Optimize slow bottleneck test of DockerSuite.TestRunUnshareProc.

This fix tries to improve the time to run TestRunUnshareProc
in #19425.
In this fix goroutines are used to run test cases in parallel to
prevent the test from taking a long time to run.
As the majority of the execution time in the tests is from
multiple executions of 'docker run' and each of which takes
several seconds, parallel executions improve the test time.
Since each 'docker run' is independent, the purpose of the
test is not altered in this fix.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

integration-cli/docker_cli_run_test.go

@@ -3002,29 +3002,51 @@ func (s *DockerSuite) TestRunUnshareProc(c *check.C) {
 	// Not applicable on Windows as uses Unix specific functionality
 	testRequires(c, Apparmor, DaemonIsLinux, NotUserNamespace)
 
-	name := "acidburn"
-	out, _, err := dockerCmdWithError("run", "--name", name, "--security-opt", "seccomp:unconfined", "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "--mount-proc=/proc", "mount")
-	if err == nil ||
-		!(strings.Contains(strings.ToLower(out), "permission denied") ||
-			strings.Contains(strings.ToLower(out), "operation not permitted")) {
-		c.Fatalf("unshare with --mount-proc should have failed with 'permission denied' or 'operation not permitted', got: %s, %v", out, err)
-	}
+	// In this test goroutines are used to run test cases in parallel to prevent the test from taking a long time to run.
+	errChan := make(chan error)
 
-	name = "cereal"
-	out, _, err = dockerCmdWithError("run", "--name", name, "--security-opt", "seccomp:unconfined", "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "mount", "-t", "proc", "none", "/proc")
-	if err == nil ||
-		!(strings.Contains(strings.ToLower(out), "mount: cannot mount none") ||
-			strings.Contains(strings.ToLower(out), "permission denied")) {
-		c.Fatalf("unshare and mount of /proc should have failed with 'mount: cannot mount none' or 'permission denied', got: %s, %v", out, err)
-	}
+	go func() {
+		name := "acidburn"
+		out, _, err := dockerCmdWithError("run", "--name", name, "--security-opt", "seccomp:unconfined", "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "--mount-proc=/proc", "mount")
+		if err == nil ||
+			!(strings.Contains(strings.ToLower(out), "permission denied") ||
+				strings.Contains(strings.ToLower(out), "operation not permitted")) {
+			errChan <- fmt.Errorf("unshare with --mount-proc should have failed with 'permission denied' or 'operation not permitted', got: %s, %v", out, err)
+		} else {
+			errChan <- nil
+		}
+	}()
+
+	go func() {
+		name := "cereal"
+		out, _, err := dockerCmdWithError("run", "--name", name, "--security-opt", "seccomp:unconfined", "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "mount", "-t", "proc", "none", "/proc")
+		if err == nil ||
+			!(strings.Contains(strings.ToLower(out), "mount: cannot mount none") ||
+				strings.Contains(strings.ToLower(out), "permission denied")) {
+			errChan <- fmt.Errorf("unshare and mount of /proc should have failed with 'mount: cannot mount none' or 'permission denied', got: %s, %v", out, err)
+		} else {
+			errChan <- nil
+		}
+	}()
 
 	/* Ensure still fails if running privileged with the default policy */
-	name = "crashoverride"
-	out, _, err = dockerCmdWithError("run", "--privileged", "--security-opt", "seccomp:unconfined", "--security-opt", "apparmor:docker-default", "--name", name, "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "mount", "-t", "proc", "none", "/proc")
-	if err == nil ||
-		!(strings.Contains(strings.ToLower(out), "mount: cannot mount none") ||
-			strings.Contains(strings.ToLower(out), "permission denied")) {
-		c.Fatalf("privileged unshare with apparmor should have failed with 'mount: cannot mount none' or 'permission denied', got: %s, %v", out, err)
+	go func() {
+		name := "crashoverride"
+		out, _, err := dockerCmdWithError("run", "--privileged", "--security-opt", "seccomp:unconfined", "--security-opt", "apparmor:docker-default", "--name", name, "debian:jessie", "unshare", "-p", "-m", "-f", "-r", "mount", "-t", "proc", "none", "/proc")
+		if err == nil ||
+			!(strings.Contains(strings.ToLower(out), "mount: cannot mount none") ||
+				strings.Contains(strings.ToLower(out), "permission denied")) {
+			errChan <- fmt.Errorf("privileged unshare with apparmor should have failed with 'mount: cannot mount none' or 'permission denied', got: %s, %v", out, err)
+		} else {
+			errChan <- nil
+		}
+	}()
+
+	for i := 0; i < 3; i++ {
+		err := <-errChan
+		if err != nil {
+			c.Fatal(err)
+		}
 	}
 }