tabify tests (#3220)

* tabify tests

* move mod tests; up

polkadot/node/network/approval-distribution/src/lib.rs

@@ -20,10 +20,6 @@
 
 #![warn(missing_docs)]
 
-#[cfg(test)]
-mod tests;
-
-
 use std::collections::{BTreeMap, HashMap, HashSet, hash_map};
 use futures::{channel::oneshot, FutureExt as _};
 use polkadot_primitives::v1::{
@@ -47,6 +43,9 @@ use polkadot_node_network_protocol::{
 	PeerId, View, v1 as protocol_v1, UnifiedReputationChange as Rep,
 };
 
+#[cfg(test)]
+mod tests;
+
 const LOG_TARGET: &str = "parachain::approval-distribution";
 
 const COST_UNEXPECTED_MESSAGE: Rep = Rep::CostMinor("Peer sent an out-of-view assignment or approval");