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Testing Rich Logging Handler Implementation in Textualize/rich

This test suite validates the Rich library’s logging functionality, specifically testing the RichHandler implementation for Python’s logging module. It focuses on exception handling, console output formatting, and markup capabilities.

Test Coverage Overview

The test suite provides comprehensive coverage of Rich’s logging handler functionality:

Exception handling and traceback formatting
Console output with various configurations
Markup and highlighting capabilities
Edge cases like None stdout/stderr scenarios

Implementation Analysis

The testing approach utilizes pytest fixtures and mocking to validate logging behavior:

Console output capture using StringIO
Monkeypatch for system stream manipulation
Custom formatter configurations
Rich-specific features like tracebacks and markup handling

Technical Details

Testing infrastructure includes:

pytest framework with skip decorators
Rich Console and RichHandler classes
Python’s built-in logging module
StringIO for output capture
Custom console configurations for width, color, and terminal settings

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases with clear assertions
Platform-specific test handling
Proper cleanup in test teardown
Comprehensive error scenario coverage
Clear test naming conventions

textualize/rich

tests/test_logging.py

            
import io
import os
import logging
from typing import Optional

import pytest

from rich.console import Console
from rich.logging import RichHandler

handler = RichHandler(
    console=Console(
        file=io.StringIO(),
        force_terminal=True,
        width=80,
        color_system="truecolor",
        _environ={},
    ),
    enable_link_path=False,
)

logging.basicConfig(
    level="NOTSET", format="%(message)s", datefmt="[DATE]", handlers=[handler]
)
log = logging.getLogger("rich")


skip_win = pytest.mark.skipif(
    os.name == "nt",
    reason="rendered differently on windows",
)


@skip_win
def test_exception():
    console = Console(
        file=io.StringIO(),
        force_terminal=True,
        width=140,
        color_system=None,
        _environ={},
    )
    handler_with_tracebacks = RichHandler(
        console=console, enable_link_path=False, rich_tracebacks=True
    )
    formatter = logging.Formatter("FORMATTER %(message)s %(asctime)s")
    handler_with_tracebacks.setFormatter(formatter)
    log.addHandler(handler_with_tracebacks)
    log.error("foo")
    try:
        1 / 0
    except ZeroDivisionError:
        log.exception("message")

    render = handler_with_tracebacks.console.file.getvalue()
    print(render)

    assert "FORMATTER foo" in render
    assert "ZeroDivisionError" in render
    assert "message" in render
    assert "division by zero" in render


def test_exception_with_extra_lines():
    console = Console(
        file=io.StringIO(),
        force_terminal=True,
        width=140,
        color_system=None,
        _environ={},
    )
    handler_extra_lines = RichHandler(
        console=console,
        enable_link_path=False,
        markup=True,
        rich_tracebacks=True,
        tracebacks_extra_lines=5,
    )
    log.addHandler(handler_extra_lines)

    try:
        1 / 0
    except ZeroDivisionError:
        log.exception("message")

    render = handler_extra_lines.console.file.getvalue()
    print(render)

    assert "ZeroDivisionError" in render
    assert "message" in render
    assert "division by zero" in render


def test_stderr_and_stdout_are_none(monkeypatch):
    # This test is specifically to handle cases when using pythonw on
    # windows and stderr and stdout are set to None.
    # See https://bugs.python.org/issue13807

    monkeypatch.setattr("sys.stdout", None)
    monkeypatch.setattr("sys.stderr", None)

    console = Console(_environ={})
    target_handler = RichHandler(console=console)
    actual_record: Optional[logging.LogRecord] = None

    def mock_handle_error(record):
        nonlocal actual_record
        actual_record = record

    target_handler.handleError = mock_handle_error
    log.addHandler(target_handler)

    try:
        1 / 0
    except ZeroDivisionError:
        log.exception("message")

    finally:
        log.removeHandler(target_handler)

    assert actual_record is not None
    assert "message" in actual_record.msg


def test_markup_and_highlight():
    console = Console(
        file=io.StringIO(),
        force_terminal=True,
        width=140,
        color_system="truecolor",
        _environ={},
    )
    handler = RichHandler(console=console)

    # Check defaults are as expected
    assert handler.highlighter
    assert not handler.markup

    formatter = logging.Formatter("FORMATTER %(message)s %(asctime)s")
    handler.setFormatter(formatter)
    log.addHandler(handler)

    log_message = "foo 3.141 127.0.0.1 [red]alert[/red]"

    log.error(log_message)
    render_fancy = handler.console.file.getvalue()
    assert "FORMATTER" in render_fancy
    assert log_message not in render_fancy
    assert "red" in render_fancy

    handler.console.file = io.StringIO()
    log.error(log_message, extra={"markup": True})
    render_markup = handler.console.file.getvalue()
    assert "FORMATTER" in render_markup
    assert log_message not in render_markup
    assert "red" not in render_markup

    handler.console.file = io.StringIO()
    log.error(log_message, extra={"highlighter": None})
    render_plain = handler.console.file.getvalue()
    assert "FORMATTER" in render_plain
    assert log_message in render_plain


if __name__ == "__main__":
    render = make_log()
    print(render)
    print(repr(render))