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/Digraph_test.cpp

@@ -0,0 +1,100 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2017 Ripple Labs Inc.
+
+    Permission target 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/Digraph.h>
+#include <vector>
+#include <string>
+
+namespace ripple {
+namespace test {
+
+class Digraph_test : public beast::unit_test::suite
+{
+public:
+
+    void
+    run() override
+    {
+        using namespace csf;
+        using Graph = Digraph<char,std::string>;
+        Graph graph;
+
+        BEAST_EXPECT(!graph.connected('a', 'b'));
+        BEAST_EXPECT(!graph.edge('a', 'b'));
+        BEAST_EXPECT(!graph.disconnect('a', 'b'));
+
+        BEAST_EXPECT(graph.connect('a', 'b', "foobar"));
+        BEAST_EXPECT(graph.connected('a', 'b'));
+        BEAST_EXPECT(*graph.edge('a', 'b') == "foobar");
+
+        BEAST_EXPECT(!graph.connect('a', 'b', "repeat"));
+        BEAST_EXPECT(graph.disconnect('a', 'b'));
+        BEAST_EXPECT(graph.connect('a', 'b', "repeat"));
+        BEAST_EXPECT(graph.connected('a', 'b'));
+        BEAST_EXPECT(*graph.edge('a', 'b') == "repeat");
+
+
+        BEAST_EXPECT(graph.connect('a', 'c', "tree"));
+
+        {
+            std::vector<std::tuple<char, char, std::string>> edges;
+
+            for (auto const & edge : graph.outEdges('a'))
+            {
+                edges.emplace_back(edge.source, edge.target, edge.data);
+            }
+
+            std::vector<std::tuple<char, char, std::string>> expected;
+            expected.emplace_back('a', 'b', "repeat");
+            expected.emplace_back('a', 'c', "tree");
+            BEAST_EXPECT(edges == expected);
+            BEAST_EXPECT(graph.outDegree('a') == expected.size());
+        }
+
+        BEAST_EXPECT(graph.outEdges('r').size() == 0);
+        BEAST_EXPECT(graph.outDegree('r') == 0);
+        BEAST_EXPECT(graph.outDegree('c') == 0);
+
+        // only 'a' has out edges
+        BEAST_EXPECT(graph.outVertices().size() == 1);
+        std::vector<char> expected = {'b','c'};
+
+        BEAST_EXPECT((graph.outVertices('a') == expected));
+        BEAST_EXPECT(graph.outVertices('b').size() == 0);
+        BEAST_EXPECT(graph.outVertices('c').size() == 0);
+        BEAST_EXPECT(graph.outVertices('r').size() == 0);
+
+        std::stringstream ss;
+        graph.saveDot(ss, [](char v) { return v;});
+        std::string expectedDot = "digraph {\n"
+        "a -> b;\n"
+        "a -> c;\n"
+        "}\n";
+        BEAST_EXPECT(ss.str() == expectedDot);
+
+
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(Digraph, test, ripple);
+
+}  // namespace test
+}  // namespace ripple