add gfl loss unit test

tests/test_models/test_loss/test_gfocal_loss.py

@@ -0,0 +1,34 @@
+import pytest
+import torch
+
+from nanodet.model.loss.gfocal_loss import DistributionFocalLoss, QualityFocalLoss
+
+
+def test_qfl():
+    with pytest.raises(AssertionError):
+        QualityFocalLoss(use_sigmoid=False)
+
+    label = torch.randint(low=0, high=7, size=(10,))
+    score = torch.rand((10,))
+    pred = torch.rand((10, 7))
+    target = (label, score)
+    weight = torch.zeros(10)
+
+    loss = QualityFocalLoss()(pred, target, weight)
+    assert loss == 0.0
+
+    loss = QualityFocalLoss()(pred, target, weight, reduction_override="sum")
+    assert loss == 0.0
+
+
+def test_dfl():
+
+    pred = torch.rand((10, 7))
+    target = torch.rand((10,))
+    weight = torch.zeros(10)
+
+    loss = DistributionFocalLoss()(pred, target, weight)
+    assert loss == 0.0
+
+    loss = DistributionFocalLoss()(pred, target, weight, reduction_override="sum")
+    assert loss == 0.0