BoundedInputStreamTest.java

// Copyright 2010-2011 James Roper
//
// 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 de.undercouch.bson4jackson.io;

import static org.junit.Assert.assertEquals;

import java.io.ByteArrayInputStream;

import org.junit.Test;

/**
 * Tests for {@link BoundedInputStream}
 * @author James Roper
 */
public class BoundedInputStreamTest {

	private byte[] bytes = new byte[] { 10, 20, 30, 40 };

	@Test
	public void testReadWhenBoundSmaller() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 3);
		try {
			assertEquals(10, is.read());
			assertEquals(20, is.read());
			assertEquals(30, is.read());
			assertEquals(-1, is.read());
			assertEquals(-1, is.read());
			assertEquals(40, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testReadWhenBoundLarger() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 5);
		try {
			assertEquals(10, is.read());
			assertEquals(20, is.read());
			assertEquals(30, is.read());
			assertEquals(40, is.read());
			assertEquals(-1, is.read());
			assertEquals(-1, is.read());
			assertEquals(-1, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testReadLargeBufferWhenBoundSmaller() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 3);
		try {
			byte[] buf = new byte[10];
			assertEquals(3, is.read(buf));
			assertArrayEquals(bytes, buf, 0, 3);
			assertEquals(-1, is.read(buf));
			assertEquals(40, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testReadSmallBufferWhenBoundSmaller() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 3);
		try {
			byte[] buf = new byte[2];
			assertEquals(2, is.read(buf));
			assertArrayEquals(bytes, buf, 0, 2);
			assertEquals(1, is.read(buf));
			assertArrayEquals(bytes, buf, 2, 1);
			assertEquals(-1, is.read(buf));
			assertEquals(40, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testReadLargeBufferWhenBoundLarger() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 5);
		try {
			byte[] buf = new byte[10];
			assertEquals(4, is.read(buf));
			assertArrayEquals(bytes, buf, 0, 4);
			assertEquals(-1, is.read(buf));
			assertEquals(-1, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testReadSmallBufferWhenBoundLarger() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
		BoundedInputStream is = new BoundedInputStream(bais, 5);
		try {
			byte[] buf = new byte[2];
			assertEquals(2, is.read(buf));
			assertArrayEquals(bytes, buf, 0, 2);
			assertEquals(2, is.read(buf));
			assertArrayEquals(bytes, buf, 2, 2);
			assertEquals(-1, is.read(buf));
			assertEquals(-1, bais.read());
		} finally {
			is.close();
		}
	}

	@Test
	public void testLessBytesThanRequestedRead() throws Exception {
		ByteArrayInputStream bais = new ByteArrayInputStream(bytes) {
			@Override
			public int read(byte[] b, int off, int len) {
				if (len > 2) {
					return super.read(b, off, len - 1);
				} else {
					return super.read(b, off, len);
				}
			}
		};
		BoundedInputStream is = new BoundedInputStream(bais, 4);
		try {
			byte[] buf = new byte[3];
			assertEquals(2, is.read(buf));
			assertArrayEquals(bytes, buf, 0, 2);
			assertEquals(2, is.read(buf));
			assertArrayEquals(bytes, buf, 2, 2);
			assertEquals(-1, is.read(buf));
			assertEquals(-1, bais.read());
		} finally {
			is.close();
		}
	}

	private static void assertArrayEquals(byte[] expected, byte[] actual, int off, int len) {
		for (int i = 0; i < len; i++) {
			assertEquals("element [" + i + "] not matching", expected[i + off], actual[i]);
		}
	}
}