);
+    byte[] bytes = getTestBytes();
+    int length = bytes.length;
+    int[] bufferSizes = {0, 1, 128, 256, length / 2,
+                         length - 1, length, length + 1,
+                         2 * length, 3 * length};
+
+    for (int bufferSize : bufferSizes) {
+      // Test writing the entire output using a mixture of write sizes and
+      // methods;
+      ByteString.Output output = ByteString.newOutput(bufferSize);
+      int position = 0;
+      while (position < bytes.length) {
+        if (rng.nextBoolean()) {
+          int count = 1 + rng.nextInt(bytes.length - position);
+          output.write(bytes, position, count);
+          position += count;
+        } else {
+          output.write(bytes[position]);
+          position++;
+        }
+        assertEquals("size() returns the right value", position, output.size());
+        assertTrue("newOutput() substring must have correct bytes",
+            isArrayRange(output.toByteString().toByteArray(),
+                bytes, 0, position));
+      }
+      ByteString byteString = output.toByteString();
+      assertTrue("String built from newOutput() must contain the expected bytes",
+          isArrayRange(bytes, byteString.toByteArray(), 0, bytes.length));
+    }
+  }
+
+  public void testNewOutputEmpty() {
+    // Make sure newOutput() correctly builds empty byte strings
+    ByteString byteString = ByteString.newOutput().toByteString();
+    assertEquals(ByteString.EMPTY, byteString);
+  }
+
+  public void testNewOutput_Mutating() throws IOException {
+    Output os = ByteString.newOutput(5);
+    os.write(new byte[] {1, 2, 3, 4, 5});
+    EvilOutputStream eos = new EvilOutputStream();
+    os.writeTo(eos);
+    byte[] capturedArray = eos.capturedArray;
+    ByteString byteString = os.toByteString();
+    byte[] oldValue = byteString.toByteArray();
+    Arrays.fill(capturedArray, (byte) 0);
+    byte[] newValue = byteString.toByteArray();
+    assertTrue("Output must not provide access to the underlying byte array",
+        Arrays.equals(oldValue, newValue));
+  }
+
+  public void testNewCodedBuilder() throws IOException {
+    byte[] bytes = getTestBytes();
+    ByteString.CodedBuilder builder = ByteString.newCodedBuilder(bytes.length);
+    builder.getCodedOutput().writeRawBytes(bytes);
+    ByteString byteString = builder.build();
+    assertTrue("String built from newCodedBuilder() must contain the expected bytes",
+        isArrayRange(bytes, byteString.toByteArray(), 0, bytes.length));
+  }
+
+  public void testSubstringParity() {
+    byte[] bigBytes = getTestBytes(2048 * 1024, 113344L);
+    int start = 512 * 1024 - 3333;
+    int end   = 512 * 1024 + 7777;
+    ByteString concreteSubstring = ByteString.copyFrom(bigBytes).substring(start, end);
+    boolean ok = true;
+    for (int i = start; ok && i < end; ++i) {
+      ok = (bigBytes[i] == concreteSubstring.byteAt(i - start));
+    }
+    assertTrue("Concrete substring didn't capture the right bytes", ok);
+
+    ByteString literalString = ByteString.copyFrom(bigBytes, start, end - start);
+    assertTrue("Substring must be equal to literal string",
+        concreteSubstring.equals(literalString));
+    assertEquals("Substring must have same hashcode as literal string",
+        literalString.hashCode(), concreteSubstring.hashCode());
+  }
+
+  public void testCompositeSubstring() {
+    byte[] referenceBytes = getTestBytes(77748, 113344L);
+
+    List<ByteString> pieces = makeConcretePieces(referenceBytes);
+    ByteString listString = ByteString.copyFrom(pieces);
+
+    int from = 1000;
+    int to = 40000;
+    ByteString compositeSubstring = listString.substring(from, to);
+    byte[] substringBytes = compositeSubstring.toByteArray();
+    boolean stillEqual = true;
+    for (int i = 0; stillEqual && i < to - from; ++i) {
+      stillEqual = referenceBytes[from + i] == substringBytes[i];
+    }
+    assertTrue("Substring must return correct bytes", stillEqual);
+
+    stillEqual = true;
+    for (int i = 0; stillEqual && i < to - from; ++i) {
+      stillEqual = referenceBytes[from + i] == compositeSubstring.byteAt(i);
