Harrison/csv loader (#3771)

Co-authored-by: mrT23 <tal.r@codium.ai>

langchain/document_loaders/csv_loader.py

@@ -1,4 +1,4 @@
-from csv import DictReader
+import csv
 from typing import Dict, List, Optional
 
 from langchain.docstore.document import Document
@@ -38,23 +38,30 @@ class CSVLoader(BaseLoader):
         self.encoding = encoding
         if csv_args is None:
             self.csv_args = {
-                "delimiter": ",",
-                "quotechar": '"',
+                "delimiter": csv.Dialect.delimiter,
+                "quotechar": csv.Dialect.quotechar,
             }
         else:
             self.csv_args = csv_args
 
     def load(self) -> List[Document]:
-        docs = []
+        """Load data into document objects."""
 
+        docs = []
         with open(self.file_path, newline="", encoding=self.encoding) as csvfile:
-            csv = DictReader(csvfile, **self.csv_args)  # type: ignore
-            for i, row in enumerate(csv):
+            csv_reader = csv.DictReader(csvfile, **self.csv_args)  # type: ignore
+            for i, row in enumerate(csv_reader):
                 content = "\n".join(f"{k.strip()}: {v.strip()}" for k, v in row.items())
-                if self.source_column is not None:
-                    source = row[self.source_column]
-                else:
-                    source = self.file_path
+                try:
+                    source = (
+                        row[self.source_column]
+                        if self.source_column is not None
+                        else self.file_path
+                    )
+                except KeyError:
+                    raise ValueError(
+                        f"Source column '{self.source_column}' not found in CSV file."
+                    )
                 metadata = {"source": source, "row": i}
                 doc = Document(page_content=content, metadata=metadata)
                 docs.append(doc)

poetry.lock

@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.4.2 and should not be changed by hand.
+# This file is automatically @generated by Poetry and should not be changed by hand.
 
 [[package]]
 name = "absl-py"
@@ -6270,6 +6270,24 @@ files = [
 pytest = ">=5.0.0"
 python-dotenv = ">=0.9.1"
 
+[[package]]
+name = "pytest-mock"
+version = "3.10.0"
+description = "Thin-wrapper around the mock package for easier use with pytest"
+category = "dev"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "pytest-mock-3.10.0.tar.gz", hash = "sha256:fbbdb085ef7c252a326fd8cdcac0aa3b1333d8811f131bdcc701002e1be7ed4f"},
+    {file = "pytest_mock-3.10.0-py3-none-any.whl", hash = "sha256:f4c973eeae0282963eb293eb173ce91b091a79c1334455acfac9ddee8a1c784b"},
+]
+
+[package.dependencies]
+pytest = ">=5.0"
+
+[package.extras]
+dev = ["pre-commit", "pytest-asyncio", "tox"]
+
 [[package]]
 name = "pytest-vcr"
 version = "1.0.2"
@@ -7655,7 +7673,7 @@ files = [
 ]
 
 [package.dependencies]
-greenlet = {version = "!=0.4.17", markers = "python_version >= \"3\" and platform_machine == \"aarch64\" or python_version >= \"3\" and platform_machine == \"ppc64le\" or python_version >= \"3\" and platform_machine == \"x86_64\" or python_version >= \"3\" and platform_machine == \"amd64\" or python_version >= \"3\" and platform_machine == \"AMD64\" or python_version >= \"3\" and platform_machine == \"win32\" or python_version >= \"3\" and platform_machine == \"WIN32\""}
+greenlet = {version = "!=0.4.17", markers = "python_version >= \"3\" and (platform_machine == \"aarch64\" or platform_machine == \"ppc64le\" or platform_machine == \"x86_64\" or platform_machine == \"amd64\" or platform_machine == \"AMD64\" or platform_machine == \"win32\" or platform_machine == \"WIN32\")"}
 
 [package.extras]
 aiomysql = ["aiomysql", "greenlet (!=0.4.17)"]
@@ -9418,15 +9436,15 @@ cffi = {version = ">=1.11", markers = "platform_python_implementation == \"PyPy\
 cffi = ["cffi (>=1.11)"]
 
 [extras]
-all = ["aleph-alpha-client", "anthropic", "arxiv", "atlassian-python-api", "azure-cosmos", "azure-identity", "beautifulsoup4", "clickhouse-connect", "cohere", "deeplake", "duckduckgo-search", "elasticsearch", "faiss-cpu", "google-api-python-client", "google-search-results", "gptcache", "html2text", "huggingface_hub", "jina", "jinja2", "lancedb", "lark", "manifest-ml", "networkx", "nlpcloud", "nltk", "nomic", "openai", "opensearch-py", "pexpect", "pgvector", "pinecone-client", "pinecone-text", "psycopg2-binary", "pyowm", "pypdf", "pytesseract", "qdrant-client", "redis", "sentence-transformers", "spacy", "tensorflow-text", "tiktoken", "torch", "transformers", "weaviate-client", "wikipedia", "wolframalpha"]
-azure = ["azure-core", "azure-cosmos", "azure-identity", "openai"]
+all = ["anthropic", "cohere", "openai", "nlpcloud", "huggingface_hub", "jina", "manifest-ml", "elasticsearch", "opensearch-py", "google-search-results", "faiss-cpu", "sentence-transformers", "transformers", "spacy", "nltk", "wikipedia", "beautifulsoup4", "tiktoken", "torch", "jinja2", "pinecone-client", "pinecone-text", "weaviate-client", "redis", "google-api-python-client", "wolframalpha", "qdrant-client", "tensorflow-text", "pypdf", "networkx", "nomic", "aleph-alpha-client", "deeplake", "pgvector", "psycopg2-binary", "pyowm", "pytesseract", "html2text", "atlassian-python-api", "gptcache", "duckduckgo-search", "arxiv", "azure-identity", "clickhouse-connect", "azure-cosmos", "lancedb", "lark", "pexpect", "pyvespa"]
+azure = ["azure-identity", "azure-cosmos", "openai", "azure-core"]
 cohere = ["cohere"]
 embeddings = ["sentence-transformers"]
-llms = ["anthropic", "cohere", "huggingface_hub", "manifest-ml", "nlpcloud", "openai", "torch", "transformers"]
+llms = ["anthropic", "cohere", "openai", "nlpcloud", "huggingface_hub", "manifest-ml", "torch", "transformers"]
 openai = ["openai"]
 qdrant = ["qdrant-client"]
 
