Store.tpf public for tests

Author: joepio

lib/src/store.rs

@@ -57,7 +57,7 @@ impl Store {
     /// ```
     // Very costly, slow implementation.
     // Does not assume any indexing.
-    fn tpf(
+    pub fn tpf(
         &self,
         q_subject: Option<&str>,
         q_property: Option<&str>,