Added unit tests for the pad function and fixed pad function return v… (#22)

* Added unit tests for the pad function and fixed pad function return value

* fixed import formatting, black and flake8 automatic checks

---------

Co-authored-by: Chaluvadi <[email protected]>

Author: sakchal

arrayfire_wrapper/lib/create_and_modify_array/create_array/pad.py

@@ -22,4 +22,4 @@ def pad(arr: AFArray, begin_shape: tuple[int, ...], end_shape: tuple[int, ...],
         end_c_shape.c_array,
         border_type.value,
     )
-    return NotImplemented
+    return out

tests/test_pad.py

@@ -0,0 +1,71 @@
+import random
+
+import numpy as np
+import pytest
+
+import arrayfire_wrapper.dtypes as dtypes
+import arrayfire_wrapper.lib as wrapper
+
+
+@pytest.mark.parametrize(
+    "original_shape",
+    [
+        (random.randint(1, 100),),
+        (random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+    ],
+)
+def test_zero_padding(original_shape: tuple) -> None:
+    """Test if pad creates an array with no padding if no padding is given"""
+    original_array = wrapper.constant(2, original_shape, dtypes.s64)
+    padding = wrapper.Pad(0)
+
+    zero_shape = tuple(0 for _ in range(len(original_shape)))
+    result = wrapper.pad(original_array, zero_shape, zero_shape, padding)
+
+    assert wrapper.get_dims(result)[0 : len(original_shape)] == original_shape  # noqa: E203
+
+
+@pytest.mark.parametrize(
+    "original_shape",
+    [
+        (random.randint(1, 100),),
+        (random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+    ],
+)
+def test_negative_padding(original_shape: tuple) -> None:
+    """Test if pad can properly handle if negative padding is given"""
+    with pytest.raises(RuntimeError):
+        original_array = wrapper.constant(2, original_shape, dtypes.s64)
+        padding = wrapper.Pad(0)
+
+        neg_shape = tuple(-1 for _ in range(len(original_shape)))
+        result = wrapper.pad(original_array, neg_shape, neg_shape, padding)
+
+        assert wrapper.get_dims(result)[0 : len(original_shape)] == original_shape  # noqa: E203
+
+
+@pytest.mark.parametrize(
+    "original_shape",
+    [
+        (random.randint(1, 100),),
+        (random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+        (random.randint(1, 100), random.randint(1, 100), random.randint(1, 100), random.randint(1, 100)),
+    ],
+)
+def test_padding_shape(original_shape: tuple) -> None:
+    """Test if pad outputs the correct shape when a padding is adding to the original array"""
+    original_array = wrapper.constant(2, original_shape, dtypes.s64)
+    padding = wrapper.Pad(0)
+
+    beg_shape = tuple(random.randint(1, 10) for _ in range(len(original_shape)))
+    end_shape = tuple(random.randint(1, 10) for _ in range(len(original_shape)))
+
+    result = wrapper.pad(original_array, beg_shape, end_shape, padding)
+    new_shape = np.array(beg_shape) + np.array(end_shape) + np.array(original_shape)
+
+    assert wrapper.get_dims(result)[0 : len(original_shape)] == tuple(new_shape)  # noqa: E203