add test for the prev bugfix

t/issue/pic_call.scm

@@ -0,0 +1,24 @@
+(import (scheme base)
+        (scheme read)
+        (scheme file)
+        (scheme lazy)
+        (scheme write)
+        (srfi 1)
+        (picrin base)
+        (picrin test))
+
+(test-begin)
+
+(define trace '())
+
+(define task-queue (make-parameter '() (lambda (x) (set! trace (cons x trace)) x)))
+
+(define expand
+  (lambda ()
+    (task-queue)))
+
+(define result (expand))
+(test '() result)
+(test '(()) trace)
+
+(test-end)