FIX: incorrect regex for matching float string

    * add tests for `save_int` and `save_float` in `fastf1.ergast.structure`

fastf1/ergast/structure.py

@@ -99,7 +99,7 @@ def save_int(i_str) -> int:
     """
     # Match pure integer strings, e.g.
     #   - '1234' -> 1234
-    if re.match(r'^-?\d+$', i_str):
+    if re.match(r'^[+-]?\d+$', i_str):
         return int(i_str)
 
     # Otherwise, return -1. A notable example is #432: 1954 British GP, where
@@ -115,7 +115,7 @@ def save_float(f_str) -> float:
     """
     # Match pure float strings, e.g.
     #   - '1234.5678' -> 1234.5678
-    if re.match(r'^-?\d*\.?\d*$', f_str):
+    if re.match(r'^[+-]?([0-9]+([.][0-9]*)?|[.][0-9]+)$', f_str):
         return float(f_str)
 
     # Otherwise, return np.nan

fastf1/tests/test_ergast.py

@@ -16,7 +16,9 @@
 from fastf1.ergast.structure import \
     date_from_ergast, \
     time_from_ergast, \
-    timedelta_from_ergast
+    timedelta_from_ergast, \
+    save_int, \
+    save_float
 
 
 # ############### test structure.py #################################
@@ -176,6 +178,31 @@ def test_timedelta_from_ergast_error(time_string, caplog):
     assert "Failed to parse" in caplog.text
 
 
+@pytest.mark.parametrize(
+    "int_string, expected",
+    (
+        ("123", 123),
+        ("-4", -4),
+        ("", -1),
+        ("123.0", -1)
+    )
+)
+def test_save_int(int_string, expected):
+    assert save_int(int_string) == expected
+
+
+@pytest.mark.parametrize(
+    "float_string, expected",
+    (
+        ("123.4", 123.4),
+        ("-5.6", -5.6),
+        ("", float('nan'))
+    )
+)
+def test_save_float(float_string, expected):
+    assert save_float(float_string) == pytest.approx(expected, nan_ok=True)
+
+
 @pytest.mark.parametrize(
     "data, cast, rename, expected",
     (