import subprocess

def _runcmd(ctx, argv):
    p = subprocess.Popen(argv, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = p.communicate("")
    ctx['stdout'] = stdout
    ctx['stderr'] = stderr
    ctx['exit'] = p.returncode

def run_echo_without_args(ctx):
    _runcmd(ctx, ['echo'])

def run_echo_with_args(ctx, args=None):
    _runcmd(ctx, ['echo', args])

def exit_code_is(ctx, exit_code=None):
    assert_eq(ctx['exit'], int(exit_code))

def stdout_is_a_newline(ctx):
    assert_eq(ctx['stdout'], b'\n')

def stdout_is_text(ctx, text=None):
    text += '\n'
    text = text.encode()
    assert_eq(ctx['stdout'], text)

def stderr_is_empty(ctx):
    assert_eq(ctx['stderr'], b'')