Add "conjoin" from chicken scheme

test.scm

@@ -63,6 +63,13 @@
     (define value (upply -3 5 = abs 1-))
     (assert-equal #t value)))
 
+(define-test-suite "conjoin"
+  (define-test "test"
+    (assert-equal #t ((conjoin negative? odd? rational?) -3))
+    (assert-equal #f ((conjoin negative? odd? rational?) -4)))
+  (define-test "vacuous"
+    (assert-equal #t ((conjoin) '(some donkus)))))
+
 (define-test-suite "generator"
   (define-test "test"
     (define number-generator