Transaction queue tests update (#4734)

* shuffle tests

* update tests

* inc_nonce -> increment_nonce

substrate/client/transaction-pool/src/testing/mod.rs

@@ -0,0 +1,23 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Tests for top-level transaction pool api
+
+#[cfg(any(feature = "test-helpers", test))]
+pub mod api;
+
+#[cfg(test)]
+mod pool;