[tests] Add utests for AsyncTask

test/miscellaneous/async_task.cpp

@@ -0,0 +1,129 @@
+#include <mbgl/util/async_task.hpp>
+#include <mbgl/util/run_loop.hpp>
+#include <mbgl/util/thread.hpp>
+
+#include "../fixtures/util.hpp"
+
+#include <vector>
+
+using namespace mbgl::util;
+
+namespace {
+
+class TestWorker {
+public:
+    TestWorker(AsyncTask *async_)
+        : async(async_) {}
+
+    void run() {
+        for (unsigned i = 0; i < 100000; ++i) {
+            async->send();
+        }
+    }
+
+    void runWithCallback(std::function<void()> cb) {
+        for (unsigned i = 0; i < 100000; ++i) {
+            async->send();
+        }
+
+        cb();
+    }
+
+private:
+    AsyncTask *async;
+};
+
+}
+
+TEST(AsyncTask, RequestCoalescing) {
+    RunLoop loop;
+
+    unsigned count = 0;
+    AsyncTask async([&count] { ++count; });
+    async.unref();
+
+    async.send();
+    async.send();
+    async.send();
+    async.send();
+    async.send();
+
+    loop.runOnce();
+
+    EXPECT_EQ(count, 1);
+}
+
+TEST(AsyncTask, DestroyShouldNotRunQueue) {
+    RunLoop loop;
+
+    unsigned count = 0;
+    auto async = std::make_unique<AsyncTask>([&count] { ++count; });
+
+    async->send();
+    async.reset();
+
+    EXPECT_EQ(count, 0);
+}
+
+TEST(AsyncTask, RequestCoalescingMultithreaded) {
+    RunLoop loop;
+
+    unsigned count = 0;
+    AsyncTask async([&count] { ++count; });
+    async.unref();
+
+    std::vector<std::unique_ptr<Thread<TestWorker>>> threads;
+    ThreadContext context = {"Test", ThreadType::Map, ThreadPriority::Regular};
+
+    unsigned numThreads = 50;
+    for (unsigned i = 0; i < numThreads; ++i) {
+        std::unique_ptr<Thread<TestWorker>> thread =
+            std::make_unique<Thread<TestWorker>>(context, &async);
+
+        thread->invoke(&TestWorker::run);
+        threads.push_back(std::move(thread));
+    }
+
+    // Join all the threads
+    threads.clear();
+
+    loop.runOnce();
+
+    EXPECT_EQ(count, 1);
+}
+
+TEST(AsyncTask, ThreadSafety) {
+    RunLoop loop;
+
+    unsigned count = 0;
+    AsyncTask async([&count] { ++count; });
+    async.unref();
+
+    unsigned numThreads = 50;
+
+    auto callback = [&] {
+        if (!--numThreads) {
+            loop.stop();
+        }
+    };
+
+    std::vector<std::unique_ptr<Thread<TestWorker>>> threads;
+    std::vector<std::unique_ptr<mbgl::WorkRequest>> requests;
+    ThreadContext context = {"Test", ThreadType::Map, ThreadPriority::Regular};
+
+    for (unsigned i = 0; i < numThreads; ++i) {
+        std::unique_ptr<Thread<TestWorker>> thread =
+            std::make_unique<Thread<TestWorker>>(context, &async);
+
+        requests.push_back(
+            thread->invokeWithCallback(&TestWorker::runWithCallback, callback));
+
+        threads.push_back(std::move(thread));
+    }
+
+    loop.run();
+
+    // We expect here more than 1 but 1 would also be
+    // a valid result, although very unlikely (I hope).
+    EXPECT_GT(count, 1);
+}

test/test.gypi

@@ -45,6 +45,7 @@
         'api/set_style.cpp',
 
 
+        'miscellaneous/async_task.cpp',
         'miscellaneous/clip_ids.cpp',
         'miscellaneous/binpack.cpp',
         'miscellaneous/bilinear.cpp',