diff --git a/test/T090-search-output.sh b/test/T090-search-output.sh
index 86544ac9..a8ab9205 100755
--- a/test/T090-search-output.sh
+++ b/test/T090-search-output.sh
@@ -181,7 +181,7 @@ EOF
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "--output=files"
-notmuch search --output=files '*' | sed -e "s,$MAIL_DIR,MAIL_DIR," >OUTPUT
+notmuch search --output=files '*' | notmuch_search_files_sanitize >OUTPUT
 cat <<EOF >EXPECTED
 MAIL_DIR/cur/52:2,
 MAIL_DIR/cur/53:2,
@@ -240,7 +240,7 @@ EOF
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "--output=files --duplicate=1"
-notmuch search --output=files --duplicate=1 '*' | sed -e "s,$MAIL_DIR,MAIL_DIR," >OUTPUT
+notmuch search --output=files --duplicate=1 '*' | notmuch_search_files_sanitize >OUTPUT
 cat <<EOF >EXPECTED
 MAIL_DIR/cur/52:2,
 MAIL_DIR/cur/53:2,
@@ -298,7 +298,7 @@ EOF
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "--output=files --format=json"
-notmuch search --format=json --output=files '*' | sed -e "s,$MAIL_DIR,MAIL_DIR," >OUTPUT
+notmuch search --format=json --output=files '*' | notmuch_search_files_sanitize >OUTPUT
 cat <<EOF >EXPECTED
 ["MAIL_DIR/cur/52:2,",
 "MAIL_DIR/cur/53:2,",
@@ -357,7 +357,7 @@ EOF
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "--output=files --format=json --duplicate=2"
-notmuch search --format=json --output=files --duplicate=2 '*' | sed -e "s,$MAIL_DIR,MAIL_DIR," >OUTPUT
+notmuch search --format=json --output=files --duplicate=2 '*' | notmuch_search_files_sanitize >OUTPUT
 cat <<EOF >EXPECTED
 ["MAIL_DIR/cur/51:2,"]
 EOF
diff --git a/test/T370-search-folder-coherence.sh b/test/T370-search-folder-coherence.sh
index 3f6ec763..5e72a6cc 100755
--- a/test/T370-search-folder-coherence.sh
+++ b/test/T370-search-folder-coherence.sh
@@ -27,7 +27,7 @@ cat <<EOF >EXPECTED
 MAIL_DIR/msg-001
 MAIL_DIR/spam/msg-001
 EOF
-notmuch search --output=files id:$id_x | sed -e "s,$MAIL_DIR,MAIL_DIR," >OUTPUT
+notmuch search --output=files id:$id_x | notmuch_search_files_sanitize >OUTPUT
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "Test matches folder:spam"
diff --git a/test/test-lib.sh b/test/test-lib.sh
index 9824bb67..8697d6a7 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -667,6 +667,11 @@ notmuch_search_sanitize ()
     perl -pe 's/("?thread"?: ?)("?)................("?)/\1\2XXX\3/'
 }
 
+notmuch_search_files_sanitize()
+{
+    sed -e "s,$MAIL_DIR,MAIL_DIR,"
+}
+
 NOTMUCH_SHOW_FILENAME_SQUELCH='s,filename:.*/mail,filename:/XXX/mail,'
 notmuch_show_sanitize ()
 {