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.1,<4.0"
-content-hash = "2ef913e267f1a10beee9f97924dc38df89fbe8a1ddc0de0f6e6f04e272763823"
+content-hash = "bfd037a6e4fbe62305bc1305999cc0cc83d84a740ebf8f66036d9ae4d59a5760"

pyproject.toml

@@ -101,6 +101,7 @@ freezegun = "^1.2.2"
 responses = "^0.22.0"
 pytest-asyncio = "^0.20.3"
 lark = "^1.1.5"
+pytest-mock  = "^3.10.0"
 
 [tool.poetry.group.test_integration]
 optional = true

tests/unit_tests/document_loader/test_csv_loader.py

@@ -0,0 +1,106 @@
+from pytest_mock import MockerFixture
+
+from langchain.docstore.document import Document
+from langchain.document_loaders.csv_loader import CSVLoader
+
+
+class TestCSVLoader:
+    # Tests that a CSV file with valid data is loaded successfully.
+    def test_csv_loader_load_valid_data(self, mocker: MockerFixture) -> None:
+        # Setup
+        file_path = "test.csv"
+        expected_docs = [
+            Document(
+                page_content="column1: value1\ncolumn2: value2\ncolumn3: value3",
+                metadata={"source": file_path, "row": 0},
+            ),
+            Document(
+                page_content="column1: value4\ncolumn2: value5\ncolumn3: value6",
+                metadata={"source": file_path, "row": 1},
+            ),
+        ]
+        mocker.patch("builtins.open", mocker.mock_open())
+        mock_csv_reader = mocker.patch("csv.DictReader")
+        mock_csv_reader.return_value = [
+            {"column1": "value1", "column2": "value2", "column3": "value3"},
+            {"column1": "value4", "column2": "value5", "column3": "value6"},
+        ]
+
+        # Exercise
+        loader = CSVLoader(file_path=file_path)
+        result = loader.load()
+
+        # Assert
+        assert result == expected_docs
+
+    # Tests that an empty CSV file is handled correctly.
+    def test_csv_loader_load_empty_file(self, mocker: MockerFixture) -> None:
+        # Setup
+        file_path = "test.csv"
+        expected_docs: list = []
+        mocker.patch("builtins.open", mocker.mock_open())
+        mock_csv_reader = mocker.patch("csv.DictReader")
+        mock_csv_reader.return_value = []
+
+        # Exercise
+        loader = CSVLoader(file_path=file_path)
+        result = loader.load()
+
+        # Assert
+        assert result == expected_docs
+
+    # Tests that a CSV file with only one row is handled correctly.
+    def test_csv_loader_load_single_row_file(self, mocker: MockerFixture) -> None:
+        # Setup
+        file_path = "test.csv"
+        expected_docs = [
+            Document(
+                page_content="column1: value1\ncolumn2: value2\ncolumn3: value3",
+                metadata={"source": file_path, "row": 0},
+            )
+        ]
+        mocker.patch("builtins.open", mocker.mock_open())
+        mock_csv_reader = mocker.patch("csv.DictReader")
+        mock_csv_reader.return_value = [
+            {"column1": "value1", "column2": "value2", "column3": "value3"}
+        ]
+
+        # Exercise
+        loader = CSVLoader(file_path=file_path)
+        result = loader.load()
+
+        # Assert
+        assert result == expected_docs
+
+    # Tests that a CSV file with only one column is handled correctly.
+    def test_csv_loader_load_single_column_file(self, mocker: MockerFixture) -> None:
+        # Setup
+        file_path = "test.csv"
+        expected_docs = [
+            Document(
+                page_content="column1: value1",
+                metadata={"source": file_path, "row": 0},
+            ),
+            Document(
+                page_content="column1: value2",
+                metadata={"source": file_path, "row": 1},
+            ),
+            Document(
+                page_content="column1: value3",
+                metadata={"source": file_path, "row": 2},
+            ),
+        ]
+        mocker.patch("builtins.open", mocker.mock_open())
+        mock_csv_reader = mocker.patch("csv.DictReader")
+        mock_csv_reader.return_value = [
+            {"column1": "value1"},
+            {"column1": "value2"},
+            {"column1": "value3"},
+        ]
+
+        # Exercise
+        loader = CSVLoader(file_path=file_path)
+        result = loader.load()
+
+        # Assert
+        assert result == expected_docs