exec

type Cmd interface {
	// Run runs the command to the completion.
	Run() error
	// CombinedOutput runs the command and returns its combined standard output
	// and standard error. This follows the pattern of package os/exec.
	CombinedOutput() ([]byte, error)
	// Output runs the command and returns standard output, but not standard err
	Output() ([]byte, error)
	SetDir(dir string)
	SetStdin(in io.Reader)
	SetStdout(out io.Writer)
	SetStderr(out io.Writer)
	SetEnv(env []string)

	// StdoutPipe and StderrPipe for getting the process' Stdout and Stderr as
	// Readers
	StdoutPipe() (io.ReadCloser, error)
	StderrPipe() (io.ReadCloser, error)

	// Start and Wait are for running a process non-blocking
	Start() error
	Wait() error

	// Stops the command by sending SIGTERM. It is not guaranteed the
	// process will stop before this function returns. If the process is not
	// responding, an internal timer function will send a SIGKILL to force
	// terminate after 10 seconds.
	Stop()
}

type CodeExitError struct {
	Err  error
	Code int
}

type ExitError interface {
	String() string
	Error() string
	Exited() bool
	ExitStatus() int
}

type ExitErrorWrapper struct {
	*osexec.ExitError
}

type Interface interface {
	// Command returns a Cmd instance which can be used to run a single command.
	// This follows the pattern of package os/exec.
	Command(cmd string, args ...string) Cmd

	// CommandContext returns a Cmd instance which can be used to run a single command.
	//
	// The provided context is used to kill the process if the context becomes done
	// before the command completes on its own. For example, a timeout can be set in
	// the context.
	CommandContext(ctx context.Context, cmd string, args ...string) Cmd

	// LookPath wraps os/exec.LookPath
	LookPath(file string) (string, error)
}