diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/SideBandInputStreamTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/SideBandInputStreamTest.java
new file mode 100644
index 000000000..497f584b5
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/SideBandInputStreamTest.java
@@ -0,0 +1,212 @@
+/*
+ * Copyright (C) 2022 Thomas Wolf <thomas.wolf@paranor.ch> and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * https://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+package org.eclipse.jgit.transport;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
+import java.nio.charset.StandardCharsets;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class SideBandInputStreamTest {
+
+	private StringWriter messages;
+
+	private SideBandInputStream sideband;
+
+	@Before
+	public void setup() {
+		messages = new StringWriter();
+	}
+
+	@Test
+	public void progressSingleCR() throws IOException {
+		init(packet("message\r"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message\r", messages.toString());
+	}
+
+	@Test
+	public void progressSingleLF() throws IOException {
+		init(packet("message\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message\n", messages.toString());
+	}
+
+	@Test
+	public void progressSingleCRLF() throws IOException {
+		init(packet("message\r\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressMultiCR() throws IOException {
+		init(packet("message   0%\rmessage 100%\r"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\rmessage 100%\r", messages.toString());
+	}
+
+	@Test
+	public void progressMultiLF() throws IOException {
+		init(packet("message   0%\nmessage 100%\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\nmessage 100%\n", messages.toString());
+	}
+
+	@Test
+	public void progressMultiCRLF() throws IOException {
+		init(packet("message   0%\r\nmessage 100%\r\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\r\nmessage 100%\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartial() throws IOException {
+		init(packet("message"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("", messages.toString());
+	}
+
+	@Test
+	public void progressPartialTwoCR() throws IOException {
+		init(packet("message") + packet("message\r"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessage\r", messages.toString());
+	}
+
+	@Test
+	public void progressPartialTwoLF() throws IOException {
+		init(packet("message") + packet("message\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessage\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialTwoCRLF() throws IOException {
+		init(packet("message") + packet("message\r\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessage\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialThreeCR() throws IOException {
+		init(packet("message") + packet("message") + packet("message\r"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessagemessage\r", messages.toString());
+	}
+
+	@Test
+	public void progressPartialThreeLF() throws IOException {
+		init(packet("message") + packet("message") + packet("message\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessagemessage\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialThreeCRLF() throws IOException {
+		init(packet("message") + packet("message") + packet("message\r\n"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("messagemessagemessage\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialCR() throws IOException {
+		init(packet("message   0%\rmessage 100%"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\r", messages.toString());
+	}
+
+	@Test
+	public void progressPartialLF() throws IOException {
+		init(packet("message   0%\nmessage 100%"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialCRLF() throws IOException {
+		init(packet("message   0%\r\nmessage 100%"));
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialSplitCR() throws IOException {
+		init(packet("message") + "0006\001a" + packet("   0%\rmessa")
+				+ packet("ge 100%"));
+		assertEquals('a', sideband.read());
+		assertEquals("", messages.toString());
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\r", messages.toString());
+	}
+
+	@Test
+	public void progressPartialSplitLF() throws IOException {
+		init(packet("message") + "0006\001a" + packet("   0%\nmessa")
+				+ packet("ge 100%"));
+		assertEquals('a', sideband.read());
+		assertEquals("", messages.toString());
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\n", messages.toString());
+	}
+
+	@Test
+	public void progressPartialSplitCRLF() throws IOException {
+		init(packet("message") + "0006\001a" + packet("   0%\r\nmessa")
+				+ packet("ge 100%"));
+		assertEquals('a', sideband.read());
+		assertEquals("", messages.toString());
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\r\n", messages.toString());
+	}
+
+	@Test
+	public void progressInterleaved() throws IOException {
+		init(packet("message   0%\r") + "0006\001a" + packet("message  10%")
+				+ "0006\001b" + packet("\rmessage 100%\n"));
+		assertEquals('a', sideband.read());
+		assertEquals("message   0%\r", messages.toString());
+		assertEquals('b', sideband.read());
+		assertEquals("message   0%\r", messages.toString());
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\rmessage  10%\rmessage 100%\n",
+				messages.toString());
+	}
+
+	@Test
+	public void progressInterleavedPartial() throws IOException {
+		init(packet("message   0%\r") + "0006\001a" + packet("message  10%")
+				+ "0006\001b" + packet("\rmessage 100%"));
+		assertEquals('a', sideband.read());
+		assertEquals("message   0%\r", messages.toString());
+		assertEquals('b', sideband.read());
+		assertEquals("message   0%\r", messages.toString());
+		assertTrue(sideband.read() < 0);
+		assertEquals("message   0%\rmessage  10%\r", messages.toString());
+	}
+
+	private String packet(String data) {
+		return String.format("%04x\002%s", Integer.valueOf(data.length() + 5),
+				data);
+	}
+
+	private void init(String packets) {
+		InputStream rawIn = new ByteArrayInputStream(
+				(packets + "0000").getBytes(StandardCharsets.UTF_8));
+		sideband = new SideBandInputStream(rawIn, null, messages, null);
+	}
+}