// MustYAML calls GetYAML and panics if an error occurs.
	MustYAML() string

	// Split this source into individual CRDs.
	Split() ([]Source, error)

	// SplitOrFail calls Split and fails if an error occurs.
	SplitOrFail(t test.Failer) []Source

	// MustSplit calls Split and panics if an error occurs.
	MustSplit() []Source

	// Params returns a copy of the parameters for this Source.
	Params() param.Params

func (b *Builder) Source(sources ...Source) *Builder {
	b.t.Helper()
	out := b.Copy()

	for _, s := range sources {
		// Split the source so that we process a single CRD at a time.
		for _, s := range s.SplitOrFail(b.t) {
			// If the caller set namespaces with literal strings, replace with namespace.Instance objects.
			s = replaceNamespaceStrings(s)

			tpl := s.TemplateOrFail(out.t)
			need := tpl.MissingParams(s.Params())