+    }
+    assertTrue("Substring must support byteAt() correctly", stillEqual);
+
+    ByteString literalSubstring = ByteString.copyFrom(referenceBytes, from, to - from);
+    assertTrue("Composite substring must equal a literal substring over the same bytes",
+        compositeSubstring.equals(literalSubstring));
+    assertTrue("Literal substring must equal a composite substring over the same bytes",
+        literalSubstring.equals(compositeSubstring));
+
+    assertEquals("We must get the same hashcodes for composite and literal substrings",
+        literalSubstring.hashCode(), compositeSubstring.hashCode());
+
+    assertFalse("We can't be equal to a proper substring",
+        compositeSubstring.equals(literalSubstring.substring(0, literalSubstring.size() - 1)));
+  }
+
+  public void testCopyFromList() {
+    byte[] referenceBytes = getTestBytes(77748, 113344L);
+    ByteString literalString = ByteString.copyFrom(referenceBytes);
+
+    List<ByteString> pieces = makeConcretePieces(referenceBytes);
+    ByteString listString = ByteString.copyFrom(pieces);
+
+    assertTrue("Composite string must be equal to literal string",
+        listString.equals(literalString));
+    assertEquals("Composite string must have same hashcode as literal string",
+        literalString.hashCode(), listString.hashCode());
+  }
+
+  public void testConcat() {
+    byte[] referenceBytes = getTestBytes(77748, 113344L);
+    ByteString literalString = ByteString.copyFrom(referenceBytes);
+
+    List<ByteString> pieces = makeConcretePieces(referenceBytes);
+
+    Iterator<ByteString> iter = pieces.iterator();
+    ByteString concatenatedString = iter.next();
+    while (iter.hasNext()) {
+      concatenatedString = concatenatedString.concat(iter.next());
+    }
+
+    assertTrue("Concatenated string must be equal to literal string",
+        concatenatedString.equals(literalString));
+    assertEquals("Concatenated string must have same hashcode as literal string",
+        literalString.hashCode(), concatenatedString.hashCode());
+  }
+
+  /**
+   * Test the Rope implementation can deal with Empty nodes, even though we
+   * guard against them. See also {@link LiteralByteStringTest#testConcat_empty()}.
+   */
+  public void testConcat_empty() {
+    byte[] referenceBytes = getTestBytes(7748, 113344L);
+    ByteString literalString = ByteString.copyFrom(referenceBytes);
+
+    ByteString duo = RopeByteString.newInstanceForTest(literalString, literalString);
+    ByteString temp = RopeByteString.newInstanceForTest(
+        RopeByteString.newInstanceForTest(literalString, ByteString.EMPTY),
+        RopeByteString.newInstanceForTest(ByteString.EMPTY, literalString));
+    ByteString quintet = RopeByteString.newInstanceForTest(temp, ByteString.EMPTY);
+
+    assertTrue("String with concatenated nulls must equal simple concatenate",
+        duo.equals(quintet));
+    assertEquals("String with concatenated nulls have same hashcode as simple concatenate",
+        duo.hashCode(), quintet.hashCode());
+
+    ByteString.ByteIterator duoIter = duo.iterator();
+    ByteString.ByteIterator quintetIter = quintet.iterator();
+    boolean stillEqual = true;
+    while (stillEqual && quintetIter.hasNext()) {
+      stillEqual = (duoIter.nextByte() == quintetIter.nextByte());
+    }
+    assertTrue("We must get the same characters by iterating", stillEqual);
+    assertFalse("Iterator must be exhausted", duoIter.hasNext());
+    try {
+      duoIter.nextByte();
+      fail("Should have thrown an exception.");
+    } catch (NoSuchElementException e) {
+      // This is success
+    }
+    try {
+      quintetIter.nextByte();
+      fail("Should have thrown an exception.");
+    } catch (NoSuchElementException e) {
+      // This is success
+    }
+
+    // Test that even if we force empty strings in as rope leaves in this
+    // configuration, we always get a (possibly Bounded) LiteralByteString
+    // for a length 1 substring.
+    //
+    // It is possible, using the testing factory method to create deeply nested
+    // trees of empty leaves, to make a string that will fail this test.
