--- a/tests/test_read_write.sh
+++ b/tests/test_read_write.sh
@@ -25,7 +25,7 @@ EXIT_FAILURE=1;
 EXIT_IGNORE=77;
 
 INPUT="input";
-TMP="tmp";
+TMP=$(mktemp -ut);
 
 LS="ls";
 TR="tr";
--- a/tests/test_read_write_delta.sh
+++ b/tests/test_read_write_delta.sh
@@ -25,7 +25,7 @@ EXIT_FAILURE=1;
 EXIT_IGNORE=77;
 
 INPUT="input";
-TMP="tmp";
+TMP=$(mktemp -ut);
 
 AWK="awk";
 CUT="cut";
--- a/tests/test_write.sh
+++ b/tests/test_write.sh
@@ -24,7 +24,7 @@ EXIT_SUCCESS=0;
 EXIT_FAILURE=1;
 EXIT_IGNORE=77;
 
-TMP="tmp";
+TMP=$(mktemp -ut);
 
 CUT="cut";