branch: elpa/buttercup
commit 8aa87c89eb93474ef784664d5404fec5c9c31c71
Author: Jorgen Schaefer <cont...@jorgenschaefer.de>
Commit: Jorgen Schaefer <cont...@jorgenschaefer.de>
Spy :and-call-through
---
README.md | 26 ++++++++++++++++++++++++++
buttercup-test.el | 14 ++++++++++++++
buttercup.el | 15 +++++++++++----
3 files changed, 51 insertions(+), 4 deletions(-)
diff --git a/README.md b/README.md
index 20062db..34a56a2 100644
--- a/README.md
+++ b/README.md
@@ -344,6 +344,32 @@ the argument list matches any of the recorded calls to the
spy.
(expect bar :to-be nil))))
```
+### Spies: `:and-call-through`
+
+The keyword argument `:and-call-through` to `spy-on` will make the spy
+call the original function instead of returning `nil`.
+
+```Lisp
+(describe "A spy, when configured to call through"
+ (let (bar set-bar get-bar fetched-bar)
+ (before-each
+ (fset 'set-bar (lambda (val)
+ (setq bar val)))
+ (fset 'get-bar (lambda ()
+ bar))
+
+ (spy-on 'get-bar :and-call-through)
+
+ (set-bar 123)
+ (setq fetched-bar (get-bar)))
+
+ (it "tracks that the spy was called"
+ (expect 'get-bar :to-have-been-called))
+
+ (it "should not affect other functions"
+ (expect bar :to-equal 123))))
+```
+
## Test Runners
Evaluating `describe` forms just stores the suites. You need to use a
diff --git a/buttercup-test.el b/buttercup-test.el
index cb071c4..bb30b9c 100644
--- a/buttercup-test.el
+++ b/buttercup-test.el
@@ -377,3 +377,17 @@
:to-have-been-called-with '(test-function 1 2 3))
:to-be
t)))
+
+(describe "The :and-call-through keyword functionality"
+ (before-each
+ (spy-on 'test-function :and-call-through))
+
+ (it "tracks calls to the function"
+ (test-function 42 23)
+
+ (expect 'test-function :to-have-been-called))
+
+ (it "passes the arguments to the original function"
+ (expect (test-function 2 3)
+ :to-equal
+ 5)))
diff --git a/buttercup.el b/buttercup.el
index 87c6d7f..916dbc8 100644
--- a/buttercup.el
+++ b/buttercup.el
@@ -368,11 +368,18 @@ A disabled spec is not run."
(defvar buttercup--spy-calls (make-hash-table :test 'eq
:weakness 'key))
-(defun spy-on (symbol)
- (letrec ((old-value (symbol-function symbol))
- (new-value (lambda (&rest args)
+(defun spy-on (symbol &rest keyword-args)
+ (let ((old-value (symbol-function symbol))
+ (new-value nil))
+ (cond
+ ((equal keyword-args '(:and-call-through))
+ (setq new-value (lambda (&rest args)
(buttercup--spy-add-call new-value args)
- nil)))
+ (apply old-value args))))
+ ((equal keyword-args nil)
+ (setq new-value (lambda (&rest args)
+ (buttercup--spy-add-call new-value args)
+ nil))))
(fset symbol new-value)
(buttercup--add-cleanup (lambda () (fset symbol old-value)))))
