Added cache update function.

src/morethantext/mod.rs

@@ -61,6 +61,16 @@ impl MoreThanText {
             None => Err(DBError::new("cache entry not found")),
         }
     }
+
+    async fn update_entry(&self, id: &str, entry: CacheEntry) -> Result<(), DBError> {
+        match self.get_entry(id).await {
+            Ok(_) => (),
+            Err(err) => return Err(err),
+        }
+        let mut cache = self.cache.lock().await;
+        cache.insert(id.to_string(), entry);
+        Ok(())
+    }
 }
 
 #[cfg(test)]
@@ -157,4 +167,23 @@ mod cache {
             Err(err) => assert_eq!(err.to_string(), "cache entry not found"),
         }
     }
+
+    #[async_std::test]
+    async fn update_cache_entry() {
+        let mtt = MTT::new().await;
+        let id = mtt.db.add_entry(CacheEntry::Raw("same".to_string())).await;
+        let expected = "different";
+        mtt.db.update_entry(&id, CacheEntry::Raw(expected.to_string())).await.unwrap();
+        let output = mtt.db.get_entry(&id).await.unwrap();
+        assert_eq!(output.to_string(), expected);
+    }
+
+    #[async_std::test]
+    async fn update_bad_id() {
+        let mtt = MTT::new().await;
+        match mtt.db.update_entry("wilma", CacheEntry::Raw("wrong".to_string())).await {
+            Ok(_) => assert!(false, "Bad id should raise an error."),
+            Err(err) => assert_eq!(err.to_string(), "cache entry not found"),
+        }
+    }
 }