SpringBoot Return Stream<String> from OutputCaptureExtension

OutputCaptureExtension makes the stdout and stderr available as giant strings; more often than not, the test only cares about some lines and has to split the string by newline.

Consider adding methods to return Stream<String> to avoid the aforementioned boilerplate.

Comment From: wilkinsona

Thanks for the suggestion but I don't think we should do this as it would mean that CapturedOutput was taking on two responsibilities. Furthermore, with Java 11 or later the conversion is a single call to String.lines(). If you can't use Java 11 or later, a static utility method can fill the gap for you in the meantime.