Test gaussian alias (#287)

* Test `gaussian` alias

Currently the `gaussian` function shows up as not covered by testing.
This provides some test coverage of it.

* Test `gaussian` with CuPy

Include a CuPy test of `gaussian` as well.

* Include `gaussian` in `ndfilters`' `import`s

dask_image/ndfilters/__init__.py

@@ -6,6 +6,7 @@
     "laplace",
     "prewitt",
     "sobel",
+    "gaussian",
     "gaussian_filter",
     "gaussian_gradient_magnitude",
     "gaussian_laplace",
@@ -22,8 +23,8 @@
 from ._conv import convolve, correlate
 from ._diff import laplace
 from ._edge import prewitt, sobel
-from ._gaussian import (gaussian_filter, gaussian_gradient_magnitude,
-                        gaussian_laplace)
+from ._gaussian import (gaussian, gaussian_filter,
+                        gaussian_gradient_magnitude, gaussian_laplace)
 from ._generic import generic_filter
 from ._order import (maximum_filter, median_filter, minimum_filter,
                      percentile_filter, rank_filter)
@@ -38,6 +39,7 @@
 prewitt.__module__ = __name__
 sobel.__module__ = __name__
 
+gaussian.__module__ = __name__
 gaussian_filter.__module__ = __name__
 gaussian_gradient_magnitude.__module__ = __name__
 gaussian_laplace.__module__ = __name__

tests/test_dask_image/test_ndfilters/test__gaussian.py

@@ -21,6 +21,7 @@
 @pytest.mark.parametrize(
     "da_func",
     [
+        dask_image.ndfilters.gaussian,
         dask_image.ndfilters.gaussian_filter,
         dask_image.ndfilters.gaussian_gradient_magnitude,
         dask_image.ndfilters.gaussian_laplace,
@@ -48,7 +49,10 @@ def test_gaussian_filters_params(da_func, err_type, sigma, truncate):
 )
 @pytest.mark.parametrize(
     "sp_func, da_func",
-    [(scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian_filter)]
+    [
+        (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian),
+        (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian_filter),
+    ]
 )
 def test_gaussian_filters_identity(sp_func, da_func, order, sigma, truncate):
     a = np.arange(140.0).reshape(10, 14)
@@ -74,6 +78,7 @@ def test_gaussian_filters_identity(sp_func, da_func, order, sigma, truncate):
 @pytest.mark.parametrize(
     "da_func",
     [
+        dask_image.ndfilters.gaussian,
         dask_image.ndfilters.gaussian_filter,
         dask_image.ndfilters.gaussian_gradient_magnitude,
         dask_image.ndfilters.gaussian_laplace,
@@ -96,6 +101,7 @@ def test_gaussian_filter_shape_type(da_func):
 @pytest.mark.parametrize(
     "da_func",
     [
+        dask_image.ndfilters.gaussian,
         dask_image.ndfilters.gaussian_filter,
         dask_image.ndfilters.gaussian_gradient_magnitude,
         dask_image.ndfilters.gaussian_laplace,
@@ -129,6 +135,7 @@ def test_gaussian_filter_comprehensions(da_func):
 @pytest.mark.parametrize(
     "sp_func, da_func",
     [
+        (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian),
         (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian_filter),
         (scipy.ndimage.gaussian_gradient_magnitude,
          dask_image.ndfilters.gaussian_gradient_magnitude),
@@ -172,7 +179,10 @@ def test_gaussian_filters_compare(sp_func, da_func, sigma, truncate):
 )
 @pytest.mark.parametrize(
     "sp_func, da_func",
-    [(scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian_filter)]
+    [
+        (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian),
+        (scipy.ndimage.gaussian_filter, dask_image.ndfilters.gaussian_filter),
+    ]
 )
 def test_gaussian_derivative_filters_compare(sp_func, da_func,
                                              order, sigma, truncate):

tests/test_dask_image/test_ndfilters/test_cupy_ndfilters.py

@@ -51,6 +51,7 @@ def test_cupy_edge(array, func):
 
 @pytest.mark.cupy
 @pytest.mark.parametrize("func", [
+    dask_image.ndfilters.gaussian,
     dask_image.ndfilters.gaussian_filter,
     dask_image.ndfilters.gaussian_gradient_magnitude,
     dask_image.ndfilters.gaussian_laplace,