[test]cli_rich_container_test.go:151 failes to validate stdout

[faycheng]

Ⅰ. Issue Description

sometimes cli_rich_container_test.go:151 fails to validate stdout, here(tavis log) can give us more details.

err=
Command:  /usr/local/bin/pouch exec TestRichContainerInitdWorks ps -ef | grep /sbin/init | awk '{print $1}'
ExitCode: 0
Error:    <nil>
Stdout:   
Stderr:   
Failures:
Expected stdout to contain "1"
----------------------------------------------------------------------
FAIL: /go/src/github.com/alibaba/pouch/test/cli_rich_container_test.go:151: PouchRichContainerSuite.TestRichContainerInitdWorks
/go/src/github.com/alibaba/pouch/test/cli_rich_container_test.go:182:
    c.Assert(checkPidofProcessIsOne(funcname, "/sbin/init"), check.Equals, true)
... obtained bool = false
... expected bool = true

Ⅱ. Describe what happened

Ⅲ. Describe what you expected to happen

Ⅳ. How to reproduce it (as minimally and precisely as possible)

Ⅴ. Anything else we need to know?

Ⅵ. Environment:

• pouch version (use pouch version):
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[Letty5411]

I think this is a flaky test, we may need to enhance or skip it.

[Ace-Tang]

Command:  /usr/local/bin/pouch exec TestRichContainerInitdWorks ps -ef | grep /sbin/init | awk '{print $1}'
ExitCode: 1
Error:    exit status 1
Stdout:   error: garbage option
Usage:
 ps [options]
 Try 'ps --help <simple|list|output|threads|misc|all>'
  or 'ps --help <s|l|o|t|m|a>'
 for additional help text.
For more details see ps(1).
Stderr:   
Failures:
ExitCode was 1 expected 0
Expected no error

it seems like a ps command error, I have no idea whether it has related with my modification, #1128

[allencloud]

Could you take a look on this, whether this is still an issue for PouchContainer? @Letty5411 @Ace-Tang
If not flaky any more, I think we can close this.