Function init_log_capture

pub fn init_log_capture(
    max_level: impl Into<LevelFilter>,
    print_logs: bool,
) -> (LogCapture, impl Subscriber + Send + Sync)

Initialises a log capture utility for testing, with optional log printing.

This function sets up a LogCapture instance to capture logs during test execution. It also configures a tracing_subscriber with the specified maximum log level and a writer that directs logs to LogCapture. If print_logs is enabled, logs up to max_level are also printed to the test output.

Arguments

• max_level - The maximum log level to capture and print, which can be converted into LevelFilter.
• print_logs - If true, logs up to max_level will also be printed to the test output.

Returns

A tuple containing:

• LogCapture: The log capture instance.
• Subscriber: A configured tracing_subscriber that captures logs.

Examples

use sp_tracing::{
    test_log_capture::init_log_capture,
    tracing::{info, subscriber, Level},
};

let (log_capture, subscriber) = init_log_capture(Level::INFO, false);
subscriber::with_default(subscriber, || {
    info!("This log will be captured");
    assert!(log_capture.contains("This log will be captured"));
});

Usage Guide

• If you only need to capture logs for assertions without printing them, use init_log_capture(max_level, false).
• If you need both capturing and printing logs, use init_log_capture(max_level, true).
• If you only need to print logs but not capture them, use sp_tracing::init_for_tests().