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OBLITERATUS/tests/test_metrics.py
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Python

"""Tests for evaluation metrics."""
from __future__ import annotations
import pytest
import torch
from obliteratus.evaluation.metrics import accuracy, f1_score_metric, perplexity
class TestPerplexity:
def test_perfect_prediction(self):
# Create logits that strongly predict the correct next token
vocab_size = 10
seq_len = 5
batch_size = 1
labels = torch.tensor([[0, 1, 2, 3, 4]])
logits = torch.full((batch_size, seq_len, vocab_size), -100.0)
# Set high logit for the correct next token
for t in range(seq_len - 1):
logits[0, t, labels[0, t + 1]] = 100.0
ppl = perplexity(logits, labels)
assert ppl < 2.0, f"Expected near-1 perplexity, got {ppl}"
def test_random_prediction_higher(self):
vocab_size = 100
seq_len = 20
batch_size = 2
torch.manual_seed(42)
logits = torch.randn(batch_size, seq_len, vocab_size)
labels = torch.randint(0, vocab_size, (batch_size, seq_len))
ppl = perplexity(logits, labels)
assert ppl > 10, f"Random logits should yield high perplexity, got {ppl}"
def test_uniform_logits_equal_vocabulary_size(self):
logits = torch.zeros(2, 4, 7)
labels = torch.tensor([[0, 1, 2, 3], [3, 4, 5, 6]])
assert perplexity(logits, labels) == pytest.approx(7.0)
@pytest.mark.parametrize(
("logits", "labels", "message"),
[
(torch.zeros(2, 3), torch.zeros(2, 3, dtype=torch.long), "3D"),
(torch.zeros(2, 3, 4), torch.zeros(2, 3, 1, dtype=torch.long), "2D"),
(torch.zeros(2, 3, 4), torch.zeros(2, 2, dtype=torch.long), "does not match"),
(torch.zeros(2, 1, 4), torch.zeros(2, 1, dtype=torch.long), "two sequence"),
],
)
def test_rejects_invalid_shapes(self, logits, labels, message):
with pytest.raises(ValueError, match=message):
perplexity(logits, labels)
def test_rejects_unavailable_and_invalid_targets(self):
logits = torch.zeros(1, 3, 4)
with pytest.raises(ValueError, match="every target"):
perplexity(logits, torch.full((1, 3), -100))
with pytest.raises(ValueError, match="outside"):
perplexity(logits, torch.tensor([[0, 1, 9]]))
logits[0, 0, 0] = float("nan")
with pytest.raises(ValueError, match="finite"):
perplexity(logits, torch.tensor([[0, 1, 2]]))
def test_rejects_non_integer_labels(self):
with pytest.raises(ValueError, match="integer token IDs"):
perplexity(torch.zeros(1, 3, 4), torch.zeros(1, 3))
class TestAccuracy:
def test_perfect(self):
assert accuracy([1, 2, 3], [1, 2, 3]) == 1.0
def test_zero(self):
assert accuracy([1, 2, 3], [4, 5, 6]) == 0.0
def test_partial(self):
assert accuracy([1, 2, 3, 4], [1, 2, 0, 0]) == 0.5
def test_empty(self):
assert accuracy([], []) == 0.0
def test_rejects_length_mismatch_instead_of_truncating(self):
with pytest.raises(ValueError, match="equal length"):
accuracy([1, 2], [1])
class TestF1:
def test_perfect(self):
assert f1_score_metric([0, 1, 0, 1], [0, 1, 0, 1]) == 1.0
def test_zero(self):
score = f1_score_metric([0, 0, 0, 0], [1, 1, 1, 1])
assert score == 0.0
def test_empty(self):
assert f1_score_metric([], []) == 0.0
def test_rejects_length_mismatch(self):
with pytest.raises(ValueError, match="equal length"):
f1_score_metric([1, 2], [1])