[core] Add unit test for pausing & resuming database fs

test/storage/database_file_source.test.cpp

@@ -0,0 +1,25 @@
+#include <mbgl/storage/file_source_manager.hpp>
+#include <mbgl/storage/resource.hpp>
+#include <mbgl/storage/resource_options.hpp>
+#include <mbgl/test/util.hpp>
+#include <mbgl/util/run_loop.hpp>
+#include <mbgl/util/timer.hpp>
+
+#include <gtest/gtest.h>
+
+using namespace mbgl;
+
+TEST(DatabaseFileSource, PauseResume) {
+    util::RunLoop loop;
+
+    auto dbfs = FileSourceManager::get()->getFileSource(FileSourceType::Database, ResourceOptions{});
+    dbfs->pause();
+
+    const Resource res{Resource::Unknown, "http://127.0.0.1:3000/test", {}, Resource::LoadingMethod::CacheOnly};
+    auto req = dbfs->request(res, [&](const Response&) { loop.stop(); });
+
+    util::Timer resumeTimer;
+    resumeTimer.start(Milliseconds(5), Duration::zero(), [dbfs] { dbfs->resume(); });
+
+    loop.run();
+}