Fix cunumeric.arange issues (#940)

* Infer arange dtype from input arguments

* Fix arange error when ceil((stop - start)/step) is a negative number

* Remove invalid test and add the params to basic test.

cunumeric/module.py

@@ -663,12 +663,12 @@ def arange(
         step = 1
 
     if dtype is None:
-        dtype = np.array([stop]).dtype
+        dtype = np.find_common_type([], [type(start), type(stop), type(step)])
     else:
         dtype = np.dtype(dtype)
 
     N = math.ceil((stop - start) / step)
-    result = ndarray((N,), dtype)
+    result = ndarray((_builtin_max(0, N),), dtype)
     result._thunk.arange(start, stop, step)
     return result
 

tests/integration/test_array_creation.py

@@ -191,11 +191,12 @@ def test_full_like_bad_filled_value():
     (0,),
     (10,),
     (3.5,),
-    pytest.param((-10), marks=pytest.mark.xfail),
+    (3.0, 8, None),
+    (-10,),
     (2, 10),
-    pytest.param((2, -10), marks=pytest.mark.xfail),
+    (2, -10),
     (-2.5, 10.0),
-    pytest.param((1, -10, -2.5), marks=pytest.mark.xfail),
+    (1, -10, -2.5),
     (1.0, -10.0, -2.5),
     (-10, 10, 10),
     (-10, 10, -100),

tests/integration/test_diag_indices.py

@@ -20,9 +20,10 @@
 import cunumeric as num
 
 
-def test_diag_indices_default_ndim():
-    a_np = np.diag_indices(10)
-    a_num = num.diag_indices(10)
+@pytest.mark.parametrize("n", [10, -10.5, -1])
+def test_diag_indices_default_ndim(n):
+    a_np = np.diag_indices(n)
+    a_num = num.diag_indices(n)
     assert np.array_equal(a_np, a_num)
 
 
@@ -42,11 +43,6 @@ def test_diag_indices(n, ndim):
 
 
 class TestDiagIndicesErrors:
-    @pytest.mark.parametrize("n", [-10.5, -1])
-    def test_negative_n(self, n):
-        with pytest.raises(ValueError):
-            num.diag_indices(n)
-
     @pytest.mark.xfail
     @pytest.mark.parametrize("n", [-10.5, -1])
     def test_negative_n_DIVERGENCE(self, n):