[racket-dev] The Clark XML tests & licensing

Summary: we are currently violating the license of James Clark's XML
test suite, and should fix this.

Currently, the `tests/xml' directory [1] contains a comprehensive
collection tests for XML parsing from James Clark [2].  The
readme.html file [3] in that directory states the license of that test
suite:

  Copyright (C) 1998 James Clark. All rights reserved. Permission is
  granted to copy and modify this collection in any way for internal use
  within a company or organization. Permission is granted to
  redistribute the file <code>xmltest.zip</code> containing this
  collection to third parties provided that no modifications of any kind
  are made to this file. Note that permission to distribute the
  collection in any other form is not granted.

See in particular the last sentence.  We're clearly violating this
license, since we distribute the unzipped collection.  We need to fix
this.

Fortunately, this should be easy to fix.  We need to do the following:

1. Remove the 'clark-tests' directory.
2. Add the 'xmltest.zip' file.
3. Unzip the file on-demand when running the tests.

Currently, we don't have a Racket interface to unzip files.  We could
use the command-line 'unzip' tool, or write such an interface., or
perhaps someone's already written one.

[1] https://github.com/plt/racket/tree/master/collects/tests/xml/clark-tests
[2] ftp://ftp.jclark.com/pub/xml/xmltest.zip
[3] https://github.com/plt/racket/blob/master/collects/tests/xml/clark-tests/readme.html
-- 
sam th
samth at ccs.neu.edu