Making sure there's at least one admin. Fixing unit tests

crates/api/src/site.rs

@@ -477,6 +477,12 @@ impl Perform for LeaveAdmin {
 
     is_admin(&local_user_view)?;
 
+    // Make sure there isn't just one admin (so if one leaves, there will still be one left)
+    let admins = blocking(context.pool(), PersonViewSafe::admins).await??;
+    if admins.len() == 1 {
+      return Err(LemmyError::from_message("cannot_leave_admin"));
+    }
+
     let person_id = local_user_view.person.id;
     blocking(context.pool(), move |conn| {
       Person::leave_admin(conn, person_id)

crates/db_schema/src/aggregates/site_aggregates.rs

@@ -132,7 +132,12 @@ mod tests {
     let community_num_deleted = Community::delete(&conn, inserted_community.id).unwrap();
     assert_eq!(1, community_num_deleted);
 
-    let after_delete = SiteAggregates::read(&conn);
-    assert!(after_delete.is_err());
+    // Site should still exist, it can without a site creator.
+    let after_delete_creator = SiteAggregates::read(&conn);
+    assert!(after_delete_creator.is_ok());
+
+    Site::delete(&conn, 1).unwrap();
+    let after_delete_site = SiteAggregates::read(&conn);
+    assert!(after_delete_site.is_err());
   }
 }