public void TestWrite() { using (var stream = new SmtpStream(new DummyNetworkStream(), new NullProtocolLogger())) { var memory = (MemoryStream)stream.Stream; var buffer = new byte[8192]; var buf1k = new byte[1024]; var buf4k = new byte[4096]; var buf9k = new byte[9216]; byte[] mem; using (var rng = new RNGCryptoServiceProvider()) { rng.GetBytes(buf1k); rng.GetBytes(buf4k); rng.GetBytes(buf9k); } Assert.Throws <ArgumentNullException> (() => stream.Write(null, 0, buffer.Length)); Assert.Throws <ArgumentOutOfRangeException> (() => stream.Write(buffer, -1, buffer.Length)); Assert.Throws <ArgumentOutOfRangeException> (() => stream.Write(buffer, 0, -1)); // Test #1: write less than 4K to make sure that SmtpStream buffers it stream.Write(buf1k, 0, buf1k.Length); Assert.AreEqual(0, memory.Length, "#1"); // Test #2: make sure that flushing the SmtpStream flushes the entire buffer out to the network stream.Flush(); Assert.AreEqual(buf1k.Length, memory.Length, "#2"); mem = memory.GetBuffer(); for (int i = 0; i < buf1k.Length; i++) { Assert.AreEqual(buf1k[i], mem[i], "#2 byte[{0}]", i); } memory.SetLength(0); // Test #3: write exactly 4K to make sure it passes through w/o the need to flush stream.Write(buf4k, 0, buf4k.Length); Assert.AreEqual(buf4k.Length, memory.Length, "#3"); mem = memory.GetBuffer(); for (int i = 0; i < buf4k.Length; i++) { Assert.AreEqual(buf4k[i], mem[i], "#3 byte[{0}]", i); } memory.SetLength(0); // Test #4: write 1k and then write 4k, make sure that only 4k passes thru (last 1k gets buffered) stream.Write(buf1k, 0, buf1k.Length); stream.Write(buf4k, 0, buf4k.Length); Assert.AreEqual(4096, memory.Length, "#4"); stream.Flush(); Assert.AreEqual(buf1k.Length + buf4k.Length, memory.Length, "#4"); Array.Copy(buf1k, 0, buffer, 0, buf1k.Length); Array.Copy(buf4k, 0, buffer, buf1k.Length, buf4k.Length); mem = memory.GetBuffer(); for (int i = 0; i < buf1k.Length + buf4k.Length; i++) { Assert.AreEqual(buffer[i], mem[i], "#4 byte[{0}]", i); } memory.SetLength(0); // Test #5: write 9k and make sure only the first 8k goes thru (last 1k gets buffered) stream.Write(buf9k, 0, buf9k.Length); Assert.AreEqual(8192, memory.Length, "#5"); stream.Flush(); Assert.AreEqual(buf9k.Length, memory.Length, "#5"); mem = memory.GetBuffer(); for (int i = 0; i < buf9k.Length; i++) { Assert.AreEqual(buf9k[i], mem[i], "#5 byte[{0}]", i); } memory.SetLength(0); } }