[test] ensure static rendering finishes when a tile can't be loaded

test/api/render_missing.cpp

@@ -0,0 +1,63 @@
+#include "../fixtures/util.hpp"
+#include "../fixtures/fixture_log_observer.hpp"
+
+#include <mbgl/map/map.hpp>
+#include <mbgl/platform/default/headless_view.hpp>
+#include <mbgl/platform/default/headless_display.hpp>
+#include <mbgl/storage/default_file_source.hpp>
+#include <mbgl/util/image.hpp>
+#include <mbgl/util/io.hpp>
+
+#include <future>
+
+TEST(API, RenderMissingTile) {
+    using namespace mbgl;
+
+    const auto style = util::read_file("test/fixtures/api/water_missing_tiles.json");
+
+    auto display = std::make_shared<mbgl::HeadlessDisplay>();
+    HeadlessView view(display, 1, 256, 512);
+#ifdef MBGL_ASSET_ZIP
+    // Regenerate with `cd test/fixtures/api/ && zip -r assets.zip assets/`
+    DefaultFileSource fileSource(":memory:", "test/fixtures/api/assets.zip");
+#else
+    DefaultFileSource fileSource(":memory:", "test/fixtures/api/assets");
+#endif
+
+    Log::setObserver(std::make_unique<FixtureLogObserver>());
+
+    Map map(view, fileSource, MapMode::Still);
+
+    std::string message;
+
+    // This host does not respond (== connection error).
+    map.setStyleJSON(style, "");
+    std::promise<void> promise;
+    map.renderStill([&promise, &message](std::exception_ptr err, PremultipliedImage&&) {
+        ASSERT_TRUE(err.operator bool());
+        try {
+            std::rethrow_exception(err);
+        } catch (const std::exception& ex) {
+            message = ex.what();
+#ifdef MBGL_HTTP_NSURL
+            EXPECT_STREQ("Could not connect to the server.", ex.what());
+#elif MBGL_HTTP_CURL
+            const char* prefix = "Couldn't connect to server:";
+            EXPECT_EQ(0, strncmp(prefix, ex.what(), strlen(prefix))) << "Full message is: \""
+                                                                     << ex.what() << "\"";
+#else
+            FAIL();
+#endif
+        }
+        promise.set_value();
+    });
+    promise.get_future().get();
+
+    auto observer = Log::removeObserver();
+    auto flo = dynamic_cast<FixtureLogObserver*>(observer.get());
+    EXPECT_EQ(1, flo->count(FixtureLog::Message(
+                     EventSeverity::Error, Event::Style, -1,
+                     std::string("Failed to load tile 0/0/0 for source mapbox: " + message))));
+    auto unchecked = flo->unchecked();
+    EXPECT_TRUE(unchecked.empty()) << unchecked;
+}

test/fixtures/api/assets/streets_missing_tiles.json

@@ -0,0 +1,14 @@
+{
+  "bounds": [ -180, -85.0511, 180, 85.0511 ],
+  "center": [ 0, 0, 0 ],
+  "description": "",
+  "format": "pbf",
+  "id": "streets",
+  "maskLevel": 8,
+  "maxzoom": 15,
+  "minzoom": 0,
+  "name": "Streets",
+  "scheme": "xyz",
+  "tilejson": "2.0.0",
+  "tiles": [ "http://127.0.0.1:3001/{z}-{x}-{y}.vector.pbf" ]
+}

test/fixtures/api/water_missing_tiles.json

@@ -0,0 +1,25 @@
+{
+  "version": 8,
+  "name": "Water",
+  "sources": {
+    "mapbox": {
+      "type": "vector",
+      "url": "asset://streets_missing_tiles.json"
+    }
+  },
+  "layers": [{
+    "id": "background",
+    "type": "background",
+    "paint": {
+      "background-color": "red"
+    }
+  }, {
+    "id": "water",
+    "type": "fill",
+    "source": "mapbox",
+    "source-layer": "water",
+    "paint": {
+      "fill-color": "blue"
+    }
+  }]
+}

test/test.gypi

@@ -41,6 +41,7 @@
         'api/annotations.cpp',
         'api/api_misuse.cpp',
         'api/repeated_render.cpp',
+        'api/render_missing.cpp',
         'api/set_style.cpp',
         'api/custom_layer.cpp',