Added file errors to update entry.

src/morethantext/mod.rs

@@ -99,9 +99,14 @@ impl MoreThanText {
             Ok(_) => (),
             Err(err) => return Err(err),
         }
-        write(Path::new(&self.dir).join(&id), entry.to_bytes())
-            .await
-            .unwrap();
+        match write(Path::new(&self.dir).join(&id), entry.to_bytes()).await {
+            Ok(_) => (),
+            Err(err) => {
+                let mut error = DBError::new("data write");
+                error.add_source(err);
+                return Err(error);
+            }
+        }
         let mut cache = self.cache.lock().await;
         cache.insert(id.to_string(), entry);
         Ok(())
@@ -262,6 +267,31 @@ mod cache {
             Err(err) => assert_eq!(err.to_string(), "cache entry not found"),
         }
     }
+
+    #[async_std::test]
+    async fn update_bad_file() {
+        let mtt = MTT::new().await;
+        let msg = "could not write to file";
+        let id = mtt
+            .db
+            .add_entry(CacheEntry::Raw("fleeting".to_string()))
+            .await
+            .unwrap();
+        mtt.create_io_error().await;
+        match mtt
+            .db
+            .update_entry(&id, CacheEntry::Raw("failure".to_string()))
+            .await
+        {
+            Ok(_) => assert!(false, "This should produce a write failure."),
+            Err(err) => {
+                assert_eq!(err.to_string(), "data write");
+                assert!(err.source().is_some(), "Must include the source error.");
+                let err_msg = err.source().unwrap().to_string();
+                assert!(err_msg.contains(msg), "'{}' not in '{}'", msg, err_msg);
+            }
+        }
+    }
 }
 
 #[cfg(test)]