Added rotating-triangle test.

collects/picturing-programs/tests/rotating-triangle.rkt

@@ -0,0 +1,24 @@
+;; The first three lines of this file were inserted by DrRacket. They record metadata
+;; about the language level of this file in a form that our tools can easily process.
+#reader(lib "htdp-beginner-reader.ss" "lang")((modname rotating-triangle) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ())))
+(require picturing-programs)
+
+(define R 60)
+(define SIDE (* R (sqrt 3)))
+(define TRI (triangle SIDE "solid" "blue"))
+(define CIRC (circle R "solid" "white"))
+(define tricirc (overlay/xy TRI
+                            (- (/ SIDE 2) R) 0
+                            CIRC))
+(define badtricirc
+  (overlay/align "middle" "middle"
+                 TRI
+                 CIRC))
+
+(define (rotate-1 pic)
+  (rotate 1 pic))
+
+(big-bang badtricirc
+          (on-tick rotate-1 .05)
+          (check-with image?)
+          (on-draw show-it))