msy 0.4.6

Modern musl rsync alternative - Fast, parallel file synchronization
Documentation 
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use msy::compress::{Compression, compress, decompress, should_compress_adaptive};
use std::fs;
use tempfile::TempDir;

#[test]
fn test_compression_end_to_end() {
	// Simulate file transfer with compression
	let source_dir = TempDir::new().unwrap();
	let dest_dir = TempDir::new().unwrap();

	// Create test file with compressible data (>1MB to trigger compression)
	let source_file = source_dir.path().join("test.txt");
	let test_data = "This is test data that should compress well. ".repeat(25_000); // ~1.2 MB
	fs::write(&source_file, &test_data).unwrap();

	let file_size = test_data.len() as u64;

	// 1. Decide if we should compress
	let compression = should_compress_adaptive(
		source_file.to_str().unwrap(),
		file_size,
		false, // Not local (simulate network)
		None,  // No speed info
	);

	assert_eq!(compression, Compression::Zstd, "Should use Zstd for network transfers");

	// 2. Read source file
	let source_data = fs::read(&source_file).unwrap();

	// 3. Compress data
	let compressed = compress(&source_data, compression).unwrap();

	// Verify compression actually reduces size
	let compression_ratio = compressed.len() as f64 / source_data.len() as f64;
	assert!(compression_ratio < 0.5, "Should compress to less than 50% for repetitive data");
	println!("Compression ratio: {:.1}% ({}KB -> {}KB)", compression_ratio * 100.0, source_data.len() / 1024, compressed.len() / 1024);

	// 4. Simulate transfer (just write compressed data)
	let dest_file = dest_dir.path().join("test.txt.compressed");
	fs::write(&dest_file, &compressed).unwrap();

	// 5. Read transferred data
	let transferred = fs::read(&dest_file).unwrap();

	// 6. Decompress
	let decompressed = decompress(&transferred, compression).unwrap();

	// 7. Verify correctness
	assert_eq!(decompressed, source_data, "Decompressed data should match original");
	println!("✓ Compression integration test passed");
}

#[test]
fn test_compression_skip_precompressed() {
	// Verify we don't compress already-compressed files
	let compression = should_compress_adaptive(
		"video.mp4",
		10_000_000, // 10 MB
		false,      // Network transfer
		None,
	);

	assert_eq!(compression, Compression::None, "Should not compress mp4 files");
}

#[test]
fn test_compression_skip_small_files() {
	// Verify we don't compress small files
	let compression = should_compress_adaptive(
		"small.txt",
		512_000, // 500 KB
		false,   // Network transfer
		None,
	);

	assert_eq!(compression, Compression::None, "Should not compress files < 1MB");
}

#[test]
fn test_compression_skip_local() {
	// Verify we don't compress local transfers
	let compression = should_compress_adaptive(
		"large.txt",
		10_000_000, // 10 MB
		true,       // Local transfer
		None,
	);

	assert_eq!(compression, Compression::None, "Should not compress local transfers");
}

#[test]
fn test_compression_performance() {
	use std::time::Instant;

	// Create 10MB of compressible data
	let data: Vec<u8> = "ABCDEFGH".repeat(1_250_000).into_bytes();

	// Benchmark Zstd compression
	let start = Instant::now();
	let compressed = compress(&data, Compression::Zstd).unwrap();
	let duration = start.elapsed();

	let throughput = (data.len() as f64 / duration.as_secs_f64()) / 1_000_000_000.0; // GB/s
	let ratio = compressed.len() as f64 / data.len() as f64;

	println!("Zstd Performance:");
	println!("  Throughput: {:.2} GB/s", throughput);
	println!("  Ratio: {:.1}%", ratio * 100.0);
	println!("  Size: {} KB -> {} KB", data.len() / 1024, compressed.len() / 1024);

	// Verify it's reasonably fast (relaxed threshold for CI environments)
	// Local benchmarks show 8+ GB/s, but CI runners vary (0.5-2 GB/s)
	assert!(throughput > 0.3, "Zstd should compress at >0.3 GB/s, got {:.2} GB/s", throughput);
}