[ios, macos] Fixed MGLMapSnapshotter test crash

Fixed a crash in MGLDocumentationExampleTests caused by an asynchronous snapshot call that the test wasn’t waiting on, compounded by the use of a style that requires an access token (as opposed to the one-liner style that uses no remote resources. Employed some Swiftisms to fulfill expectations without making the example code look weird.

1 files changed, 4 insertions, 4 deletions

diff --git a/platform/darwin/src/MGLMapSnapshotter.h b/platform/darwin/src/MGLMapSnapshotter.h
index fc68204a7d..426ab1bb00 100644
--- a/platform/darwin/src/MGLMapSnapshotter.h
+++ b/platform/darwin/src/MGLMapSnapshotter.h
@@ -145,11 +145,11 @@ typedef void (^MGLMapSnapshotCompletionHandler)(MGLMapSnapshot* _Nullable snapsh
  
  let snapshotter = MGLMapSnapshotter(options: options)
  snapshotter.start { (snapshot, error) in
-     if error != nil {
-         // error handler
-     } else {
-         // image handler
+     if let error = error {
+         fatalError(error.localizedDescription)
      }
+     
+     image = snapshot?.image
  }
  ```
  */