diff --git a/rsc3/tests/regression-tests.rkt b/rsc3/tests/regression-tests.rkt
new file mode 100644
index 0000000..aabe3bd
--- /dev/null
+++ b/rsc3/tests/regression-tests.rkt
@@ -0,0 +1,36 @@
+#lang racket
+
+;; regression tests for rsc3/main.rkt
+
+(require rsc3
+         rackunit)
+
+
+;; name, ugen expr -> bytes (synthdef)
+;; similar to send-synth in rsc3
+(define (ugens->synthdef name ugens)
+  (encode-graphdef (synthdef name ugens)))
+
+
+;; these should not break
+
+(check-equal? (ugens->synthdef "sine" (mul (sin-osc ar 440 0) 0.1))
+              (bytes-append
+               #"SCgf\0\0\0\0\0\1\4sine\0\3C\334\0\0\0\0\0\0=\314\314\315"
+               #"\0\0\0\0\0\2\6SinOsc\2\0\2\0\1\0\0\377\377\0\0\377\377\0\1\2"
+               #"\fBinaryOpUGen\2\0\2\0\1\0\2\0\0\0\0\377\377\0\2\2"))
+
+(check-equal? (ugens->synthdef "sine0" (out 0 (mul (sin-osc ar 440 0) 0.1)))
+              (bytes-append
+               #"SCgf\0\0\0\0\0\1\5sine0\0\3\0\0\0\0C\334\0\0=\314\314\315"
+               #"\0\0\0\0\0\3\6SinOsc\2\0\2\0\1\0\0\377\377\0\1\377\377\0\0\2"
+               #"\fBinaryOpUGen\2\0\2\0\1\0\2\0\0\0\0\377\377\0\2\2\3Out\2\0\2"
+               #"\0\0\0\0\377\377\0\0\0\1\0\0"))
+
+(check-equal? (ugens->synthdef "ring" (out 0 (mul (ring4 (f-sin-osc ar 800 0)
+                                                         (f-sin-osc ar (x-line kr 200 500 5 do-nothing) 0))
+                                                  0.125)))
+              #"SCgf\0\0\0\0\0\1\4ring\0\6\0\0\0\0DH\0\0CH\0\0C\372\0\0@\240\0\0>\0\0\0\0\0\0\0\0\6\5XLine\1\0\4\0\1\0\0\377\377\0\2\377\377\0\3\377\377\0\4\377\377\0\0\1\aFSinOsc\2\0\2\0\1\0\0\0\0\0\0\377\377\0\0\2\aFSinOsc\2\0\2\0\1\0\0\377\377\0\1\377\377\0\0\2\fBinaryOpUGen\2\0\2\0\1\0!\0\2\0\0\0\1\0\0\2\fBinaryOpUGen\2\0\2\0\1\0\2\0\3\0\0\377\377\0\5\2\3Out\2\0\2\0\0\0\0\377\377\0\0\0\4\0\0")
+
+
+