feat: establish secure update foundation

cmd/dyndns-web/main_test.go

@@ -0,0 +1,24 @@
+package main
+
+import "testing"
+
+func TestCommandForInvocationKeepsV13ComposeAgentCompatible(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		arguments []string
+		want      string
+	}{
+		{arguments: []string{"/usr/local/bin/domain-control"}, want: "serve"},
+		{arguments: []string{"/usr/local/bin/domain-control", "update-agent"}, want: "update-agent"},
+		{arguments: []string{"/usr/local/bin/domain-control", "healthcheck"}, want: "healthcheck"},
+		{arguments: []string{"/usr/local/bin/update-agent"}, want: "update-agent"},
+		{arguments: []string{"/usr/local/bin/update-agent", "serve"}, want: "update-agent"},
+		{arguments: []string{"/usr/local/bin/domain-control", "serve", "extra"}, want: "invalid"},
+		{arguments: nil, want: "invalid"},
+	}
+	for _, test := range tests {
+		if got := commandForInvocation(test.arguments); got != test.want {
+			t.Errorf("commandForInvocation(%q) = %q; want %q", test.arguments, got, test.want)
+		}
+	}
+}