use openTestDB for the test.

Author: krasi-georgiev

db_test.go

@@ -752,16 +752,13 @@ func TestTombstoneClean(t *testing.T) {
 }
 
 func TestDB_Retention(t *testing.T) {
-	tmpdir, _ := ioutil.TempDir("", "test")
-	defer os.RemoveAll(tmpdir)
-
-	db, err := Open(tmpdir, nil, nil, nil)
-	testutil.Ok(t, err)
+	db, close := openTestDB(t, nil)
+	defer close()
 
 	lbls := labels.Labels{labels.Label{Name: "labelname", Value: "labelvalue"}}
 
 	app := db.Appender()
-	_, err = app.Add(lbls, 0, 1)
+	_, err := app.Add(lbls, 0, 1)
 	testutil.Ok(t, err)
 	testutil.Ok(t, app.Commit())