public void WriteOverMiddleBoundryOfBothStreamsWithSeekDisabled() { // Arrange byte[] result = new byte[1046]; byte[] buffer1 = Encoding.ASCII.GetBytes("123"); byte[] buffer2 = Encoding.ASCII.GetBytes("456"); byte[] bufferToWrite = Encoding.ASCII.GetBytes("abcdef"); MemoryStream stream1 = new MemoryStream(buffer1); MemoryStream stream2 = new MemoryStream(buffer2); ConcatStream streamToTest = new ConcatStream(stream1, stream2); // Act streamToTest.Write(bufferToWrite, 0, bufferToWrite.Length); //Assert string actual = streamToTest.ToString(); Assert.IsFalse(streamToTest.CanSeek); for (int i = 0; i < bufferToWrite.Length; i++) { Assert.AreEqual(actual[i], bufferToWrite[i]); } }