From 1.1 to 1.2:
- Official support for Guile dropped.  Most everything should still
  work.  I don't know how hard the rest is to port.
- There is now a check macro that is largely meant to replace the
  assert-foo procedures.
  - Also define-each-check, which is a combination of define-each-test
    and check
- The notion of "matching" is now extensible via the generic (in the
  sense of SOS) procedure generic-match.  Default methods are provided
  for general objects, vectors, lists, and floating-point numbers, as
  well as interpreting string patterns as regular expressions.
  (MIT Scheme only)
- There is now an interaction macro for writing tests that look
  like REPL sessions.  It does with a produces procedure that refers
  to the value of the last evaluated form, and works within calls to
  the interaction macro and at the REPL (REPL is MIT Scheme only).
- Assertions assert-< assert-> assert-<= assert->= added
- It is now an intentional, supported feature that you can use
  a delayed expression in the assertion failure message position
  to do arbitrary computation if the assertion fails.  The return
  value of said computation will be printed as an additional message
  in the failure report; and the suite will not crash even if that
  value fails to be a string.
- There is now a clear-registered-tests! procedure for interactive use.

From 1.0 to 1.1:

- You can now use promises (made by delay) as assertion failure
  messages.  If the message is a promise, the framework will only
  force it if the assertion fails.
- Added assert-no-match to complement assert-matches.
- Tests now understand docstrings, meaning they print them if the test
  fails.  Single-form tests use the test form itself as the docstring.
- Added define-each-test to make single-form tests out of each of its
  argument expressions.  This is a convenience over writing
  (define-test (assert-foo ... )) over and over.