Update shim for exec

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

supervisor/sort_test.go

@@ -0,0 +1,69 @@
+package supervisor
+
+import (
+	"os"
+	"sort"
+	"testing"
+
+	"github.com/docker/containerd/runtime"
+	"github.com/opencontainers/specs"
+)
+
+type testProcess struct {
+	id string
+}
+
+func (p *testProcess) ID() string {
+	return p.id
+}
+
+func (p *testProcess) Stdin() string {
+	return ""
+}
+
+func (p *testProcess) Stdout() string {
+	return ""
+}
+
+func (p *testProcess) Stderr() string {
+	return ""
+}
+
+func (p *testProcess) ExitFD() int {
+	return -1
+}
+
+func (p *testProcess) ExitStatus() (int, error) {
+	return -1, nil
+}
+
+func (p *testProcess) Container() runtime.Container {
+	return nil
+}
+
+func (p *testProcess) Spec() specs.Process {
+	return specs.Process{}
+}
+
+func (p *testProcess) Signal(os.Signal) error {
+	return nil
+}
+
+func (p *testProcess) Close() error {
+	return nil
+}
+
+func TestSortProcesses(t *testing.T) {
+	p := []runtime.Process{
+		&testProcess{"ls"},
+		&testProcess{"other"},
+		&testProcess{"init"},
+		&testProcess{"other2"},
+	}
+	s := &processSorter{p}
+	sort.Sort(s)
+
+	if id := p[len(p)-1].ID(); id != "init" {
+		t.Fatalf("expected init but received %q", id)
+	}
+}