add custom imagery visual test

test/fixtures/headless/pois.json

@@ -0,0 +1,26 @@
+{
+  "version": 7,
+  "name": "POIs",
+  "sources": {
+    "mapbox": {
+      "type": "vector",
+      "url": "asset://TEST_DATA/fixtures/tiles/streets.json"
+    }
+  },
+  "layers": [{
+    "id": "background",
+    "type": "background",
+    "paint": {
+      "background-color": "#CCCCCC"
+    }
+  }, {
+    "id": "pois",
+    "type": "symbol",
+    "source": "mapbox",
+    "source-layer": "poi_label",
+    "filter": ["in", "maki", "cafe", "bakery"],
+    "layout": {
+      "icon-image": "{maki}"
+    }
+  }]
+}

test/headless/custom_sprites.cpp

@@ -0,0 +1,61 @@
+#include "../fixtures/util.hpp"
+#include "../fixtures/fixture_log_observer.hpp"
+
+#include <mbgl/map/map.hpp>
+#include <mbgl/map/still_image.hpp>
+#include <mbgl/util/image.hpp>
+#include <mbgl/annotation/sprite_image.hpp>
+
+#include <mbgl/util/io.hpp>
+
+#include <mbgl/platform/default/headless_view.hpp>
+#include <mbgl/platform/default/headless_display.hpp>
+#include <mbgl/storage/default_file_source.hpp>
+
+#include <future>
+
+using namespace mbgl;
+
+TEST(Headless, CustomSpriteImages) {
+    FixtureLog log;
+
+    auto display = std::make_shared<mbgl::HeadlessDisplay>();
+    HeadlessView view(display, 1);
+    view.resize(256, 256);
+    DefaultFileSource fileSource(nullptr);
+
+    const auto style = util::read_file("test/fixtures/headless/pois.json");
+
+    Map map(view, fileSource, MapMode::Still);
+
+    map.setLatLngZoom(LatLng{ 52.499167, 13.418056 }, 15);
+
+    map.setStyleJSON(style, "test/suite");
+    map.setSprite("cafe",
+                  std::make_shared<SpriteImage>(12, 12, 1, std::string(12 * 12 * 4, '\xFF')));
+    std::promise<std::unique_ptr<const StillImage>> promise;
+    map.renderStill([&promise](std::exception_ptr error, std::unique_ptr<const StillImage> image) {
+        if (error) {
+            promise.set_exception(error);
+        } else {
+            promise.set_value(std::move(image));
+        }
+    });
+    auto result = promise.get_future().get();
+    ASSERT_EQ(256, result->width);
+    ASSERT_EQ(256, result->height);
+
+    EXPECT_EQ(
+        21u,
+        log.count({
+            EventSeverity::Info, Event::Sprite, int64_t(-1), "Can't find sprite named 'bakery'",
+        }));
+
+    // const size_t bytes = result->width * result->height * 4;
+    // const auto hash = test::crc64(reinterpret_cast<const char*>(result->pixels.get()), bytes);
+    // EXPECT_EQ(0xC40A4BCD76AEC564u, hash) << std::hex << hash;
+
+    // const std::string png = util::compress_png(result->width, result->height,
+    // result->pixels.get());
+    // util::write_file("test/fixtures/headless/1.actual.png", png);
+}

test/headless/headless.cpp

@@ -150,7 +150,11 @@ TEST_P(HeadlessTest, render) {
         map.setLatLngZoom(mbgl::LatLng(latitude, longitude), zoom);
         map.setBearing(bearing);
 
-        map.renderStill([&](std::exception_ptr, std::unique_ptr<const StillImage> image) {
+        map.renderStill([&](std::exception_ptr error, std::unique_ptr<const StillImage> image) {
+            if (error) {
+                promise.set_exception(error);
+                return;
+            }
             const std::string png = util::compress_png(image->width, image->height, image->pixels.get());
             util::write_file("test/suite/tests/" + base + "/" + name +  "/actual.png", png);
             promise.set_value();

test/test.gypi

@@ -46,6 +46,7 @@
         'api/repeated_render.cpp',
         'api/set_style.cpp',
 
+        'headless/custom_sprites.cpp',
         'headless/headless.cpp',
 
         'miscellaneous/clip_ids.cpp',