[test] allow aborting rendering after a timeout

test/api/annotations.cpp

@@ -19,11 +19,15 @@ std::shared_ptr<SpriteImage> namedMarker(const std::string &name) {
     return std::make_shared<SpriteImage>(image.width, image.height, 1.0, std::string(reinterpret_cast<char*>(image.data.get()), image.size()));
 }
 
+namespace {
+
 void checkRendering(Map& map, const char * name) {
     test::checkImage(std::string("test/fixtures/annotations/") + name + "/",
                      test::render(map), 0.0002, 0.1);
 }
 
+} // end namespace
+
 TEST(Annotations, PointAnnotation) {
     auto display = std::make_shared<mbgl::HeadlessDisplay>();
     HeadlessView view(display, 1);

test/fixtures/util.cpp

@@ -108,12 +108,20 @@ uint64_t crc64(const std::string& str) {
     return crc64(str.data(), str.size());
 }
 
-PremultipliedImage render(Map& map) {
+PremultipliedImage render(Map& map, std::chrono::milliseconds timeout) {
     std::promise<PremultipliedImage> promise;
     map.renderStill([&](std::exception_ptr, PremultipliedImage&& image) {
         promise.set_value(std::move(image));
     });
-    return promise.get_future().get();
+
+    // Limit maximum wait time.
+    auto future = promise.get_future();
+    if (future.wait_for(timeout) != std::future_status::ready) {
+        // Alas, we didn't get the promised future :(
+        Log::Error(Event::Image, "Failed to generate image within %dms", timeout.count());
+        return { 0, 0 };
+    }
+    return future.get();
 }
 
 void checkImage(const std::string& base,

test/fixtures/util.hpp

@@ -3,6 +3,7 @@
 
 #include <mbgl/util/image.hpp>
 
+#include <chrono>
 #include <cstdint>
 
 #include <gtest/gtest.h>
@@ -35,13 +36,13 @@ private:
 uint64_t crc64(const char*, size_t);
 uint64_t crc64(const std::string&);
 
-PremultipliedImage render(Map&);
+PremultipliedImage render(Map&,
+                          std::chrono::milliseconds timeout = std::chrono::milliseconds(1000));
 
 void checkImage(const std::string& base,
                 const PremultipliedImage& actual,
                 double imageThreshold = 0,
                 double pixelThreshold = 0);
-
 }
 }