fastembed/tests/test_sparse_embeddings.py

import os

import pytest
import numpy as np

from fastembed.sparse.bm25 import Bm25
from fastembed.sparse.sparse_text_embedding import SparseTextEmbedding
from tests.utils import delete_model_cache

CANONICAL_COLUMN_VALUES = {
    "prithvida/Splade_PP_en_v1": {
        "indices": [
            2040,
            2047,
            2088,
            2299,
            2748,
            3011,
            3376,
            3795,
            4774,
            5304,
            5798,
            6160,
            7592,
            7632,
            8484,
        ],
        "values": [
            0.4219532012939453,
            0.4320072531700134,
            2.766580104827881,
            0.3314574658870697,
            1.395172119140625,
            0.021595917642116547,
            0.43770670890808105,
            0.0008370947907678783,
            0.5187209844589233,
            0.17124654352664948,
            0.14742016792297363,
            0.8142819404602051,
            2.803262710571289,
            2.1904349327087402,
            1.0531445741653442,
        ],
    }
}

docs = ["Hello World"]


def test_batch_embedding() -> None:
    is_ci = os.getenv("CI")
    docs_to_embed = docs * 10

    for model_name, expected_result in CANONICAL_COLUMN_VALUES.items():
        model = SparseTextEmbedding(model_name=model_name)
        result = next(iter(model.embed(docs_to_embed, batch_size=6)))
        assert result.indices.tolist() == expected_result["indices"]

        for i, value in enumerate(result.values):
            assert pytest.approx(value, abs=0.001) == expected_result["values"][i]
        if is_ci:
            delete_model_cache(model.model._model_dir)


def test_single_embedding() -> None:
    is_ci = os.getenv("CI")
    for model_name, expected_result in CANONICAL_COLUMN_VALUES.items():
        model = SparseTextEmbedding(model_name=model_name)

        passage_result = next(iter(model.embed(docs, batch_size=6)))
        query_result = next(iter(model.query_embed(docs)))
        for result in [passage_result, query_result]:
            assert result.indices.tolist() == expected_result["indices"]

            for i, value in enumerate(result.values):
                assert pytest.approx(value, abs=0.001) == expected_result["values"][i]
        if is_ci:
            delete_model_cache(model.model._model_dir)


def test_parallel_processing() -> None:
    is_ci = os.getenv("CI")
    model = SparseTextEmbedding(model_name="prithivida/Splade_PP_en_v1")
    docs = ["hello world", "flag embedding"] * 30
    sparse_embeddings_duo = list(model.embed(docs, batch_size=10, parallel=2))
    sparse_embeddings_all = list(model.embed(docs, batch_size=10, parallel=0))
    sparse_embeddings = list(model.embed(docs, batch_size=10, parallel=None))

    assert (
        len(sparse_embeddings)
        == len(sparse_embeddings_duo)
        == len(sparse_embeddings_all)
        == len(docs)
    )

    for sparse_embedding, sparse_embedding_duo, sparse_embedding_all in zip(
        sparse_embeddings, sparse_embeddings_duo, sparse_embeddings_all
    ):
        assert (
            sparse_embedding.indices.tolist()
            == sparse_embedding_duo.indices.tolist()
            == sparse_embedding_all.indices.tolist()
        )
        assert np.allclose(sparse_embedding.values, sparse_embedding_duo.values, atol=1e-3)
        assert np.allclose(sparse_embedding.values, sparse_embedding_all.values, atol=1e-3)

    if is_ci:
        delete_model_cache(model.model._model_dir)


@pytest.fixture
def bm25_instance() -> None:
    ci = os.getenv("CI", True)
    model = Bm25("Qdrant/bm25", language="english")
    yield model
    if ci:
        delete_model_cache(model._model_dir)


def test_stem_with_stopwords_and_punctuation(bm25_instance: Bm25) -> None:
    # Setup
    bm25_instance.stopwords = {"the", "is", "a"}
    bm25_instance.punctuation = {".", ",", "!"}

    # Test data
    tokens = ["The", "quick", "brown", "fox", "is", "a", "test", "sentence", ".", "!"]

    # Execute
    result = bm25_instance._stem(tokens)

    # Assert
    expected = ["quick", "brown", "fox", "test", "sentenc"]
    assert result == expected, f"Expected {expected}, but got {result}"


def test_stem_case_insensitive_stopwords(bm25_instance: Bm25) -> None:
    # Setup
    bm25_instance.stopwords = {"the", "is", "a"}
    bm25_instance.punctuation = {".", ",", "!"}

    # Test data
    tokens = ["THE", "Quick", "Brown", "Fox", "IS", "A", "Test", "Sentence", ".", "!"]

    # Execute
    result = bm25_instance._stem(tokens)

    # Assert
    expected = ["quick", "brown", "fox", "test", "sentenc"]
    assert result == expected, f"Expected {expected}, but got {result}"


@pytest.mark.parametrize("disable_stemmer", [True, False])
def test_disable_stemmer_behavior(disable_stemmer: bool) -> None:
    # Setup
    model = Bm25("Qdrant/bm25", language="english", disable_stemmer=disable_stemmer)
    model.stopwords = {"the", "is", "a"}
    model.punctuation = {".", ",", "!"}

    # Test data
    tokens = ["The", "quick", "brown", "fox", "is", "a", "test", "sentence", ".", "!"]

    # Execute
    result = model._stem(tokens)

    # Assert
    if disable_stemmer:
        expected = ["quick", "brown", "fox", "test", "sentence"]  # no stemming, lower case only
    else:
        expected = ["quick", "brown", "fox", "test", "sentenc"]
    assert result == expected, f"Expected {expected}, but got {result}"


@pytest.mark.parametrize(
    "model_name",
    ["prithivida/Splade_PP_en_v1"],
)
def test_lazy_load(model_name: str) -> None:
    is_ci = os.getenv("CI")
    model = SparseTextEmbedding(model_name=model_name, lazy_load=True)
    assert not hasattr(model.model, "model")

    docs = ["hello world", "flag embedding"]
    list(model.embed(docs))
    assert hasattr(model.model, "model")

    model = SparseTextEmbedding(model_name=model_name, lazy_load=True)
    list(model.query_embed(docs))

    model = SparseTextEmbedding(model_name=model_name, lazy_load=True)
    list(model.passage_embed(docs))

    if is_ci:
        delete_model_cache(model.model._model_dir)