},
		{
			nil,
			[]audit.Stage{audit.StageRequestReceived},
			[]audit.Stage{audit.StageRequestReceived},
		},
	}

	for _, tc := range testCases {
		result := unionStages(tc.s1, tc.s2)
		assert.Len(t, result, len(tc.exp))
		for _, expStage := range tc.exp {
			ok := false
			for _, resultStage := range result {
				if resultStage == expStage {
					ok = true
					break