fix: Rounding issues in score_answer and add unit tests (#462)

tests/test_power_function.py

@@ -1,5 +1,7 @@
 """Tests for Power Function questions generation"""
 
+from decimal import Decimal
+
 import pytest
 
 from reasoning_gym.arithmetic import PowerFunctionConfig, PowerFunctionDataset
@@ -82,3 +84,46 @@ def test_power_function_curriculum():
 
     increased_cfg = curriculum.generate_configuration(base_value)
     assert increased_cfg.min_exponent == 2 and increased_cfg.max_exponent == 4
+
+
+# Test score_answer function with various answers
+def test_power_function_score_answer_for_edge_cases():
+    """Test score_answer function for edge cases"""
+    config = PowerFunctionConfig(seed=42)
+    dataset = PowerFunctionDataset(config)
+
+    # Case 1: Match with trailing zeros
+    item = dataset[0].copy()
+    user_answer = "1.000e+00"
+    # Let's change the oracle answer for edge case testing
+    item["answer"] = "1.0"
+    score = dataset.score_answer(user_answer, item)
+    assert score == 1.0, f"Expected score 1.0, got {score}"
+
+    # Case 2: Rounding up at edge of significant figures
+    item = dataset[0].copy()
+    item["answer"] = str(Decimal("0.9999") ** 1)  # Close to 1.000
+    user_answer = "1.00"
+    score = dataset.score_answer(user_answer, item)
+    assert score == 1.0, f"Expected score 1.0, got {score}"
+
+    # Case 3: Negative base, valid exponent
+    item = dataset[0].copy()
+    item["answer"] = str(Decimal("-2.00") ** 3)  # -8.0
+    user_answer = "-8.00"
+    score = dataset.score_answer(user_answer, item)
+    assert score == 1.0, f"Expected score 1.0, got {score}"
+
+    # Case 4: Very small number with exponent notation
+    item = dataset[0].copy()
+    item["answer"] = str(Decimal("1e-6"))  # 1e-6
+    user_answer = "1.00e-6"
+    score = dataset.score_answer(user_answer, item)
+    assert score == 1.0, f"Expected score 1.0, got {score}"
+
+    # Case 5: Incorrect answer should yield low score
+    item = dataset[0].copy()
+    item["answer"] = "1000.0"
+    user_answer = "999.0"
+    score = dataset.score_answer(user_answer, item)
+    assert score == 0.01, f"Expected low score 0.01, got {score}"