solving span bugs (#57)

tests/test_pinn.py

@@ -70,6 +70,32 @@ def test_span_pts():
     assert pinn.input_pts['D'].shape[0] == n
 
 
+def test_sampling_all_args():
+    pinn = PINN(problem, model)
+    n = 10
+    pinn.span_pts(n, 'grid', locations=['D'])
+
+
+def test_sampling_all_kwargs():
+    pinn = PINN(problem, model)
+    n = 10
+    pinn.span_pts(n=n, mode='latin', locations=['D'])
+
+
+def test_sampling_dict():
+    pinn = PINN(problem, model)
+    n = 10
+    pinn.span_pts(
+        {'variables': ['x', 'y'], 'mode': 'grid', 'n': n}, locations=['D'])
+
+
+def test_sampling_mixed_args_kwargs():
+    pinn = PINN(problem, model)
+    n = 10
+    with pytest.raises(ValueError):
+        pinn.span_pts(n, mode='latin', locations=['D'])
+
+
 def test_train():
     pinn = PINN(problem, model)
     boundaries = ['gamma1', 'gamma2', 'gamma3', 'gamma4']
@@ -130,4 +156,4 @@ if torch.cuda.is_available():
         n = 100
         pinn.span_pts(n, 'grid', boundaries)
         pinn.span_pts(n, 'grid', locations=['D'])
-        pinn.train(5)
+        pinn.train(5)