Modularized common checks, added tests to cover change in functionality

Fixed test_arange and added test_arange_mixed_dtype

The test_arange test was specifying out of bounds starting value
for certain types.

Added tests to based on examples highlighting discrepancies.

dpt.arange(-2.5, stop=200, step=100, dtype='int32') now produces
the sequence consistent with np.arange output.

So does dpt.arange(9.7, stop=200, step=100, dtype='i4')

```ipython
In [1]: import dpctl, dpctl.tensor as dpt, numpy as np

In [2]: dpt.asnumpy(dpt.arange(9.7, stop=200, step=100, dtype='i4'))
Out[2]: array([  9, 109], dtype=int32)

In [3]: np.arange(9.7, stop=200, step=100, dtype='i4')
Out[3]: array([  9, 109], dtype=int32)
```

```
ty = np.float32
assert (
   dpt.arange(
       ty(0), stop=ty(504.0), step=ty(100), dtype=ty
   ).shape == (5,)
)
```

```
In [4]: import numpy as np

In [5]: np.arange(-5, stop=10**5, step=2.7, dtype=np.int64).shape
Out[5]: (37039,)

In [6]: import dpctl.tensor as dpt

In [7]: dpt.arange(-5, stop=10**5, step=2.7, dtype=np.int64).shape
Out[7]: (50003,)
```

Author: oleksandr-pavlyk

dpctl/tests/helper/__init__.py

@@ -19,14 +19,18 @@
 
 from ._helper import (
     create_invalid_capsule,
+    get_queue_or_skip,
     has_cpu,
     has_gpu,
     has_sycl_platforms,
+    skip_if_dtype_not_supported,
 )
 
 __all__ = [
     "create_invalid_capsule",
     "has_cpu",
     "has_gpu",
     "has_sycl_platforms",
+    "get_queue_or_skip",
+    "skip_if_dtype_not_supported",
 ]

dpctl/tests/helper/_helper.py

@@ -14,6 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+
 import dpctl
 
 
@@ -39,3 +41,38 @@ def create_invalid_capsule():
     ctor.restype = ctypes.py_object
     ctor.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_void_p]
     return ctor(id(ctor), b"invalid", 0)
+
+
+def get_queue_or_skip(args=tuple()):
+    try:
+        q = dpctl.SyclQueue(*args)
+    except dpctl.SyclQueueCreationError:
+        pytest.skip(f"Queue could not be created from {args}")
+    return q
+
+
+def skip_if_dtype_not_supported(dt, q_or_dev):
+    import dpctl.tensor as dpt
+
+    dt = dpt.dtype(dt)
+    if type(q_or_dev) is dpctl.SyclQueue:
+        dev = q_or_dev.sycl_device
+    elif type(q_or_dev) is dpctl.SyclDevice:
+        dev = q_or_dev
+    else:
+        raise TypeError(
+            "Expected dpctl.SyclQueue or dpctl.SyclDevice, "
+            f"got {type(q_or_dev)}"
+        )
+    dev_has_dp = dev.has_aspect_fp64
+    if dev_has_dp is False and dt in [dpt.float64, dpt.complex128]:
+        pytest.skip(
+            f"{dev.name} does not support double precision floating point types"
+        )
+    dev_has_hp = dev.has_aspect_fp16
+    if dev_has_hp is False and dt in [
+        dpt.float16,
+    ]:
+        pytest.skip(
+            f"{dev.name} does not support half precision floating point type"
+        )