"""Tests for YouTube Transcript MCP Server."""
import pytest
from unittest.mock import patch, AsyncMock
from fastmcp import Client
from mcp.types import TextContent
from ytt_mcp import mcp, extract_video_id
class TestExtractVideoId:
"""Test video ID extraction."""
def test_extract_from_watch_url(self) -> None:
"""Test extracting ID from watch URL."""
url = "https://www.youtube.com/watch?v=dQw4w9WgXcQ"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_short_url(self) -> None:
"""Test extracting ID from short URL."""
url = "https://youtu.be/dQw4w9WgXcQ"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_embed_url(self) -> None:
"""Test extracting ID from embed URL."""
url = "https://www.youtube.com/embed/dQw4w9WgXcQ"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_shorts_url(self) -> None:
"""Test extracting ID from shorts URL."""
url = "https://www.youtube.com/shorts/dQw4w9WgXcQ"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_mobile_url(self) -> None:
"""Test extracting ID from mobile URL."""
url = "https://m.youtube.com/watch?v=dQw4w9WgXcQ"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_url_with_timestamp(self) -> None:
"""Test extracting ID from URL with timestamp."""
url = "https://www.youtube.com/watch?v=dQw4w9WgXcQ&t=123s"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_extract_from_url_with_additional_params(self) -> None:
"""Test extracting ID from URL with additional parameters."""
url = "https://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=share&si=abc123"
assert extract_video_id(url) == "dQw4w9WgXcQ"
def test_return_video_id_directly(self) -> None:
"""Test returning video ID when already provided."""
video_id = "dQw4w9WgXcQ"
assert extract_video_id(video_id) == video_id
def test_invalid_url_raises_error(self) -> None:
"""Test that invalid URL raises ValueError."""
with pytest.raises(ValueError, match="Invalid YouTube URL"):
extract_video_id("not-a-valid-url")
def test_invalid_hostname_raises_error(self) -> None:
"""Test that invalid hostname raises ValueError."""
with pytest.raises(ValueError, match="Invalid YouTube URL or video ID"):
extract_video_id("https://invalid-domain.com/watch?v=dQw4w9WgXcQ")
def test_missing_video_id_raises_error(self) -> None:
"""Test that URL without video ID raises ValueError."""
with pytest.raises(ValueError, match="Invalid YouTube URL or video ID"):
extract_video_id("https://www.youtube.com/watch")
def test_invalid_video_id_format_raises_error(self) -> None:
"""Test that URL with invalid video ID format raises ValueError."""
with pytest.raises(ValueError, match="Invalid YouTube URL or video ID"):
extract_video_id("https://www.youtube.com/watch?v=invalid-id")
async def test_youtube_transcript_mcp_server():
"""Test various scenarios for the get_youtube_transcript tool."""
mock_transcript_en = "This is a test transcript"
mock_transcript_fr = "Ceci est une transcription de test en français"
def mock_fetch_side_effect(video_id: str, lang: str | None = None) -> str:
if lang is None or lang == "en":
return mock_transcript_en
elif lang == "fr":
return mock_transcript_fr
else:
raise ValueError(f"Unsupported language: {lang}")
async with Client(mcp) as client:
# Verify available tools
tools = await client.list_tools()
assert len(tools) == 1
assert tools[0].name == "get_youtube_transcript"
with patch(
"ytt_mcp.fetch_youtube_transcript", new_callable=AsyncMock
) as mock_fetch:
mock_fetch.side_effect = mock_fetch_side_effect
# Test default case (no lang parameter)
result = await client.call_tool(
"get_youtube_transcript",
{"url": "https://youtube.com/watch?v=dQw4w9WgXcQ"},
)
assert isinstance(result.content[0], TextContent)
assert result.content[0].text == mock_transcript_en
mock_fetch.assert_called_with("dQw4w9WgXcQ", "en")
# Test explicit English language
result = await client.call_tool(
"get_youtube_transcript",
{"url": "https://youtube.com/watch?v=dQw4w9WgXcQ", "lang": "en"},
)
assert isinstance(result.content[0], TextContent)
assert result.content[0].text == mock_transcript_en
mock_fetch.assert_called_with("dQw4w9WgXcQ", "en")
# Test French transcript
result = await client.call_tool(
"get_youtube_transcript",
{"url": "https://youtube.com/watch?v=dQw4w9WgXcQ", "lang": "fr"},
)
assert isinstance(result.content[0], TextContent)
assert result.content[0].text == mock_transcript_fr
mock_fetch.assert_called_with("dQw4w9WgXcQ", "fr")
# Test invalid language code (Pydantic validation)
with pytest.raises(Exception, match="validation error"):
await client.call_tool(
"get_youtube_transcript",
{
"url": "https://youtube.com/watch?v=dQw4w9WgXcQ",
"lang": "invalid-lang",
},
)
