allow for multiple datasets for test data loader creation

Summary: Use all training dataset for export instead of just first. This is to support use cases where there is only a small amount of images per jsons but a number of jsons. Since calibration uses the first dataset, it is limited by the number of images in a single dataset.

Reviewed By: ppwwyyxx

Differential Revision: D28902673

fbshipit-source-id: f80146b02d2d1bc04703fbb21ef410f5e26ba64c

detectron2/data/build.py

@@ -397,8 +397,11 @@ def _test_loader_from_config(cfg, dataset_name, mapper=None):
  Uses the given `dataset_name` argument (instead of the names in cfg), because the
  standard practice is to evaluate each test set individually (not combining them).
  """
+ if isinstance(dataset_name, str):
+ dataset_name = [dataset_name]
+
  dataset = get_detection_dataset_dicts(
- [dataset_name],
+ dataset_name,
  filter_empty=False,
  proposal_files=[
  cfg.DATASETS.PROPOSAL_FILES_TEST[list(cfg.DATASETS.TEST).index(dataset_name)]