diff --git a/functional-tests/logging.scm b/functional-tests/logging.scm
new file mode 100644
index 0000000..745fb1f
--- /dev/null
+++ b/functional-tests/logging.scm
@@ -0,0 +1,41 @@
+(library
+  (logging)
+
+  (export with-log-port-thunk
+          with-log-port
+          info
+          warn
+          log-error)
+
+  (import (chezscheme)
+          (fmt fmt)
+          (list-utils)
+          (utils))
+
+  (define log-port (current-error-port))
+
+  (define (with-log-port-thunk port thunk)
+    (fluid-let ((log-port port))
+      (thunk)))
+
+  (define-syntax with-log-port
+    (syntax-rules ()
+      ((_ port b1 b2 ...)
+       (with-log-port-thunk port
+         (lambda ()
+           b1 b2 ...)))))
+
+  ;; FIXME: include timestamp
+  (define (output-to-log level doc)
+    (fmt log-port
+         (dsp (symbol->string level))
+         (dsp ": ")
+         (apply cat (intersperse (dsp " ") doc))))
+
+  (define-syntax define-level
+    (syntax-rules ()
+      ((_ sym level) (define (sym . doc) (output-to-log 'level doc)))))
+
+  (define-level info info)
+  (define-level warn warn)
+  (define-level log-error error))