v/vlib/log/file_log_test.v

import os
import log
import rand

fn test_reopen() {
	if os.user_os() == 'windows' && os.getenv('SKIP_TEST_REOPEN') == '' {
		eprintln('skip renaming and reopening a log file on windows')
		exit(0)
	}
	lfolder := os.join_path(os.vtmp_dir(), rand.ulid())
	lpath1 := os.join_path(lfolder, 'current.log')
	lpath2 := os.join_path(lfolder, 'current.log.2')
	os.mkdir_all(lfolder)!

	dump(lfolder)
	mut l := log.new_thread_safe_log()
	l.set_level(.debug)
	l.set_full_logpath(lpath1)
	l.warn('one warning')
	l.error('one error')
	// simulate a log rotation, by moving the log file
	os.rename(lpath1, lpath2)!
	l.warn('another warning')
	// call reopen, note that the message from above, should be in the new file lpath2:
	l.reopen()!
	l.warn('third warning')
	l.flush()
	l.close()
	// os.system('ls -la $lpath1 $lpath2')
	lcontent1 := os.read_file(lpath1)!
	lcontent2 := os.read_file(lpath2)!
	assert lcontent1.len > 0
	assert lcontent2.len > 0
	// the rotated log should have all messages before the l.reopen() call:
	assert lcontent2.contains('one warning')
	assert lcontent2.contains('one error')
	assert lcontent2.contains('another warning')
	// the log file that was reopened, should have only the new message:
	assert lcontent1.contains('third warning')
	assert !lcontent1.contains('one warning')

	os.rmdir_all(lfolder) or {}
}

fn test_set_always_flush() {
	log.set_level(.debug)
	lfolder := os.join_path(os.vtmp_dir(), rand.ulid())
	lpath1 := os.join_path(lfolder, 'current.log')
	os.mkdir_all(lfolder)!
	defer {
		os.rmdir_all(lfolder) or {}
	}
	dump(lfolder)
	mut l := log.Log{}
	l.set_level(.info)
	l.set_full_logpath(lpath1)
	l.set_always_flush(true)
	l.warn('one warning')
	l.info('one info message')
	l.error('one error')
	l.close()
	lcontent1 := os.read_file(lpath1)!
	assert lcontent1.len > 0
	assert lcontent1.contains('one warning')
	assert lcontent1.contains('one error')
	assert lcontent1.contains('one info message')
}