[nongnu] elpa/buttercup 7cdb219 028/340: Spies: :and-call-fake

[ELPA Syncer]

branch: elpa/buttercup
commit 7cdb2191767f051c990b8f6ea76e94f6377d0ad0
Author: Jorgen Schaefer <contact@jorgenschaefer.de>
Commit: Jorgen Schaefer <contact@jorgenschaefer.de>

    Spies: :and-call-fake
---
 README.md         | 30 ++++++++++++++++++++++++++++++
 buttercup-test.el | 14 ++++++++++++++
 buttercup.el      |  4 ++++
 3 files changed, 48 insertions(+)

diff --git a/README.md b/README.md
index 70c6bbd..8eaad06 100644
--- a/README.md
+++ b/README.md
@@ -402,6 +402,36 @@ spied-on function should return.
       (expect fetched-bar :to-equal 745))))
 ```
 
+### Spies: `:and-call-fake`
+
+The keyword argument `:and-call-fake` delegates calls to a supplied
+function.
+
+```Lisp
+(describe "A spy, when configured with an alternate implementation"
+  (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-fake (lambda () 1001))
+
+      (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))
+
+    (it "when called returns the requested value"
+      (expect fetched-bar :to-equal 1001))))
+```
+
+
 ## 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 5fe85b8..3fc2119 100644
--- a/buttercup-test.el
+++ b/buttercup-test.el
@@ -405,3 +405,17 @@
     (expect (test-function 2 3)
             :to-equal
             23)))
+
+(describe "The :and-call-fake keyword functionality"
+  (before-each
+    (spy-on 'test-function :and-call-fake (lambda (a b) 1001)))
+
+  (it "tracks calls to the function"
+    (test-function 42 23)
+
+    (expect 'test-function :to-have-been-called))
+
+  (it "returns the specified value"
+    (expect (test-function 2 3)
+            :to-equal
+            1001)))
diff --git a/buttercup.el b/buttercup.el
index 72f02c7..83e3c6e 100644
--- a/buttercup.el
+++ b/buttercup.el
@@ -380,6 +380,10 @@ A disabled spec is not run."
       (setq new-value (lambda (&rest args)
                         (buttercup--spy-add-call new-value args)
                         arg)))
+     ((eq keyword :and-call-fake)
+      (setq new-value (lambda (&rest args)
+                        (buttercup--spy-add-call new-value args)
+                        (apply arg args))))
      ((not keyword)
       (setq new-value (lambda (&rest args)
                         (buttercup--spy-add-call new-value args)