Add a basic test for convert_to_pattern

tests/test_patterns.py

@@ -1,9 +1,22 @@
+import pytest
 from hypothesis import given
 from hypothesis import strategies as st
 
-from search_offsets.patterns import hex_to_bytes
+from search_offsets.patterns import convert_to_pattern, hex_to_bytes
 
 
 @given(st.integers(0, 255))
 def test_hex_to_bytes(byte: int):
     assert hex_to_bytes(f"{byte:02X}") == byte.to_bytes(1, "little")
+
+
+@pytest.mark.parametrize(
+    ("pattern", "expected"),
+    [
+        (["??"], [None]),
+        (["FF"], [255]),
+        (["FF", "??"], [255, None]),
+    ],
+)
+def test_convert_to_pattern(pattern: str, expected: list[int | None]):
+    assert convert_to_pattern(pattern) == expected