From 1b6d6ca4dba3118d969e497b2086481c9d1ade59 Mon Sep 17 00:00:00 2001 From: Colin Okay Date: Wed, 7 Sep 2022 10:26:14 -0500 Subject: Add: README.org --- README.org | 175 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 175 insertions(+) create mode 100644 README.org diff --git a/README.org b/README.org new file mode 100644 index 0000000..f224b46 --- /dev/null +++ b/README.org @@ -0,0 +1,175 @@ +A [[https://en.wiktionary.org/wiki/testiere][testiere]] is armor for the head of a horse and ~testiere~ is armor +for the head of your ~defun~ forms. + +* Testiere + +With ~testiere~ you can program in an interactive TDD-like +fashion. Tests are included at the top of a ~defun/t~ form. When you +recompile your functions interactively, the tests are run. If any +fail, you are dropped into a debugger where you can decide to revert +the definition to the last known working version, or you can choose to +unbind it altogether. + +The system supports mocking and stubbing in your tests, so that you +can, e.g. test the system in different dynamic contexts or by mocking +network request functions. + +Here is an example: + +#+begin_src lisp + +(defun/t sum-3 (x y &key (z 10)) + "Sums three numbers, Z has a default value of 10" + :tests + (:program some-test-function) + (= (1 2) 13) ; (sum-3 1 2) == 13 + (= (1 2 :z 3) 6) ; (sum-3 1 2 :z 3) == 6 + (:output (0 0) ; tests that (sum-3 0 0) passes the predicate + (lambda (result) (= 10 result))) + (:fails ; ensures that (sum-3 "strings" "ain't" :z "numbers") fails + ("strings" "ain't" :z "numbers")) + :end + (+ x y z)) + +#+end_src + +In the above, a function ~sum-3~ is defined with five embedded +tests. The test specification syntax is detailed below. If any of the +tests fail, the function will not be redefined and you will drop into +the debugger, which asks you how you'd like to proceed. + +The approach to TDD-like development taking by ~testiere~ may not be +appropriate to all circumstances, but it is good for interactive +application development of interactive applications (😉) whose "main +loop" involves a good sized collection of unit-testable functions. + +** Test Specification + +There are a few kinds of tests available. + +*** For the Impatient, Just Use =:program= Tests + +Most users will probably benefit from the ~:program~ style test. Here +is a quick example: + +#+begin_src lisp + +(defun test-fibble () + (assert (= 13 (fibble 1 2)))) + +(defun/t fibble (x y &key (z 10)) + "Adds three numbers, one of which defaults to 10." + :tests + (:program test-fibble) + :end + (+ x y z)) + +#+end_src + +In the above test, we insist that the ~test-fibble~ function not +signal an error condition in order for ~fibble~ to be successfully +(re)compiled. + +*** Basic Test Specifications + +A test suite is a list of forms that appear between ~:tests~ and +~:end~ in the body of a ~defun/t~ form. The test suite must appear +after any optional docstring and before the function body actually +begins. + +A catalog of test form specifications follows. + +**** Comparator Test Specifications + +: (comparator (&rest args...) value) + +The ~comparator~ should be the name of a binary predicate (like ~<~ or +~eql~). These tests proceed by calling ~(comparator (apply my-fun args) value)~ +If the comparison fails, an error condition is signaled. + +Amending the above example, we include a comparator test: + + +#+begin_src lisp +(defun/t fibble (x y &key (z 10)) + "Adds three numbers, one of which defaults to 10." + :tests + (:program test-fibble) + (= (0 0 :z 39) 30) ; (assert (= (fibble 0 0 :z 30) 30)) + :end + (+ x y z)) + +#+end_src + +**** Other Test Specifications + +Every other form appearing in a test suite is a list that starts with +a keyword. + +- ~(:program FUNCTION-NAME ARGS...)~ runs a function named + FUNCTION-NAME with arguments ARGS. This function is meant to act as + a test suite for the function being defined with defun/t. It may + call that function and ASSERT things about it. +- ~(:outputp (..ARGS...) PREDICATE)~ asserts that the output passes + the one-argument predicate. +- ~(:afterp (...ARGS...) THUNK)~ asserts that the thunk should return + non-nil after the function has run. Good for testing values of + dynamic variables that the function might interact with. +- ~(:fails (...ARGS...))~ asserts that the function will produce an + error with the given arguments. +- ~(:signals (...ARGS...) CONDITION)~ where ~CONDITION~ is the name of + a condition. Asserts that the function will signal a condition of + the supplied type when called with the provided arguments. + + +*** Mocking and Stubbing + +The following test forms allow for the running of tests inside a +context in which certain functions or global values are bound: + +Binding variables looks like + +: (:let LET-BINDINGS TESTS) + +and are useful for binding dynamic variables for use during a set of +tests. + +For example + +#+begin_src lisp + + (defvar *count*) + + (defun/t increment-count () + "Increments the *count* variable." + :tests + (:let ((*count* 4)) + (:afterp () (lambda () (= *count* 5))) ; 5 after the first call + (= () 6) ; 6 after the second + (:outputp () (lambda (x) (= x 7)))) ; and 7 after the third + :end + (incf *count*)) +#+end_src + +The ~:with-stubs~ form is similar, except that it binds temporary +values to functions that might be called by the form in +questions. Useful for mocking. + +#+begin_src lisp + + + (defun just-a-function () + (print "Just a function.")) + + (defun/t call-just-a-function () + "Calls JUST-A-FUNCTION." + :tests + (:with-stubs ((just-a-function () (print "TEMP JUST-A-FUNCTION."))) + (equal () "TEMP JUST-A-FUNCTION.")) + :end + (just-a-function)) + +#+end_src + +In the above, the temporary redefinition of ~JUST-A-FUNCTION~ is used. + -- cgit v1.2.3