+    for (int i = 1; i < duo.size(); ++i) {
+      assertTrue("Substrings of size() < 2 must not be RopeByteStrings",
+          duo.substring(i - 1, i) instanceof LiteralByteString);
+    }
+    for (int i = 1; i < quintet.size(); ++i) {
+      assertTrue("Substrings of size() < 2 must not be RopeByteStrings",
+          quintet.substring(i - 1, i) instanceof LiteralByteString);
+    }
+  }
+
+  public void testStartsWith() {
+    byte[] bytes = getTestBytes(1000, 1234L);
+    ByteString string = ByteString.copyFrom(bytes);
+    ByteString prefix = ByteString.copyFrom(bytes, 0, 500);
+    ByteString suffix = ByteString.copyFrom(bytes, 400, 600);
+    assertTrue(string.startsWith(ByteString.EMPTY));
+    assertTrue(string.startsWith(string));
+    assertTrue(string.startsWith(prefix));
+    assertFalse(string.startsWith(suffix));
+    assertFalse(prefix.startsWith(suffix));
+    assertFalse(suffix.startsWith(prefix));
+    assertFalse(ByteString.EMPTY.startsWith(prefix));
+    assertTrue(ByteString.EMPTY.startsWith(ByteString.EMPTY));
+  }
+
+  public void testEndsWith() {
+    byte[] bytes = getTestBytes(1000, 1234L);
+    ByteString string = ByteString.copyFrom(bytes);
+    ByteString prefix = ByteString.copyFrom(bytes, 0, 500);
+    ByteString suffix = ByteString.copyFrom(bytes, 400, 600);
+    assertTrue(string.endsWith(ByteString.EMPTY));
+    assertTrue(string.endsWith(string));
+    assertTrue(string.endsWith(suffix));
+    assertFalse(string.endsWith(prefix));
+    assertFalse(suffix.endsWith(prefix));
+    assertFalse(prefix.endsWith(suffix));
+    assertFalse(ByteString.EMPTY.endsWith(suffix));
+    assertTrue(ByteString.EMPTY.endsWith(ByteString.EMPTY));
+  }
+
+  static List<ByteString> makeConcretePieces(byte[] referenceBytes) {
+    List<ByteString> pieces = new ArrayList<ByteString>();
+    // Starting length should be small enough that we'll do some concatenating by
+    // copying if we just concatenate all these pieces together.
+    for (int start = 0, length = 16; start < referenceBytes.length; start += length) {
+      length = (length << 1) - 1;
+      if (start + length > referenceBytes.length) {
+        length = referenceBytes.length - start;
+      }
+      pieces.add(ByteString.copyFrom(referenceBytes, start, length));
+    }
+    return pieces;
+  }
+
+  private byte[] substringUsingWriteTo(
+      ByteString data, int offset, int length) throws IOException {
+    ByteArrayOutputStream output = new ByteArrayOutputStream();
+    data.writeTo(output, offset, length);
+    return output.toByteArray();
+  }
+
+  public void testWriteToOutputStream() throws Exception {
+    // Choose a size large enough so when two ByteStrings are concatenated they
+    // won't be merged into one byte array due to some optimizations.
+    final int dataSize = ByteString.CONCATENATE_BY_COPY_SIZE + 1;
+    byte[] data1 = new byte[dataSize];
+    for (int i = 0; i < data1.length; i++) {
+      data1[i] = (byte) 1;
+    }
+    data1[1] = (byte) 11;
+    // Test LiteralByteString.writeTo(OutputStream,int,int)
+    LiteralByteString left = new LiteralByteString(data1);
+    byte[] result = substringUsingWriteTo(left, 1, 1);
+    assertEquals(1, result.length);
+    assertEquals((byte) 11, result[0]);
+
+    byte[] data2 = new byte[dataSize];
+    for (int i = 0; i < data1.length; i++) {
+      data2[i] = (byte) 2;
+    }
+    LiteralByteString right = new LiteralByteString(data2);
+    // Concatenate two ByteStrings to create a RopeByteString.
+    ByteString root = left.concat(right);
+    // Make sure we are actually testing a RopeByteString with a simple tree
+    // structure.
+    assertEquals(1, root.getTreeDepth());
+    // Write parts of the left node.
+    result = substringUsingWriteTo(root, 0, dataSize);
+    assertEquals(dataSize, result.length);
+    assertEquals((byte) 1, result[0]);
+    assertEquals((byte) 1, result[dataSize - 1]);
+    // Write parts of the right node.
+    result = substringUsingWriteTo(root, dataSize, dataSize);
+    assertEquals(dataSize, result.length);
+    assertEquals((byte) 2, result[0]);
+    assertEquals((byte) 2, result[dataSize - 1]);
+    // Write a segment of bytes that runs across both nodes.
+    result = substringUsingWriteTo(root, dataSize / 2, dataSize);
+    assertEquals(dataSize, result.length);
+    assertEquals((byte) 1, result[0]);
+    assertEquals((byte) 1, result[dataSize - dataSize / 2 - 1]);
+    assertEquals((byte) 2, result[dataSize - dataSize / 2]);
+    assertEquals((byte) 2, result[dataSize - 1]);
+  }
+}