Repl tests

[porcuquine]

I think this is the minimum viable REPL/CLI test machinery we need. It does the following:

• Adds support for !(:do-something …) toplevel 'script' forms.
• Evaluates multiple forms when 'running'.
• Add support for running from CLI when filenames are provided as arguments.
• Adds !(:assert …) and !(:assert-eq …) script forms, for minimal testing.
• Adds `!(:load …) script form for self-contained test files.
• Rename 'repl/xtolurk/x`.
• lurk returns non-zero exit code if there is an assertion failure.
• lurk returns exit code zero if there are no errors in reading, evaluation, and no assertions fail.
• Extant tests are rewritten to use :load, :assert-eq, :assert.
• New example-suite tests are added, which directly invoke the CLI on designated test examples.

TODO:

• :impl tests (lang.lisp) are disabled because of a (previously-known see #10) bug. This should be fixed, then the tests enabled.
• The lurk-rs REPL needs to be extended to support these tests, and they should be added to the test suite there.
• There should be a test-specifying mechanism (which could initially be as simple as checking for the substring 'test' in filenames) to ensure new tests are included in both places. (A designated test directory is another option.)
• .lurk files should allow comments.
• Not directly related, but important: set up CI on the repo.

[porcuquine]

I would prefer if we chose the option not to duplicate the tests for lurk-rs.

Can you clarify what you mean? I think I've lost track of the context.

My current plan is to enable lurk-rs to process the .lurk test files and succeed/fail appropriately. Are you saying you agree with this plan, or something else?

[namin]

Yes, that sounds good. I am referring to this comment:

The lurk-rs REPL needs to be extended to support these tests, and they should be added to the test suite there.

I just want to make sure we don't duplicate the test suite. Maybe have the convention that both of these projects are in sibling directories?

[porcuquine]

I understand what you mean now, thanks.

I wonder if the cleanest thing would be to move the tests to their own repo and make it a submodule of both lurk and lurk-rs.

I definitely agree that the test source files should not be duplicated.

[porcuquine]

Here is a PR to added support for this in lurk-rs: https://github.com/lurk-lang/lurk-rs/pull/10.