Rate limit outgoing JOIN messages (#3115)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>
Co-authored-by: Tal Neoran <talneoran@gmail.com>

tests/src/RatelimitBucket.cpp

@@ -0,0 +1,46 @@
+#include "util/RatelimitBucket.hpp"
+
+#include <gtest/gtest.h>
+#include <QApplication>
+#include <QDebug>
+#include <QtConcurrent>
+
+#include <chrono>
+#include <thread>
+
+using namespace chatterino;
+
+TEST(RatelimitBucket, BatchTwoParts)
+{
+    const int cooldown = 100;
+    int n = 0;
+    auto cb = [&n](QString msg) {
+        qDebug() << msg;
+        ++n;
+    };
+    auto bucket = std::make_unique<RatelimitBucket>(5, cooldown, cb, nullptr);
+    bucket->send("1");
+    EXPECT_EQ(n, 1);
+
+    bucket->send("2");
+    EXPECT_EQ(n, 2);
+
+    bucket->send("3");
+    EXPECT_EQ(n, 3);
+
+    bucket->send("4");
+    EXPECT_EQ(n, 4);
+
+    bucket->send("5");
+    EXPECT_EQ(n, 5);
+
+    bucket->send("6");
+    // Rate limit reached, n will not have changed yet. If we wait for the cooldown to run, n should have changed
+    EXPECT_EQ(n, 5);
+
+    QCoreApplication::processEvents();
+    std::this_thread::sleep_for(std::chrono::milliseconds{cooldown});
+    QCoreApplication::processEvents();
+
+    EXPECT_EQ(n, 6);
+}