refactor: Move interval timer into a separate class (#1588)

For #442.

tests/unit/util/RepeatTests.cpp

@@ -0,0 +1,82 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, 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 "util/AsioContextTestFixture.hpp"
+#include "util/Repeat.hpp"
+#include "util/WithTimeout.hpp"
+
+#include <boost/asio/error.hpp>
+#include <boost/asio/executor_work_guard.hpp>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <functional>
+#include <ranges>
+#include <thread>
+#include <utility>
+
+using namespace util;
+using testing::AtLeast;
+
+struct RepeatTests : SyncAsioContextTest {
+    Repeat repeat{ctx};
+    testing::StrictMock<testing::MockFunction<void()>> handlerMock;
+
+    void
+    withRunningContext(std::function<void()> func)
+    {
+        tests::common::util::withTimeout(std::chrono::seconds{1000}, [this, func = std::move(func)]() {
+            auto workGuard = boost::asio::make_work_guard(ctx);
+            std::thread thread{[this]() { ctx.run(); }};
+            func();
+            workGuard.reset();
+            thread.join();
+        });
+    }
+};
+
+TEST_F(RepeatTests, CallsHandler)
+{
+    repeat.start(std::chrono::milliseconds{1}, handlerMock.AsStdFunction());
+    EXPECT_CALL(handlerMock, Call).Times(AtLeast(10));
+    runContextFor(std::chrono::milliseconds{20});
+}
+
+TEST_F(RepeatTests, StopsOnStop)
+{
+    withRunningContext([this]() {
+        repeat.start(std::chrono::milliseconds{1}, handlerMock.AsStdFunction());
+        EXPECT_CALL(handlerMock, Call).Times(AtLeast(1));
+        std::this_thread::sleep_for(std::chrono::milliseconds{10});
+        repeat.stop();
+    });
+}
+
+TEST_F(RepeatTests, RunsAfterStop)
+{
+    withRunningContext([this]() {
+        for ([[maybe_unused]] auto _ : std::ranges::iota_view(0, 2)) {
+            repeat.start(std::chrono::milliseconds{1}, handlerMock.AsStdFunction());
+            EXPECT_CALL(handlerMock, Call).Times(AtLeast(1));
+            std::this_thread::sleep_for(std::chrono::milliseconds{10});
+            repeat.stop();
+        }
+    });
+}