the env type represents a test environment. This was added as an
intermediate container that could store the saved fields of tests after
they're run, so that future tests could load them. Previously a test
could only get the attributes of the test that immediately preceded it.
This change allows tests to load attributes further back in the history.
this isn't going to work permanently, if there's a save field in one
test, then an intermediate test without that field, then a load field,
it won't be visible at the end test.