Implement base for nextgen rpc subsystem (#487)

Fixes #494

unittests/rpc/handlers/DefaultProcessorTests.cpp

@@ -0,0 +1,66 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2023, the clio developers.
+
+    Permission to use, copy, modify, and 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 <rpc/handlers/impl/FakesAndMocks.h>
+#include <util/Fixtures.h>
+
+#include <rpc/common/impl/Processors.h>
+
+#include <boost/json/parse.hpp>
+
+using namespace testing;
+using namespace std;
+
+using namespace RPCng;
+using namespace RPCng::validation;
+using namespace unittests::detail;
+
+namespace json = boost::json;
+
+class RPCDefaultProcessorTest : public NoLoggerFixture
+{
+};
+
+TEST_F(RPCDefaultProcessorTest, ValidInput)
+{
+    HandlerMock handler;
+    RPCng::detail::DefaultProcessor<HandlerMock> processor;
+
+    auto const input = json::parse(R"({ "something": "works" })");
+    auto const spec = RpcSpec{{"something", Required{}}};
+    auto const data = InOutFake{"works"};
+    EXPECT_CALL(handler, spec()).WillOnce(ReturnRef(spec));
+    EXPECT_CALL(handler, process(Eq(data))).WillOnce(Return(data));
+
+    auto const ret = processor(handler, input);
+    ASSERT_TRUE(ret);  // no error
+}
+
+TEST_F(RPCDefaultProcessorTest, InvalidInput)
+{
+    HandlerMock handler;
+    RPCng::detail::DefaultProcessor<HandlerMock> processor;
+
+    auto const input = json::parse(R"({ "other": "nope" })");
+    auto const spec = RpcSpec{{"something", Required{}}};
+    EXPECT_CALL(handler, spec()).WillOnce(ReturnRef(spec));
+
+    auto const ret = processor(handler, input);
+    ASSERT_FALSE(ret);  // returns error
+}