Add tests lost during PR 1320.

The tests part of this change were originally in PR 1320 but got lost
during one of the rebases. Let's bring them back in.

provider/marathon/marathon_test.go

@@ -337,6 +337,62 @@ func TestMarathonLoadConfig(t *testing.T) {
 				},
 			},
 		},
+		{
+			applications: &marathon.Applications{
+				Apps: []marathon.Application{
+					{
+						ID:    "/testHealthCheck",
+						Ports: []int{80},
+						Labels: &map[string]string{
+							labelBackendHealthCheckPath:     "/path",
+							labelBackendHealthCheckInterval: "5m",
+						},
+					},
+				},
+			},
+			tasks: &marathon.Tasks{
+				Tasks: []marathon.Task{
+					{
+						ID:    "testHealthCheck",
+						AppID: "/testHealthCheck",
+						Host:  "127.0.0.1",
+						Ports: []int{80},
+						IPAddresses: []*marathon.IPAddress{
+							{
+								IPAddress: "127.0.0.1",
+								Protocol:  "tcp",
+							},
+						},
+					},
+				},
+			},
+			expectedFrontends: map[string]*types.Frontend{
+				"frontend-testHealthCheck": {
+					Backend:        "backend-testHealthCheck",
+					PassHostHeader: true,
+					EntryPoints:    []string{},
+					Routes: map[string]types.Route{
+						"route-host-testHealthCheck": {
+							Rule: "Host:testHealthCheck.docker.localhost",
+						},
+					},
+				},
+			},
+			expectedBackends: map[string]*types.Backend{
+				"backend-testHealthCheck": {
+					Servers: map[string]types.Server{
+						"server-testHealthCheck": {
+							URL:    "http://127.0.0.1:80",
+							Weight: 0,
+						},
+					},
+					HealthCheck: &types.HealthCheck{
+						Path:     "/path",
+						Interval: "5m",
+					},
+				},
+			},
+		},
 	}
 
 	for _, c := range cases {