Function: `mh-test-completion`

mh-test-completion is a for test-completion, defined in minibuf.c.

Signature

(mh-test-completion STRING COLLECTION &optional PREDICATE)

Return non-nil if STRING is a valid completion.

For instance, if COLLECTION is a list of strings, STRING is a valid completion if it appears in the list and PREDICATE is satisfied.

Takes the same arguments as all-completions and try-completion.

If COLLECTION is a function, it is called with three arguments: the values STRING, PREDICATE and lambda.