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Testing Knowledge Graph Index Implementation in llama_index

This test suite validates the KnowledgeGraphIndex implementation in llama_index, focusing on graph construction, triplet extraction, and embedding functionality. It ensures proper handling of knowledge graph operations and data relationships.

Test Coverage Overview

The test suite provides comprehensive coverage of KnowledgeGraphIndex functionality including:
  • Manual knowledge graph construction and triplet insertion
  • Similarity-based graph building with embeddings
  • Document-based graph construction
  • Triplet response parsing and validation
Key edge cases tested include duplicate node insertion and various triplet formats.

Implementation Analysis

The testing approach uses pytest fixtures and mocking to isolate components:
  • MockEmbedding class for controlled embedding generation
  • Patched triplet extraction for predictable behavior
  • Structured test cases validating graph construction and querying
The implementation leverages pytest’s powerful mocking capabilities and fixture management.

Technical Details

Testing tools and configuration:
  • pytest for test framework
  • unittest.mock for component isolation
  • Custom fixtures for test data setup
  • Mock embeddings with controlled dimensionality
  • Patched extraction methods for deterministic behavior

Best Practices Demonstrated

The test suite exemplifies several testing best practices:
  • Isolated unit tests with proper mocking
  • Comprehensive edge case coverage
  • Clear test structure and organization
  • Effective use of fixtures for test data
  • Validation of both success and error paths

run-llama/llama_index

llama-index-core/tests/indices/knowledge_graph/test_base.py

            
"""Test knowledge graph index."""

from typing import Any, Dict, List, Tuple
from unittest.mock import patch

import pytest
from llama_index.core.base.embeddings.base import BaseEmbedding
from llama_index.core.indices.knowledge_graph.base import KnowledgeGraphIndex
from llama_index.core.schema import Document, TextNode
from tests.mock_utils.mock_prompts import (
    MOCK_KG_TRIPLET_EXTRACT_PROMPT,
    MOCK_QUERY_KEYWORD_EXTRACT_PROMPT,
)


class MockEmbedding(BaseEmbedding):
    @classmethod
    def class_name(cls) -> str:
        return "MockEmbedding"

    async def _aget_query_embedding(self, query: str) -> List[float]:
        del query
        return [0, 0, 1, 0, 0]

    async def _aget_text_embedding(self, text: str) -> List[float]:
        # assume dimensions are 4
        if text == "('foo', 'is', 'bar')":
            return [1, 0, 0, 0]
        elif text == "('hello', 'is not', 'world')":
            return [0, 1, 0, 0]
        elif text == "('Jane', 'is mother of', 'Bob')":
            return [0, 0, 1, 0]
        elif text == "foo":
            return [0, 0, 0, 1]
        else:
            raise ValueError("Invalid text for `mock_get_text_embedding`.")

    def _get_text_embedding(self, text: str) -> List[float]:
        """Mock get text embedding."""
        # assume dimensions are 4
        if text == "('foo', 'is', 'bar')":
            return [1, 0, 0, 0]
        elif text == "('hello', 'is not', 'world')":
            return [0, 1, 0, 0]
        elif text == "('Jane', 'is mother of', 'Bob')":
            return [0, 0, 1, 0]
        elif text == "foo":
            return [0, 0, 0, 1]
        else:
            raise ValueError("Invalid text for `mock_get_text_embedding`.")

    def _get_query_embedding(self, query: str) -> List[float]:
        """Mock get query embedding."""
        del query
        return [0, 0, 1, 0, 0]


@pytest.fixture()
def struct_kwargs() -> Tuple[Dict, Dict]:
    """Index kwargs."""
    index_kwargs = {
        "kg_triplet_extract_template": MOCK_KG_TRIPLET_EXTRACT_PROMPT,
    }
    query_kwargs = {
        "query_keyword_extract_template": MOCK_QUERY_KEYWORD_EXTRACT_PROMPT,
    }
    return index_kwargs, query_kwargs


def mock_extract_triplets(text: str) -> List[Tuple[str, str, str]]:
    """Mock extract triplets."""
    lines = text.split("
")
    triplets: List[Tuple[str, str, str]] = []
    for line in lines:
        tokens = line[1:-1].split(",")
        tokens = [t.strip() for t in tokens]

        subj, pred, obj = tokens
        triplets.append((subj, pred, obj))
    return triplets


@patch.object(
    KnowledgeGraphIndex, "_extract_triplets", side_effect=mock_extract_triplets
)
def test_build_kg_manual(_patch_extract_triplets: Any) -> None:
    """Test build knowledge graph."""
    index = KnowledgeGraphIndex([])
    tuples = [
        ("foo", "is", "bar"),
        ("hello", "is not", "world"),
        ("Jane", "is mother of", "Bob"),
    ]
    nodes = [TextNode(text=str(tup)) for tup in tuples]
    for tup, node in zip(tuples, nodes):
        # add node
        index.add_node([tup[0], tup[2]], node)
        # add triplet
        index.upsert_triplet(tup)

