scenarios := []struct {
			mode     string
			expected string
			musthave []string
		}{
			{
				mode:     "simple",
				expected: "bar foo",
			},
			{
				mode:     "goodexit",
				expected: "orange apple",
			},
			{
				mode:     "badexit",
				expected: "blub blix",
			},
			{
				mode: "panics",
				musthave: []string{
					"fatal error: exit hook invoked panic",
					"main.testPanics",

type Constraint uint8

const (
	MustNotHave Constraint = iota
	MayHave
	MustHave
)

// UserGoReqs is a common requirement among events that are running
// or are close to running user code.