Harrison/gpt4all (#2366)

Co-authored-by: William FH <13333726+hinthornw@users.noreply.github.com>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

tests/integration_tests/llms/test_gpt4all.py

@@ -0,0 +1,34 @@
+# flake8: noqa
+"""Test Llama.cpp wrapper."""
+import os
+from urllib.request import urlretrieve
+
+from langchain.llms import GPT4All
+
+
+def _download_model() -> str:
+    """Download model.
+    From https://the-eye.eu/public/AI/models/nomic-ai/gpt4all/gpt4all-lora-quantized.bin,
+    convert to new ggml format and return model path."""
+    model_url = "https://the-eye.eu/public/AI/models/nomic-ai/gpt4all/gpt4all-lora-quantized.bin"
+    tokenizer_url = "https://huggingface.co/decapoda-research/llama-7b-hf/resolve/main/tokenizer.model"
+    conversion_script = "https://github.com/nomic-ai/pyllamacpp/blob/main/pyllamacpp/scripts/convert_gpt4all.py"
+    local_filename = model_url.split("/")[-1]
+
+    if not os.path.exists("convert_gpt4all.py"):
+        urlretrieve(conversion_script, "convert_gpt4all.py")
+    if not os.path.exists("tokenizer.model"):
+        urlretrieve(tokenizer_url, "tokenizer.model")
+    if not os.path.exists(local_filename):
+        urlretrieve(model_url, local_filename)
+        os.system(f"python convert_gpt4all.py.py . tokenizer.model")
+
+    return local_filename
+
+
+def test_gpt4all_inference() -> None:
+    """Test valid gpt4all inference."""
+    model_path = _download_model()
+    llm = GPT4All(model=model_path)
+    output = llm("Say foo:")
+    assert isinstance(output, str)