Cache only stores references.

src/morethantext/cache.rs

@@ -132,10 +132,10 @@ impl Cache {
             }
         };
         for name in data.list() {
-            match store.add(name) {
+            let id = self.ids.next().unwrap();
+            match store.add_by_id(name, &id) {
                 Ok(_) => {
-                    self.data
-                        .insert(self.ids.next().unwrap(), FromCache::DB(Database::new()));
+                    self.data.insert(id, FromCache::DB(Database::new()));
                 }
                 Err(err) => return FromCache::Error(err),
             }
@@ -228,7 +228,21 @@ mod engine {
                 db_out, cache.data
             ),
         }
-        // Add test that only ids are in the cache.
+        let store_out = cache.get(ENTRY);
+        match store_out {
+            FromCache::Str(updated_store) => match updated_store.get(name) {
+                Some(output) => {
+                    assert_eq!(output.id, Some(id.to_string()));
+                    assert!(output.data.is_none(), "Should have removed the database.");
+                }
+                None => assert!(true, "Store should have stored the database."),
+            },
+            _ => assert!(
+                false,
+                "{:?} is not FromCache::Str -- cache is {:?}",
+                db_out, cache.data
+            ),
+        }
     }
 }
 

src/morethantext/store.rs

@@ -27,6 +27,21 @@ impl Store {
         }
     }
 
+    pub fn add_by_id<S, D>(&mut self, name: S, id: D) -> Result<(), MTTError>
+    where
+        S: Into<String>,
+        D: Into<String>,
+    {
+        let db_name = name.into();
+        match self.get(&db_name) {
+            Some(_) => Err(MTTError::from_code(ErrorCode::DuplicateDatabase(db_name))),
+            None => {
+                self.data.insert(db_name, Data::from_id(id.into()));
+                Ok(())
+            }
+        }
+    }
+
     pub fn get(&self, name: &str) -> Option<&Data<Database>> {
         self.data.get(name)
     }
@@ -87,6 +102,53 @@ mod storage {
         }
     }
 
+    #[test]
+    fn add_using_cache_id() {
+        let mut store = Store::new();
+        let name = "fred";
+        let id = "12345";
+        store.add_by_id(name, id).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn add_by_cache_id_name_string() {
+        let mut store = Store::new();
+        let name = "barney";
+        let id = "67890";
+        store.add_by_id(name.to_string(), id).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
+    #[test]
+    fn no_duplicate_databases_for_add_by_id() {
+        let mut store = Store::new();
+        let name = "betty";
+        store.add_by_id(name, "fghij").unwrap();
+        match store.add_by_id(name, "klmno") {
+            Ok(_) => assert!(false, "Duplicates should error."),
+            Err(err) => match err.code {
+                ErrorCode::DuplicateDatabase(db_name) => assert_eq!(db_name, name),
+                _ => assert!(false, "{:?} is not DuplicateDatabase", err),
+            },
+        }
+    }
+
+    #[test]
+    fn add_by_cache_id_string() {
+        let mut store = Store::new();
+        let name = "wilma";
+        let id = "abcdef";
+        store.add_by_id(name, id.to_string()).unwrap();
+        let output = store.get(name).unwrap();
+        assert!(output.data.is_none(), "there should be no data");
+        assert_eq!(output.id, Some(id.to_string()));
+    }
+
     #[test]
     fn get_bad_database() -> Result<(), MTTError> {
         let store = Store::new();