diff --git a/tests/backtraces.scm b/tests/backtraces.scm
index c5f8e0e..590ab3e 100644
--- a/tests/backtraces.scm
+++ b/tests/backtraces.scm
@@ -5,9 +5,8 @@
              (ice-9 match))
 
 (define (run-backtrace-script file)
-  (let* ((pipe (open-pipe* OPEN_READ
-                            "/bin/sh" "-c"
-                            (string-append "./test-env guile " file " 2>&1")))
+  (let* ((pipe (open-pipe (string-append "./test-env guile " file " 2>&1")
+                          OPEN_READ))
          (output (read-string pipe)))
     (close-pipe pipe)
     output))