fastmcp/tests/prompts/test_prompt.py
2025-05-27 19:38:25 -05:00

312 lines
11 KiB
Python

import pytest
from mcp.types import EmbeddedResource, TextResourceContents
from pydantic import FileUrl
from fastmcp.prompts.prompt import (
BaseModel,
Message,
Prompt,
PromptMessage,
TextContent,
)
class MyTestModel(BaseModel):
key: str
value: int
class TestRenderPrompt:
async def test_basic_fn(self):
def fn() -> str:
return "Hello, world!"
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user", content=TextContent(type="text", text="Hello, world!")
)
]
async def test_async_fn(self):
async def fn() -> str:
return "Hello, world!"
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user", content=TextContent(type="text", text="Hello, world!")
)
]
async def test_fn_with_args(self):
async def fn(name: str, age: int = 30) -> str:
return f"Hello, {name}! You're {age} years old."
prompt = Prompt.from_function(fn)
assert await prompt.render(arguments=dict(name="World")) == [
PromptMessage(
role="user",
content=TextContent(
type="text", text="Hello, World! You're 30 years old."
),
)
]
async def test_callable_object(self):
class MyPrompt:
def __call__(self, name: str) -> str:
return f"Hello, {name}!"
prompt = Prompt.from_function(MyPrompt())
assert await prompt.render(arguments=dict(name="World")) == [
PromptMessage(
role="user", content=TextContent(type="text", text="Hello, World!")
)
]
async def test_async_callable_object(self):
class MyPrompt:
async def __call__(self, name: str) -> str:
return f"Hello, {name}!"
prompt = Prompt.from_function(MyPrompt())
assert await prompt.render(arguments=dict(name="World")) == [
PromptMessage(
role="user", content=TextContent(type="text", text="Hello, World!")
)
]
async def test_fn_with_invalid_kwargs(self):
async def fn(name: str, age: int = 30) -> str:
return f"Hello, {name}! You're {age} years old."
prompt = Prompt.from_function(fn)
with pytest.raises(ValueError):
await prompt.render(arguments=dict(age=40))
async def test_fn_returns_message(self):
async def fn() -> PromptMessage:
return PromptMessage(
role="user", content=TextContent(type="text", text="Hello, world!")
)
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user", content=TextContent(type="text", text="Hello, world!")
)
]
async def test_fn_returns_assistant_message(self):
async def fn() -> PromptMessage:
return PromptMessage(
role="assistant", content=TextContent(type="text", text="Hello, world!")
)
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="assistant", content=TextContent(type="text", text="Hello, world!")
)
]
async def test_fn_returns_multiple_messages(self):
expected = [
Message(role="user", content="Hello, world!"),
Message(role="assistant", content="How can I help you today?"),
Message(
role="user",
content="I'm looking for a restaurant in the center of town.",
),
]
async def fn() -> list[PromptMessage]:
return expected
prompt = Prompt.from_function(fn)
assert await prompt.render() == expected
async def test_fn_returns_list_of_strings(self):
expected = [
"Hello, world!",
"I'm looking for a restaurant in the center of town.",
]
async def fn() -> list[str]:
return expected
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(role="user", content=TextContent(type="text", text=t))
for t in expected
]
async def test_fn_returns_resource_content(self):
"""Test returning a message with resource content."""
async def fn() -> PromptMessage:
return PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
)
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
)
]
async def test_fn_returns_mixed_content(self):
"""Test returning messages with mixed content types."""
async def fn() -> list[PromptMessage | str]:
return [
"Please analyze this file:",
PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
),
Message(role="assistant", content="I'll help analyze that file."),
]
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user",
content=TextContent(type="text", text="Please analyze this file:"),
),
PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
),
PromptMessage(
role="assistant",
content=TextContent(type="text", text="I'll help analyze that file."),
),
]
async def test_fn_returns_message_with_resource(self):
"""Test returning a dict with resource content."""
async def fn() -> PromptMessage:
return PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
)
prompt = Prompt.from_function(fn)
assert await prompt.render() == [
PromptMessage(
role="user",
content=EmbeddedResource(
type="resource",
resource=TextResourceContents(
uri=FileUrl("file://file.txt"),
text="File contents",
mimeType="text/plain",
),
),
)
]
async def test_render_with_json_string_list_arg(self):
"""Test that JSON string for a list argument is auto-deserialized."""
def prompt_with_list(my_list: list[int]) -> str:
return f"List sum: {sum(my_list)}"
prompt = Prompt.from_function(prompt_with_list)
rendered_messages = await prompt.render(arguments={"my_list": "[1, 2, 3, 4]"})
assert len(rendered_messages) == 1
assert isinstance(rendered_messages[0].content, TextContent)
assert rendered_messages[0].content.text == "List sum: 10"
async def test_render_with_json_string_dict_arg(self):
"""Test that JSON string for a dict argument is auto-deserialized."""
def prompt_with_dict(my_dict: dict[str, int]) -> str:
return f"Value for 'b': {my_dict.get('b')}"
prompt = Prompt.from_function(prompt_with_dict)
rendered_messages = await prompt.render(
arguments={"my_dict": '{"a": 1, "b": 2}'}
) # escaped JSON string
assert len(rendered_messages) == 1
assert isinstance(rendered_messages[0].content, TextContent)
assert rendered_messages[0].content.text == "Value for 'b': 2"
async def test_render_with_json_string_basemodel_arg(self):
"""Test that JSON string for a Pydantic BaseModel argument is auto-deserialized."""
def prompt_with_model(my_model: MyTestModel) -> str:
return f"Model: {my_model.key}={my_model.value}"
prompt = Prompt.from_function(prompt_with_model)
rendered_messages = await prompt.render(
arguments={"my_model": '{"key": "test", "value": 123}'}
) # escaped JSON string
assert len(rendered_messages) == 1
assert isinstance(rendered_messages[0].content, TextContent)
assert rendered_messages[0].content.text == "Model: test=123"
async def test_render_with_malformed_json_string_arg(self):
"""Test that a malformed JSON string for a list arg is passed as string (and Pydantic errors)."""
def prompt_with_list(my_list: list[int]) -> str:
return f"List sum: {sum(my_list)}"
prompt = Prompt.from_function(prompt_with_list)
with pytest.raises(
ValueError, match="Error rendering prompt prompt_with_list."
):
await prompt.render(arguments={"my_list": "not a valid json list"})
async def test_render_with_non_json_string_for_string_arg(self):
"""Test that a regular string for a string argument is not json.loads-ed."""
def prompt_with_string(my_string: str) -> str:
return f"String: {my_string}"
prompt = Prompt.from_function(prompt_with_string)
rendered_messages = await prompt.render(arguments={"my_string": '{"a": 1}'})
assert len(rendered_messages) == 1
assert isinstance(rendered_messages[0].content, TextContent)
assert rendered_messages[0].content.text == 'String: {"a": 1}'