Race condition (fail) in tests.test_spawn.PtyTestCase.test_spawn_sh_unicode

[jquast]

The test is likely at fault. It is attempting to see its own keyboard input in output, but the prompt is displaying late, causing the familiar "input echo intermittently spanned in output" condition:

AssertionError: assert 'echo $ENV_KEY; exit 0' in 'echo $EN(teamcity-pexpect)(teamcity-pexpect)V_KEY; exit 0\r\nenv_value\r\n' 

Full output and link

self = <tests.test_spawn.PtyTestCase testMethod=test_spawn_sh_unicode>
ptyp = <class 'ptyprocess.ptyprocess.PtyProcessUnicode'>
cmd = 'echo $ENV_KEY; exit 0\n'
outp = 'echo $EN(teamcity-pexpect)(teamcity-pexpect)V_KEY; exit 0\r\nenv_value\r\n'
env_value = 'env_value'

    def _spawn_sh(self, ptyp, cmd, outp, env_value):
        # given,
        p = ptyp.spawn(['sh'], env=self.env)
        p.write(cmd)

        # exercise,
        while True:
            try:
                outp += p.read()
            except EOFError:
                break

        # verify, input is echo to output
>       assert cmd.strip() in outp
E       AssertionError: assert 'echo $ENV_KEY; exit 0' in 'echo $EN(teamcity-pexpect)(teamcity-pexpect)V_KEY; exit 0\r\nenv_value\r\n'
E        +  where 'echo $ENV_KEY; exit 0' = <built-in method strip of str object at 0x7f2231b5f540>()
E        +    where <built-in method strip of str object at 0x7f2231b5f540> = 'echo $ENV_KEY; exit 0\n'.strip

https://teamcity-master.pexpect.org/viewLog.html?buildId=13605&buildTypeId=Pexpect_LinuxBuild&tab=buildLog

[takluyver]

I guess we need to add some kind of wait (either sleep or check for a condition) to ensure the prompt is displayed before we send input.