func Greet(who string) {
	fmt.Printf("Hello, %s!\n", who)
}
`
	const test = `
package p_test

// This comment is associated with the ExampleGreet_world example.
func ExampleGreet_world() {
	Greet("world")
}
`

	// Create the AST by parsing src and test.
	fset := token.NewFileSet()
	files := []*ast.File{
		mustParse(fset, "src.go", src),