add regression test from @crosbymichael

utils_test.go

@@ -190,3 +190,45 @@ func TestMergeConfig(t *testing.T) {
 		}
 	}
 }
+
+func TestMergeConfigPublicPortNotHonored(t *testing.T) {
+	volumesImage := make(map[string]struct{})
+	volumesImage["/test1"] = struct{}{}
+	volumesImage["/test2"] = struct{}{}
+	configImage := &Config{
+		Dns:       []string{"1.1.1.1", "2.2.2.2"},
+		PortSpecs: []string{"1111", "2222"},
+		Env:       []string{"VAR1=1", "VAR2=2"},
+		Volumes:   volumesImage,
+	}
+
+	volumesUser := make(map[string]struct{})
+	volumesUser["/test3"] = struct{}{}
+	configUser := &Config{
+		Dns:       []string{"3.3.3.3"},
+		PortSpecs: []string{"1111:3333"},
+		Env:       []string{"VAR2=3", "VAR3=3"},
+		Volumes:   volumesUser,
+	}
+
+	MergeConfig(configUser, configImage)
+
+	contains := func(a []string, expect string) bool {
+		for _, p := range a {
+			if p == expect {
+				return true
+			}
+		}
+		return false
+	}
+
+	if !contains(configUser.PortSpecs, "2222") {
+		t.Logf("Expected '2222' Ports: %v", configUser.PortSpecs)
+		t.Fail()
+	}
+
+	if !contains(configUser.PortSpecs, "1111:3333") {
+		t.Logf("Expected '1111:3333' Ports: %v", configUser.PortSpecs)
+		t.Fail()
+	}
+}