diff --git a/tests/various/.gitignore b/tests/various/.gitignore
index da78b6ec5..83e634820 100644
--- a/tests/various/.gitignore
+++ b/tests/various/.gitignore
@@ -7,3 +7,4 @@
 /plugin.so.dSYM
 /temp
 /smtlib2_module.smt2
+/smtlib2_module-filtered.smt2
diff --git a/tests/various/smtlib2_module.sh b/tests/various/smtlib2_module.sh
index a280da487..9b2f24f9f 100755
--- a/tests/various/smtlib2_module.sh
+++ b/tests/various/smtlib2_module.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
 set -ex
 ../../yosys -q -p 'read_verilog -formal smtlib2_module.v; prep; write_smt2 smtlib2_module.smt2'
-sed -i 's/; SMT-LIBv2 description generated by Yosys .*/; SMT-LIBv2 description generated by Yosys $VERSION/' smtlib2_module.smt2
-diff -au smtlib2_module-expected.smt2 smtlib2_module.smt2
+sed 's/; SMT-LIBv2 description generated by Yosys .*/; SMT-LIBv2 description generated by Yosys $VERSION/' smtlib2_module.smt2 > smtlib2_module-filtered.smt2
+diff -au smtlib2_module-expected.smt2 smtlib2_module-filtered.smt2