add tests for Labels and LabeledFrames (#460)

* Add tests
- test `Labels.remove_untracked_instances()` for both cases of `remove_empty_frames: bool`
-test `LabeledFrames.remove_untracked()` for both user-labeled and predicted frames

tests/io/test_dataset.py

@@ -1420,3 +1420,41 @@ def test_split(centered_pair_predictions):
     assert len(labels_a) == 1
     assert len(labels_b) == 1
     assert labels_a[0] == labels_b[0]
+
+
+def test_remove_untracked_instances(min_tracks_2node_labels):
+    """Test removal of untracked instances and empty frames.
+
+    Args:
+        min_tracks_2node_labels: Labels object which contains user labeled frames with
+        tracked instances.
+    """
+    # XXX(LM): only test user_labeled instances
+    # XXX(LM): can we ensure that the datasets will remain unchanged?
+    labels = min_tracks_2node_labels
+
+    # XXX(LM): should I remove multiple tracks and frames?
+    # XXX(LM): if len(labels.labeled_frames)==1,
+    # XXX(LM)       then will not properly test lf.remove_untracked()
+    # Preprocessing
+    labels.labeled_frames[0].instances[0].track = None
+    labels.labeled_frames[-1].instances = []
+    assert any(
+        [(inst.track is None) for lf in labels.labeled_frames for inst in lf.instances]
+    )
+    assert any([(len(lf.instances) == 0) for lf in labels.labeled_frames])
+
+    # Test function with remove_empty_frames=False
+    labels.remove_untracked_instances(remove_empty_frames=False)
+    assert all(
+        [
+            (inst.track is not None)
+            for lf in labels.labeled_frames
+            for inst in lf.instances
+        ]
+    )
+    assert any([(len(lf.instances) == 0) for lf in labels.labeled_frames])
+
+    # Test function with remove_empty_frames=True
+    labels.remove_untracked_instances(remove_empty_frames=True)
+    assert all([(len(lf.instances) > 0) for lf in labels.labeled_frames])

tests/test_instance.py

@@ -477,3 +477,33 @@ def test_labeledframe_instance_counting(min_labels, centered_pair_predictions):
     assert lf.n_tracked_instances == 0
     assert len(lf.tracked_instances) == 0
     assert not lf.has_tracked_instances
+
+
+def test_labeledframe_remove_untracked(
+    min_tracks_2node_labels: "Labels", centered_pair_predictions: "Labels"
+):
+    """Test removal of untracked instances on both user-labeled and predicted frames.
+
+    Args:
+        min_tracks_2node_labels: Labels object which contains user labeled frames with tracked instances.
+        centered_pair_predictions: Labels object which contains predicted frames with tracked instances.
+    """
+    # Load user-labeled frames.
+    lf = min_tracks_2node_labels.labeled_frames[0]
+    assert any([type(inst) == Instance for inst in lf.instances])
+
+    lf.instances[0].track = None
+    assert any([(inst.track is None) for inst in lf.instances])
+
+    lf.remove_untracked()
+    assert all([(inst.track is not None) for inst in lf.instances])
+
+    # Load predicted frames.
+    lf = centered_pair_predictions.labeled_frames[0]
+    assert any([type(inst) == PredictedInstance for inst in lf.instances])
+
+    lf.instances[0].track = None
+    assert any([(inst.track is None) for inst in lf.instances])
+
+    lf.remove_untracked()
+    assert all([(inst.track is not None) for inst in lf.instances])