Enhance Array Flattening Utility with Robust Nested Array Handling

src/array_flattener.py

@@ -0,0 +1,35 @@
+from typing import List, Union
+
+def flatten_array(arr: List[Union[int, List]]) -> List[int]:
+    """
+    Recursively flatten a nested array of integers.
+
+    Args:
+        arr (List[Union[int, List]]): A potentially nested list of integers.
+
+    Returns:
+        List[int]: A flattened list containing all integers from the input.
+
+    Raises:
+        TypeError: If the input contains non-integer and non-list elements.
+
+    Examples:
+        >>> flatten_array([1, [2, 3], 4])
+        [1, 2, 3, 4]
+        >>> flatten_array([1, [2, [3, 4]], 5])
+        [1, 2, 3, 4, 5]
+    """
+    flattened = []
+
+    for item in arr:
+        # If the item is a list, recursively flatten it
+        if isinstance(item, list):
+            flattened.extend(flatten_array(item))
+        # If the item is an integer, add it to the result
+        elif isinstance(item, int):
+            flattened.append(item)
+        # Raise an error for any other type
+        else:
+            raise TypeError(f"Unsupported type in array: {type(item)}")
+
+    return flattened

tests/test_array_flattener.py

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+import pytest
+from src.array_flattener import flatten_array
+
+def test_flatten_simple_array():
+    """Test flattening a simple array."""
+    assert flatten_array([1, 2, 3]) == [1, 2, 3]
+
+def test_flatten_nested_array():
+    """Test flattening a nested array."""
+    assert flatten_array([1, [2, 3], 4]) == [1, 2, 3, 4]
+
+def test_flatten_deeply_nested_array():
+    """Test flattening a deeply nested array."""
+    assert flatten_array([1, [2, [3, 4]], 5]) == [1, 2, 3, 4, 5]
+
+def test_flatten_empty_array():
+    """Test flattening an empty array."""
+    assert flatten_array([]) == []
+
+def test_flatten_single_element_array():
+    """Test flattening an array with a single element."""
+    assert flatten_array([42]) == [42]
+
+def test_flatten_multiple_levels_of_nesting():
+    """Test flattening an array with multiple levels of nesting."""
+    assert flatten_array([1, [2, [3, [4, 5]]], 6]) == [1, 2, 3, 4, 5, 6]
+
+def test_unsupported_type_raises_error():
+    """Test that an error is raised for unsupported types."""
+    with pytest.raises(TypeError):
+        flatten_array([1, 2, "3"])
+
+    with pytest.raises(TypeError):
+        flatten_array([1, [2, 3.14], 4])
+
+def test_mixed_nesting_with_integers():
+    """Test flattening an array with mixed nesting."""
+    assert flatten_array([1, [], [2, 3], [[4]], 5]) == [1, 2, 3, 4, 5]