Add unit tests for addPointAnnotations()

This test would have caught #1874

test/api/annotations.cpp

@@ -0,0 +1,36 @@
+#include "../fixtures/fixture_log_observer.hpp"
+#include "../fixtures/mock_file_source.hpp"
+#include "../fixtures/util.hpp"
+
+#include <mbgl/annotation/point_annotation.hpp>
+#include <mbgl/map/map.hpp>
+#include <mbgl/map/still_image.hpp>
+#include <mbgl/platform/default/headless_display.hpp>
+#include <mbgl/platform/default/headless_view.hpp>
+
+#include <future>
+#include <vector>
+
+TEST(API, PointAnnotation) {
+    using namespace mbgl;
+
+    auto display = std::make_shared<mbgl::HeadlessDisplay>();
+    HeadlessView view(display, 1);
+
+    MockFileSource fileSource(MockFileSource::Success, "");
+
+    Map map(view, fileSource, MapMode::Still);
+    map.setStyleURL("test/fixtures/resources/style.json");
+
+    std::vector<PointAnnotation> points;
+    points.emplace_back(PointAnnotation({ 50.0, 50.0 }, "default_marker"));
+
+    map.addPointAnnotations(points);
+
+    std::promise<bool> promise;
+    map.renderStill([&promise](std::exception_ptr, std::unique_ptr<const StillImage>) {
+        promise.set_value(true);
+    });
+
+    promise.get_future().get();
+}