added add_cache function.

src/morethantext/mod.rs

@@ -5,6 +5,10 @@ use error::DBError;
 
 const DATA: &str = "data";
 
+enum CacheEntry {
+    Raw(String),
+}
+
 #[derive(Clone)]
 pub struct MoreThanText;
 
@@ -23,6 +27,10 @@ impl MoreThanText {
         }
         Ok(Self {})
     }
+
+    async fn add_entry(&self, _entry: CacheEntry) -> String {
+        "fred".to_string()
+    }
 }
 
 #[cfg(test)]
@@ -64,3 +72,19 @@ mod init {
         };
     }
 }
+
+#[cfg(test)]
+mod cache {
+    use super::*;
+    use tempfile::tempdir;
+
+    #[async_std::test]
+    async fn  add_entry() {
+        let dir = tempdir().unwrap();
+        let db = MoreThanText::new(dir.path().to_str().unwrap()).await.unwrap();
+        let data = CacheEntry::Raw("something".to_string());
+        db.add_entry(data).await;
+        drop(db);
+        dir.close().unwrap();
+    }
+}