1 -*- mode: markdown; coding: utf-8-unix; -*-
3 CL-MOCK - Mocking functions.
5 Copyright (C) 2013-14 Olof-Joachim Frahm
7 Release under a Simplified BSD license.
9 Working, but unfinished.
16 This small library provides a way to replace the actual implementation
17 of either regular or generic functions with mocks. On the one hand how
18 to integrate this facility with a testing library is up to the user; the
19 tests for the library are written in [`FIVEAM`][2] though, so most
20 examples will take that into account. On the other hand writing
21 interactions for mocks usually relies on a bit of pattern matching,
22 therefore the regular `CL-MOCK` package relies on [`OPTIMA`][3] to
23 provide that facility instead of deferring to the user. Should this be
24 a concern a reduced system definition is available as `CL-MOCK-BASIC`,
25 which excludes the definition of `ANSWER` and the dependency on
28 Since it is pretty easy to just roll something like this on your own,
29 the main purpose is to develop a nice (lispy, declarative) syntax to
30 keep your tests readable and maintainable.
32 Some parts may be used independently of the testing facilities,
33 e.g. dynamic `FLET` may be of general interest.
36 # MOCKING REGULAR FUNCTIONS
38 Let's say we have a function `FOO`, then we can replace it for testing
39 by establishing a new mocking context and then specifying how the new
40 function should behave (see below in **UTILITIES** for a more primitive
41 dynamic function rebinding):
43 > (declaim (notinline foo bar))
51 > (eql 23 (foo 'bar))))
54 The `ANSWER` macro has pattern matching (see [`OPTIMA`][3]) integrated.
55 Therefore something like the following will now work as expected:
58 > (answer (foo x) (format T "Hello, ~A!" x))
62 If you don't like `ANSWER` as it is, you can still use `IF-CALLED`
63 directly. Note however that unless `UNHANDLED` is called, the function
64 always matches and the return value is directly returned again:
67 > (if-called 'foo (lambda (x)
69 > (error "Not executed!")))
70 > (if-called 'foo (lambda (x) (format T "Hello, ~A!" x)))
74 Be especially careful to handle all given arguments, otherwise the
75 function call will fail and that error is propagated upwards.
77 `IF-CALLED` also has another option to push a binding to the front of
78 the list, which (as of now) isn't available via `ANSWER` (and should be
79 treated as subject to change anyway).
81 The function `INVOCATIONS` may be used to retrieve all recorded
82 invocations of mocks (so far); the optional argument can be used to
83 filter for a particular name:
94 Currently there are no further predicates to check these values, this is
95 however an area of investigation, so presumably either a macro like
96 [`FIVEAM`][2]s `IS`, or regular predicates could appear in this place.
101 `DFLET` dynamically rebinds functions similar to `FLET`:
104 > (defun bar () (foo))
107 > (dflet ((foo () 23))
110 > (OR) => 42, if FOO was inlined
112 The caveat is that this might not work on certain optimisation settings,
113 including inlining. That trade-off seems acceptable; it would be nice
114 if a warning could be issued depending on the current optimisation
115 settings, however that is particularly implementation dependent, so lack
116 of a warning won't indicate a working environment.
118 The underlying function `PROGF` may be used as well similarly to the
121 > (progf '(foo) (list (lambda () 23))
124 > (OR) => 42, if FOO was inlined
126 [1]: http://common-lisp.net/project/closer/closer-mop.html
127 [2]: http://common-lisp.net/project/fiveam/
128 [3]: https://github.com/m2ym/optima