force run container detached if container CreateCommand missing the detach param

the podman generated systemd service file has `Type=forking` service,
so the command after `ExecStart=` should not run in front.
if someone created a container and has the detach(`-d`) param missing
like this
```
podman create --name ngxdemo -P nginxdemos/hello
```
and generate the file with `--new` param:
```
podman generate systemd --name --new ngxdemo
```
because `podman run xxx` has no `-d` param,
so the container is not run in background and nerver exit.
and systemd will fail to start the service:
```
sudo systemctl start container-ngxdemo.service
Job for container-ngxdemo.service failed because a timeout was exceeded.
See "systemctl status container-ngxdemo.service" and "journalctl -xe" for details.
```

Signed-off-by: 荒野無燈 <ttys3@outlook.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/test/e2e/generate_systemd_test.go b/test/e2e/generate_systemd_test.go
index 31131a68b..e5ab0b854 100644
--- a/test/e2e/generate_systemd_test.go
+++ b/test/e2e/generate_systemd_test.go
@@ -195,6 +195,34 @@ var _ = Describe("Podman generate systemd", func() {
 		Expect(found).To(BeTrue())
 	})
 
+	It("podman generate systemd --new without explicit detaching param", func() {
+		n := podmanTest.Podman([]string{"create", "--name", "foo", "alpine", "top"})
+		n.WaitWithDefaultTimeout()
+		Expect(n.ExitCode()).To(Equal(0))
+
+		session := podmanTest.Podman([]string{"generate", "systemd", "--timeout", "42", "--name", "--new", "foo"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		// Grepping the output (in addition to unit tests)
+		found, _ := session.GrepString("--cgroups=no-conmon -d")
+		Expect(found).To(BeTrue())
+	})
+
+	It("podman generate systemd --new with explicit detaching param in middle", func() {
+		n := podmanTest.Podman([]string{"create", "--name", "foo", "-d", "alpine", "top"})
+		n.WaitWithDefaultTimeout()
+		Expect(n.ExitCode()).To(Equal(0))
+
+		session := podmanTest.Podman([]string{"generate", "systemd", "--timeout", "42", "--name", "--new", "foo"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+
+		// Grepping the output (in addition to unit tests)
+		found, _ := session.GrepString("--name foo -d alpine top")
+		Expect(found).To(BeTrue())
+	})
+
 	It("podman generate systemd --new pod", func() {
 		n := podmanTest.Podman([]string{"pod", "create", "--name", "foo"})
 		n.WaitWithDefaultTimeout()