Harrison/big query (#2100)

Co-authored-by: lu-cashmoney <lucas.corley@gmail.com>

tests/integration_tests/document_loaders/test_bigquery.py

@@ -0,0 +1,50 @@
+import pytest
+
+from langchain.document_loaders.bigquery import BigQueryLoader
+
+try:
+    from google.cloud import bigquery  # noqa: F401
+
+    bigquery_installed = True
+except ImportError:
+    bigquery_installed = False
+
+
+@pytest.mark.skipif(not bigquery_installed, reason="bigquery not installed")
+def test_bigquery_loader_no_options() -> None:
+    loader = BigQueryLoader("SELECT 1 AS a, 2 AS b")
+    docs = loader.load()
+
+    assert len(docs) == 1
+    assert docs[0].page_content == "a: 1\nb: 2"
+    assert docs[0].metadata == {}
+
+
+@pytest.mark.skipif(not bigquery_installed, reason="bigquery not installed")
+def test_bigquery_loader_page_content_columns() -> None:
+    loader = BigQueryLoader(
+        "SELECT 1 AS a, 2 AS b UNION ALL SELECT 3 AS a, 4 AS b",
+        page_content_columns=["a"],
+    )
+    docs = loader.load()
+
+    assert len(docs) == 2
+    assert docs[0].page_content == "a: 1"
+    assert docs[0].metadata == {}
+
+    assert docs[1].page_content == "a: 3"
+    assert docs[1].metadata == {}
+
+
+@pytest.mark.skipif(not bigquery_installed, reason="bigquery not installed")
+def test_bigquery_loader_metadata_columns() -> None:
+    loader = BigQueryLoader(
+        "SELECT 1 AS a, 2 AS b",
+        page_content_columns=["a"],
+        metadata_columns=["b"],
+    )
+    docs = loader.load()
+
+    assert len(docs) == 1
+    assert docs[0].page_content == "a: 1"
+    assert docs[0].metadata == {"b": 2}