Refactor ledger replay logic (RIPD-1547):

Also switch to use ReadView for TxQ updates.

src/test/app/LedgerReplay_test.cpp

@@ -0,0 +1,62 @@
+ //------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2018 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <test/jtx.h>
+#include <ripple/app/ledger/BuildLedger.h>
+#include <ripple/app/ledger/LedgerMaster.h>
+#include <ripple/app/ledger/LedgerReplay.h>
+
+namespace ripple {
+namespace test {
+
+struct LedgerReplay_test : public beast::unit_test::suite
+{
+    void run() override
+    {
+        testcase("Replay ledger");
+
+        using namespace jtx;
+
+        // Build a ledger normally
+        auto const alice = Account("alice");
+        auto const bob = Account("bob");
+
+        Env env(*this);
+        env.fund(XRP(100000), alice, bob);
+        env.close();
+
+        LedgerMaster& ledgerMaster = env.app().getLedgerMaster();
+        auto const lastClosed = ledgerMaster.getClosedLedger();
+        auto const lastClosedParent =
+            ledgerMaster.getLedgerByHash(lastClosed->info().parentHash);
+
+        auto const replayed = buildLedger(
+            LedgerReplay(lastClosedParent,lastClosed),
+            tapNO_CHECK_SIGN,
+            env.app(),
+            env.journal);
+
+        BEAST_EXPECT(replayed->info().hash == lastClosed->info().hash);
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(LedgerReplay,app,ripple);
+
+} // test
+} // ripple