Improve test coverage of AutoCRLF(In|Out)putStream

Bug: 405672
Change-Id: I3894e98617fcee16dc2ac9853c203c62eb30c3ab
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/util/io/AutoCRLFInputStreamTest.java

@@ -64,6 +64,17 @@ public class AutoCRLFInputStreamTest {
 		assertNoCrLf("\r\n\r\r", "\r\n\r\r");
 		assertNoCrLf("\r\n\r\n", "\r\n\r\n");
 		assertNoCrLf("\r\n\r\n\r", "\n\r\n\r");
+		assertNoCrLf("\0\n", "\0\n");
+	}
+
+	@Test
+	public void testBoundary() throws IOException {
+		for (int i = AutoCRLFInputStream.BUFFER_SIZE - 10; i < AutoCRLFInputStream.BUFFER_SIZE + 10; i++) {
+			String s1 = AutoCRLFOutputStreamTest.repeat("a", i);
+			assertNoCrLf(s1, s1);
+			String s2 = AutoCRLFOutputStreamTest.repeat("\0", i);
+			assertNoCrLf(s2, s2);
+		}
 	}
 
 	private void assertNoCrLf(String string, String string2) throws IOException {

org.eclipse.jgit.test/tst/org/eclipse/jgit/util/io/AutoCRLFOutputStreamTest.java

@@ -66,29 +66,25 @@ public class AutoCRLFOutputStreamTest {
 		assertNoCrLf("\r\n\r\r", "\r\n\r\r");
 		assertNoCrLf("\r\n\r\n", "\r\n\r\n");
 		assertNoCrLf("\r\n\r\n\r", "\n\r\n\r");
+		assertNoCrLf("\0\n", "\0\n");
 	}
 
 	@Test
 	public void testBoundary() throws IOException {
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE - 5);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE - 4);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE - 3);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE - 2);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE - 1);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE + 1);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE + 2);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE + 3);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE + 4);
-		assertBoundaryCorrect(AutoCRLFOutputStream.BUFFER_SIZE + 5);
+		for (int i = AutoCRLFOutputStream.BUFFER_SIZE - 10; i < AutoCRLFOutputStream.BUFFER_SIZE + 10; i++) {
+			String s1 = repeat("a", i);
+			assertNoCrLf(s1, s1);
+			String s2 = repeat("\0", i);
+			assertNoCrLf(s2, s2);
+		}
 	}
 
-	private void assertBoundaryCorrect(int size) throws IOException {
-		StringBuilder sb = new StringBuilder(size);
+	public static String repeat(String input, int size) {
+		StringBuilder sb = new StringBuilder(input.length() * size);
 		for (int i = 0; i < size; i++)
-			sb.append('a');
+			sb.append(input);
 		String s = sb.toString();
-		assertNoCrLf(s, s);
+		return s;
 	}
 
 	private void assertNoCrLf(String string, String string2) throws IOException {
@@ -105,8 +101,9 @@ public class AutoCRLFOutputStreamTest {
 			throws IOException {
 		byte[] inbytes = input.getBytes();
 		byte[] expectBytes = expect.getBytes();
-		for (int i = 0; i < 5; ++i) {
-			byte[] buf = new byte[i];
+		for (int i = -4; i < 5; ++i) {
+			int size = Math.abs(i);
+			byte[] buf = new byte[size];
 			InputStream in = new ByteArrayInputStream(inbytes);
 			ByteArrayOutputStream bos = new ByteArrayOutputStream();
 			OutputStream out = new AutoCRLFOutputStream(bos);
@@ -115,6 +112,13 @@ public class AutoCRLFOutputStreamTest {
 				while ((n = in.read(buf)) >= 0) {
 					out.write(buf, 0, n);
 				}
+			} else if (i < 0) {
+				int n;
+				while ((n = in.read(buf)) >= 0) {
+					byte[] b = new byte[n];
+					System.arraycopy(buf, 0, b, 0, n);
+					out.write(b);
+				}
 			} else {
 				int c;
 				while ((c = in.read()) != -1)
@@ -124,7 +128,7 @@ public class AutoCRLFOutputStreamTest {
 			in.close();
 			out.close();
 			byte[] actualBytes = bos.toByteArray();
-			Assert.assertEquals("bufsize=" + i, encode(expectBytes),
+			Assert.assertEquals("bufsize=" + size, encode(expectBytes),
 					encode(actualBytes));
 		}
 	}

org.eclipse.jgit/src/org/eclipse/jgit/util/io/AutoCRLFInputStream.java

@@ -58,9 +58,12 @@ import org.eclipse.jgit.diff.RawText;
  * of binary files, canonicalization is turned off (for the complete file).
  */
 public class AutoCRLFInputStream extends InputStream {
+
+	static final int BUFFER_SIZE = 8096;
+
 	private final byte[] single = new byte[1];
 
-	private final byte[] buf = new byte[8096];
+	private final byte[] buf = new byte[BUFFER_SIZE];
 
 	private final InputStream in;