UnionInputStreamTest

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package org.eclipse.jgit.util.io;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

import org.junit.Test;

public class UnionInputStreamTest {
	@Test
	public void testEmptyStream() throws IOException {
		try (UnionInputStream u = new UnionInputStream()) {
			assertTrue(u.isEmpty());
			assertEquals(-1, u.read());
			assertEquals(-1, u.read(new byte[1], 0, 1));
			assertEquals(0, u.available());
			assertEquals(0, u.skip(1));
		}
	}

	@Test
	public void testReadSingleBytes() throws IOException {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream();

		assertTrue(u.isEmpty());
		u.add(new ByteArrayInputStream(new byte[] { 1, 0, 2 }));
		u.add(new ByteArrayInputStream(new byte[] { 3 }));
		u.add(new ByteArrayInputStream(new byte[] { 4, 5 }));

		assertFalse(u.isEmpty());
		assertEquals(3, u.available());
		assertEquals(1, u.read());
		assertEquals(0, u.read());
		assertEquals(2, u.read());
		assertEquals(0, u.available());

		assertEquals(3, u.read());
		assertEquals(0, u.available());

		assertEquals(4, u.read());
		assertEquals(1, u.available());
		assertEquals(5, u.read());
		assertEquals(0, u.available());
		assertEquals(-1, u.read());

		assertTrue(u.isEmpty());
		u.add(new ByteArrayInputStream(new byte[] { (byte) 255 }));
		assertEquals(255, u.read());
		assertEquals(-1, u.read());
		assertTrue(u.isEmpty());
	}

	@Test
	public void testReadByteBlocks() throws IOException {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream();
		u.add(new ByteArrayInputStream(new byte[] { 1, 0, 2 }));
		u.add(new ByteArrayInputStream(new byte[] { 3 }));
		u.add(new ByteArrayInputStream(new byte[] { 4, 5 }));

		final byte[] r = new byte[5];
		assertEquals(3, u.read(r, 0, 5));
		assertTrue(Arrays.equals(new byte[] { 1, 0, 2, }, slice(r, 3)));
		assertEquals(1, u.read(r, 0, 5));
		assertEquals(3, r[0]);
		assertEquals(2, u.read(r, 0, 5));
		assertTrue(Arrays.equals(new byte[] { 4, 5, }, slice(r, 2)));
		assertEquals(-1, u.read(r, 0, 5));
	}

	private static byte[] slice(byte[] in, int len) {
		byte[] r = new byte[len];
		System.arraycopy(in, 0, r, 0, len);
		return r;
	}

	@Test
	public void testArrayConstructor() throws IOException {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream(
				new ByteArrayInputStream(new byte[] { 1, 0, 2 }),
				new ByteArrayInputStream(new byte[] { 3 }),
				new ByteArrayInputStream(new byte[] { 4, 5 }));

		final byte[] r = new byte[5];
		assertEquals(3, u.read(r, 0, 5));
		assertTrue(Arrays.equals(new byte[] { 1, 0, 2, }, slice(r, 3)));
		assertEquals(1, u.read(r, 0, 5));
		assertEquals(3, r[0]);
		assertEquals(2, u.read(r, 0, 5));
		assertTrue(Arrays.equals(new byte[] { 4, 5, }, slice(r, 2)));
		assertEquals(-1, u.read(r, 0, 5));
	}

	@Test
	public void testMarkSupported() {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream();
		assertFalse(u.markSupported());
		u.add(new ByteArrayInputStream(new byte[] { 1, 0, 2 }));
		assertFalse(u.markSupported());
	}

	@Test
	public void testSkip() throws IOException {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream();
		u.add(new ByteArrayInputStream(new byte[] { 1, 0, 2 }));
		u.add(new ByteArrayInputStream(new byte[] { 3 }));
		u.add(new ByteArrayInputStream(new byte[] { 4, 5 }));
		assertEquals(0, u.skip(0));
		assertEquals(3, u.skip(3));
		assertEquals(3, u.read());
		assertEquals(2, u.skip(5));
		assertEquals(0, u.skip(5));
		assertEquals(-1, u.read());

		u.add(new ByteArrayInputStream(new byte[] { 20, 30 }) {
			@Override
			public long skip(long n) {
				return 0;
			}
		});
		assertEquals(2, u.skip(8));
		assertEquals(-1, u.read());
	}

	@Test
	public void testAutoCloseDuringRead() throws IOException {
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream();
		final boolean closed[] = new boolean[2];
		u.add(new ByteArrayInputStream(new byte[] { 1 }) {
			@Override
			public void close() {
				closed[0] = true;
			}
		});
		u.add(new ByteArrayInputStream(new byte[] { 2 }) {
			@Override
			public void close() {
				closed[1] = true;
			}
		});

		assertFalse(closed[0]);
		assertFalse(closed[1]);

		assertEquals(1, u.read());
		assertFalse(closed[0]);
		assertFalse(closed[1]);

		assertEquals(2, u.read());
		assertTrue(closed[0]);
		assertFalse(closed[1]);

		assertEquals(-1, u.read());
		assertTrue(closed[0]);
		assertTrue(closed[1]);
	}

	@Test
	public void testCloseDuringClose() throws IOException {
		final boolean closed[] = new boolean[2];
		try (UnionInputStream u = new UnionInputStream()) {
			u.add(new ByteArrayInputStream(new byte[] { 1 }) {
				@Override
				public void close() {
					closed[0] = true;
				}
			});
			u.add(new ByteArrayInputStream(new byte[] { 2 }) {
				@Override
				public void close() {
					closed[1] = true;
				}
			});

			assertFalse(closed[0]);
			assertFalse(closed[1]);
		}

		assertTrue(closed[0]);
		assertTrue(closed[1]);
	}

	@Test
	public void testExceptionDuringClose() {
		@SuppressWarnings("resource") // We are testing the close() method
		final UnionInputStream u = new UnionInputStream();
		u.add(new ByteArrayInputStream(new byte[] { 1 }) {
			@Override
			public void close() throws IOException {
				throw new IOException("I AM A TEST");
			}
		});
		try {
			u.close();
			fail("close ignored inner stream exception");
		} catch (IOException e) {
			assertEquals("I AM A TEST", e.getMessage());
		}
	}

	@Test
	public void testNonBlockingPartialRead() throws Exception {
		InputStream errorReadStream = new InputStream() {
			@Override
			public int read() throws IOException {
				throw new IOException("Expected");
			}
		};
		@SuppressWarnings("resource" /* java 7 */)
		final UnionInputStream u = new UnionInputStream(
				new ByteArrayInputStream(new byte[]{1,2,3}),
				errorReadStream);
		byte buf[] = new byte[10];
		assertEquals(3, u.read(buf, 0, 10));
		assertTrue(Arrays.equals(new byte[] {1,2,3}, slice(buf, 3)));
		try {
			u.read(buf, 0, 1);
			fail("Expected exception from errorReadStream");
		} catch (IOException e) {
			assertEquals("Expected", e.getMessage());
		}
	}
}