Added not table return.

src/lib.rs

@@ -31,8 +31,10 @@ impl Query {
             .read()
             .await
             .to_vec();
-        let idx = tbls.binary_search_by(|t| t.name.cmp(&name)).unwrap();
-        Ok(Some(tbls[idx].clone()))
+        match tbls.binary_search_by(|t| t.name.cmp(&name)) {
+            Ok(idx) => Ok(Some(tbls[idx].clone())),
+            Err(_) => Ok(None),
+        }
     }
 
     async fn tables(&self, ctx: &Context<'_>) -> Vec<Table> {
@@ -109,6 +111,14 @@ mod queries {
         support::compare(&db, &output, &expected);
     }
 
+    #[async_std::test]
+    async fn list_no_table() {
+        let db = Database::new();
+        let output = db.execute(r#"{table(name: "slade"){name}}"#).await;
+        let expected = r#"{"data":{"table":null}}"#;
+        support::compare(&db, &output, &expected);
+    }
+
     #[async_std::test]
     async fn list_tables() {
         let db = Database::new();