Factor out peer node creation in network stress test

This will be useful later when stopping and restarting peer nodes in mailbox send test.  I added a getter to ``P2PService`` to get its public keyring.

network/src/main/java/io/bitsquare/p2p/P2PService.java

@@ -775,6 +775,11 @@ public class P2PService implements SetupListener, MessageListener, ConnectionLis
         return peerManager;
     }
 
+    @VisibleForTesting
+    public KeyRing getKeyRing() {
+        return optionalKeyRing.get();
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////
     // Private
     ///////////////////////////////////////////////////////////////////////////////////////////

network/src/test/java/io/bitsquare/p2p/network/NetworkStressTest.java

@@ -140,24 +140,9 @@ public class NetworkStressTest {
         for (int p = 0; p < nPeers; p++) {
             // peer network port
             final int peerPort = Utils.findFreeSystemPort();
-
-            // peer data directories
-            final File peerDir = new File(testDataDir.toFile(), String.format("peer-%06d", p));
-            final File peerTorDir = new File(peerDir, "tor");
-            final File peerStorageDir = new File(peerDir, "db");
-            final File peerKeysDir = new File(peerDir, "keys");
-            //noinspection ResultOfMethodCallIgnored
-            peerKeysDir.mkdirs();  // needed for creating the key ring
-
-            // peer keys
-            final KeyStorage peerKeyStorage = new KeyStorage(peerKeysDir);
-            final KeyRing peerKeyRing = new KeyRing(peerKeyStorage);
-            peerPKRings.add(peerKeyRing.getPubKeyRing());
-            final EncryptionService peerEncryptionService = new EncryptionService(peerKeyRing);
-
             // create, save and start peer
-            final P2PService peer = new P2PService(seedNodesRepository, peerPort, peerTorDir, useLocalhost,
+            final P2PService peer = createPeerNode(p, peerPort, useLocalhost, seedNodesRepository);
-                    REGTEST_NETWORK_ID, peerStorageDir, new Clock(), peerEncryptionService, peerKeyRing);
+            peerPKRings.add(peer.getKeyRing().getPubKeyRing());
             peerNodes.add(peer);
             peer.start(new PeerServiceListener(localServicesLatch, localServicesFailed));
         }
@@ -185,6 +170,25 @@ public class NetworkStressTest {
         return new NodeAddress("localhost", port);
     }
 
+    @NotNull
+    private P2PService createPeerNode(int n, int port, boolean useLocalhost, SeedNodesRepository seedNodesRepository) {
+        // peer data directories
+        final File peerDir = new File(testDataDir.toFile(), String.format("peer-%06d", n));
+        final File peerTorDir = new File(peerDir, "tor");
+        final File peerStorageDir = new File(peerDir, "db");
+        final File peerKeysDir = new File(peerDir, "keys");
+        //noinspection ResultOfMethodCallIgnored
+        peerKeysDir.mkdirs();  // needed for creating the key ring
+
+        // peer keys
+        final KeyStorage peerKeyStorage = new KeyStorage(peerKeysDir);
+        final KeyRing peerKeyRing = new KeyRing(peerKeyStorage);
+        final EncryptionService peerEncryptionService = new EncryptionService(peerKeyRing);
+
+        return new P2PService(seedNodesRepository, port, peerTorDir, useLocalhost,
+                REGTEST_NETWORK_ID, peerStorageDir, new Clock(), peerEncryptionService, peerKeyRing);
+    }
+
     @After
     public void tearDown() throws InterruptedException, IOException {
         /** A barrier to wait for concurrent shutdown of services. */