Xxhash test cleanup (#200)

* clean up of the rounding functions

* fix: time span math

* fix: type annotations

* cleanup xxhash tests

tests/xxhash/_xxhash_fixtures.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+from pathlib import Path
+from typing import TypedDict
+
+import ry
+
+_PWD = Path(__file__).parent.absolute()
+_TEST_DATA = _PWD / "xxhash.ndjson"
+
+XX32_SEEDS = [0, 1, 2**32 - 1]
+XX64_SEEDS = [0, 1, 2**64 - 1]
+XX128_SEEDS = [0, 1, 2**64 - 1]  # same as 64-bit seeds
+
+
+class XXHashDataRecord(TypedDict):
+    buf: str
+    xxh32_0x00000000: str
+    xxh32_0x00000001: str
+    xxh32_0xFFFFFFFF: str
+    xxh64_0x00000000: str
+    xxh64_0x00000001: str
+    xxh64_0xFFFFFFFFFFFFFFFF: str
+    xxh3_64_0x00000000: str
+    xxh3_64_0x00000001: str
+    xxh3_64_0xFFFFFFFFFFFFFFFF: str
+    xxh3_128_0x00000000: str
+    xxh3_128_0x00000001: str
+    xxh3_128_0xFFFFFFFFFFFFFFFF: str
+
+
+def _load_data():
+    with open(_TEST_DATA, "r") as f:
+        xx32_test_data = f.read()
+    lines = xx32_test_data.split("\n")
+    return [
+        XXHashDataRecord(
+            **row,
+        )
+        for row in (
+            ry.parse_json(line) for line in lines if line.strip() if line.strip()
+        )
+    ]
+
+
+XXHASH_TEST_DATA = _load_data()