Redesign CSF framework (RIPD-1361):

- Separate `Scheduler` from `BasicNetwork`.
- Add an event/collector framework for monitoring invariants and calculating statistics.
- Allow distinct network and trust connections between Peers.
- Add a simple routing strategy to support broadcasting arbitrary messages.
- Add a common directed graph (`Digraph`) class for representing network and trust topologies.
- Add a `PeerGroup` class for simpler specification of the trust and network topologies.
- Add a `LedgerOracle` class to ensure distinct ledger histories and simplify branch checking.
- Add a `Submitter` to send transactions in at fixed or random intervals to fixed or random peers.

Co-authored-by: Joseph McGee

src/test/csf/Scheduler_test.cpp

@@ -0,0 +1,89 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2017 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 <BeastConfig.h>
+#include <ripple/beast/unit_test.h>
+#include <test/csf/Scheduler.h>
+#include <set>
+
+namespace ripple {
+namespace test {
+
+class Scheduler_test : public beast::unit_test::suite
+{
+public:
+
+    void
+    run() override
+    {
+        using namespace std::chrono_literals;
+        csf::Scheduler scheduler;
+        std::set<int> seen;
+
+        scheduler.in(1s, [&]{ seen.insert(1);});
+        scheduler.in(2s, [&]{ seen.insert(2);});
+        auto token = scheduler.in(3s, [&]{ seen.insert(3);});
+        scheduler.at(scheduler.now() + 4s, [&]{ seen.insert(4);});
+        scheduler.at(scheduler.now() + 8s, [&]{ seen.insert(8);});
+
+        auto start = scheduler.now();
+
+        // Process first event
+        BEAST_EXPECT(seen.empty());
+        BEAST_EXPECT(scheduler.step_one());
+        BEAST_EXPECT(seen == std::set<int>({1}));
+        BEAST_EXPECT(scheduler.now() == (start + 1s));
+
+        // No processing if stepping until current time
+        BEAST_EXPECT(scheduler.step_until(scheduler.now()));
+        BEAST_EXPECT(seen == std::set<int>({1}));
+        BEAST_EXPECT(scheduler.now() == (start + 1s));
+
+        // Process next event
+        BEAST_EXPECT(scheduler.step_for(1s));
+        BEAST_EXPECT(seen == std::set<int>({1,2}));
+        BEAST_EXPECT(scheduler.now() == (start + 2s));
+
+        // Don't process cancelled event, but advance clock
+        scheduler.cancel(token);
+        BEAST_EXPECT(scheduler.step_for(1s));
+        BEAST_EXPECT(seen == std::set<int>({1,2}));
+        BEAST_EXPECT(scheduler.now() == (start + 3s));
+
+        // Process until 3 seen ints
+        BEAST_EXPECT(scheduler.step_while([&]() { return seen.size() < 3; }));
+        BEAST_EXPECT(seen == std::set<int>({1,2,4}));
+        BEAST_EXPECT(scheduler.now() == (start + 4s));
+
+        // Process the rest
+        BEAST_EXPECT(scheduler.step());
+        BEAST_EXPECT(seen == std::set<int>({1,2,4,8}));
+        BEAST_EXPECT(scheduler.now() == (start + 8s));
+
+        // Process the rest again doesn't advance
+        BEAST_EXPECT(!scheduler.step());
+        BEAST_EXPECT(seen == std::set<int>({1,2,4,8}));
+        BEAST_EXPECT(scheduler.now() == (start + 8s));
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(Scheduler, test, ripple);
+
+}  // namespace test
+}  // namespace ripple