Testing what's written to a Java OutputStream

Question

I am about to write junit tests for a XML parsing Java class that outputs directly to an OutputStream. For example xmlWriter.writeString(\"foo\"); would produce

Answer 1

Use a ByteArrayOutputStream and then get the data out of that using toByteArray(). This won't test how it writes to the stream (one byte at a time or as a big buffer) but usually you shouldn't care about that anyway.