    # NOTE: in these unit tests, document text == triplets
    docstore_nodes = index.docstore.get_nodes(list(index.index_struct.node_ids))
    table_chunks = {n.get_content() for n in docstore_nodes}
    assert len(table_chunks) == 3
    assert "('foo', 'is', 'bar')" in table_chunks
    assert "('hello', 'is not', 'world')" in table_chunks
    assert "('Jane', 'is mother of', 'Bob')" in table_chunks

    # test that expected keys are present in table
    # NOTE: in mock keyword extractor, stopwords are not filtered
    assert index.index_struct.table.keys() == {
        "foo",
        "bar",
        "hello",
        "world",
        "Jane",
        "Bob",
    }

    # test upsert_triplet_and_node
    index = KnowledgeGraphIndex([])
    tuples = [
        ("foo", "is", "bar"),
        ("hello", "is not", "world"),
        ("Jane", "is mother of", "Bob"),
    ]
    nodes = [TextNode(text=str(tup)) for tup in tuples]
    for tup, node in zip(tuples, nodes):
        index.upsert_triplet_and_node(tup, node)

    # NOTE: in these unit tests, document text == triplets
    docstore_nodes = index.docstore.get_nodes(list(index.index_struct.node_ids))
    table_chunks = {n.get_content() for n in docstore_nodes}
    assert len(table_chunks) == 3
    assert "('foo', 'is', 'bar')" in table_chunks
    assert "('hello', 'is not', 'world')" in table_chunks
    assert "('Jane', 'is mother of', 'Bob')" in table_chunks

    # test that expected keys are present in table
    # NOTE: in mock keyword extractor, stopwords are not filtered
    assert index.index_struct.table.keys() == {
        "foo",
        "bar",
        "hello",
        "world",
        "Jane",
        "Bob",
    }

    # try inserting same node twice
    index = KnowledgeGraphIndex([])
    node = TextNode(text=str(("foo", "is", "bar")), id_="test_node")
    index.upsert_triplet_and_node(tup, node)
    index.upsert_triplet_and_node(tup, node)


@patch.object(
    KnowledgeGraphIndex, "_extract_triplets", side_effect=mock_extract_triplets
)
def test_build_kg_similarity(
    _patch_extract_triplets: Any, documents: List[Document]
) -> None:
    """Test build knowledge graph."""
    index = KnowledgeGraphIndex.from_documents(
        documents, include_embeddings=True, embed_model=MockEmbedding()
    )
    # get embedding dict from KG index struct
    rel_text_embeddings = index.index_struct.embedding_dict

    # check that all rel_texts were embedded
    assert len(rel_text_embeddings) == 3
    for rel_text, embedding in rel_text_embeddings.items():
        assert embedding == MockEmbedding().get_text_embedding(rel_text)


@patch.object(
    KnowledgeGraphIndex, "_extract_triplets", side_effect=mock_extract_triplets
)
def test_build_kg(
    _patch_extract_triplets: Any, documents: List[Document], patch_token_text_splitter
) -> None:
    """Test build knowledge graph."""
    index = KnowledgeGraphIndex.from_documents(documents)
    # NOTE: in these unit tests, document text == triplets
    nodes = index.docstore.get_nodes(list(index.index_struct.node_ids))
    table_chunks = {n.get_content() for n in nodes}
    assert len(table_chunks) == 3
    assert "(foo, is, bar)" in table_chunks
    assert "(hello, is not, world)" in table_chunks
    assert "(Jane, is mother of, Bob)" in table_chunks

    # test that expected keys are present in table
    # NOTE: in mock keyword extractor, stopwords are not filtered
    assert index.index_struct.table.keys() == {
        "foo",
        "bar",
        "hello",
        "world",
        "Jane",
        "Bob",
    }

    # test ref doc info for three nodes, single doc
    all_ref_doc_info = index.ref_doc_info
    assert len(all_ref_doc_info) == 1
    for ref_doc_info in all_ref_doc_info.values():
        assert len(ref_doc_info.node_ids) == 3


def test__parse_triplet_response(doc_triplets_with_text_around: List[Document]) -> None:
    """Test build knowledge graph with triplet response in other format."""
    parsed_triplets = []
    for doc_triplet in doc_triplets_with_text_around:
        parsed_triplets.append(
            KnowledgeGraphIndex._parse_triplet_response(doc_triplet.text)
        )
    assert len(parsed_triplets) == 1
    assert len(parsed_triplets[0]) == 3
    # Expecting Capitalized triplet Outputs
    assert ("Foo", "Is", "Bar") in parsed_triplets[0]
    assert ("Hello", "Is not", "World") in parsed_triplets[0]
    assert ("Jane", "Is mother of", "Bob") in parsed_triplets[0]