Data update

Task/Test-a-function/Insitux/test-a-function.insitux

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+(var palindrome? (comp (filter letter?) lower-case (= (reverse %))))
+
+;Arrange
+(var calls [])
+(function record f
+  (fn (var! calls (append f))
+      (... (unmocked f) args)))
+
+(mock comp       (record comp)
+      filter     (record filter)
+      letter?    (record letter?)
+      lower-case (record lower-case)
+      =          (record =)
+      reverse    (record reverse))
+
+(var sentence "In girum imus nocte et consumimur igni.")
+
+;Act
+(var result (palindrome? sentence))
+
+(unmock comp filter letter? lower-case = reverse)
+
+;Assert
+(assert result)
+
+(var occurred (freqs calls))
+(assert (= (len sentence) (occurred letter?)))                  ;letter? is called (len sentence) times
+(assert (... = 1 (map occurred [filter lower-case reverse =]))) ;other functions are called only once