move the assertions outside of the goroutine

Signed-off-by: Shijiang Wei <mountkin@gmail.com>

integration-cli/docker_api_exec_resize_test.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"sync"
 
 	"github.com/go-check/check"
 )
@@ -28,53 +29,75 @@ func (s *DockerSuite) TestExecResizeImmediatelyAfterExecStart(c *check.C) {
 	name := "exec_resize_test"
 	dockerCmd(c, "run", "-d", "-i", "-t", "--name", name, "--restart", "always", "busybox", "/bin/sh")
 
-	// The panic happens when daemon.ContainerExecStart is called but the
-	// container.Exec is not called.
-	// Because the panic is not 100% reproducible, we send the requests concurrently
-	// to increase the probability that the problem is triggered.
-	n := 10
-	ch := make(chan struct{})
-	for i := 0; i < n; i++ {
-		go func() {
-			defer func() {
-				ch <- struct{}{}
-			}()
+	testExecResize := func() error {
+		data := map[string]interface{}{
+			"AttachStdin": true,
+			"Cmd":         []string{"/bin/sh"},
+		}
+		uri := fmt.Sprintf("/containers/%s/exec", name)
+		status, body, err := sockRequest("POST", uri, data)
+		if err != nil {
+			return err
+		}
+		if status != http.StatusCreated {
+			return fmt.Errorf("POST %s is expected to return %d, got %d", uri, http.StatusCreated, status)
+		}
 
-			data := map[string]interface{}{
-				"AttachStdin": true,
-				"Cmd":         []string{"/bin/sh"},
-			}
-			status, body, err := sockRequest("POST", fmt.Sprintf("/containers/%s/exec", name), data)
-			c.Assert(err, check.IsNil)
-			c.Assert(status, check.Equals, http.StatusCreated)
+		out := map[string]string{}
+		err = json.Unmarshal(body, &out)
+		if err != nil {
+			return fmt.Errorf("ExecCreate returned invalid json. Error: %q", err.Error())
+		}
 
-			out := map[string]string{}
-			err = json.Unmarshal(body, &out)
-			c.Assert(err, check.IsNil)
+		execID := out["Id"]
+		if len(execID) < 1 {
+			return fmt.Errorf("ExecCreate got invalid execID")
+		}
 
-			execID := out["Id"]
-			if len(execID) < 1 {
-				c.Fatal("ExecCreate got invalid execID")
-			}
+		payload := bytes.NewBufferString(`{"Tty":true}`)
+		conn, _, err := sockRequestHijack("POST", fmt.Sprintf("/exec/%s/start", execID), payload, "application/json")
+		if err != nil {
+			return fmt.Errorf("Failed to start the exec: %q", err.Error())
+		}
+		defer conn.Close()
 
-			payload := bytes.NewBufferString(`{"Tty":true}`)
-			conn, _, err := sockRequestHijack("POST", fmt.Sprintf("/exec/%s/start", execID), payload, "application/json")
-			c.Assert(err, check.IsNil)
-			defer conn.Close()
+		_, rc, err := sockRequestRaw("POST", fmt.Sprintf("/exec/%s/resize?h=24&w=80", execID), nil, "text/plain")
+		// It's probably a panic of the daemon if io.ErrUnexpectedEOF is returned.
+		if err == io.ErrUnexpectedEOF {
+			return fmt.Errorf("The daemon might have crashed.")
+		}
 
-			_, rc, err := sockRequestRaw("POST", fmt.Sprintf("/exec/%s/resize?h=24&w=80", execID), nil, "text/plain")
-			// It's probably a panic of the daemon if io.ErrUnexpectedEOF is returned.
-			if err == io.ErrUnexpectedEOF {
-				c.Fatal("The daemon might have crashed.")
-			}
+		if err == nil {
+			rc.Close()
+		}
 
-			if err == nil {
-				rc.Close()
+		// We only interested in the io.ErrUnexpectedEOF error, so we return nil otherwise.
+		return nil
+	}
+
+	// The panic happens when daemon.ContainerExecStart is called but the
+	// container.Exec is not called.
+	// Because the panic is not 100% reproducible, we send the requests concurrently
+	// to increase the probability that the problem is triggered.
+	var (
+		n  = 10
+		ch = make(chan error, n)
+		wg sync.WaitGroup
+	)
+	for i := 0; i < n; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			if err := testExecResize(); err != nil {
+				ch <- err
 			}
 		}()
 	}
 
-	for i := 0; i < n; i++ {
-		<-ch
+	wg.Wait()
+	select {
+	case err := <-ch:
+		c.Fatal(err.Error())
+	default:
 	}
 }