func PackageTestAST(path string) (pkg *ast.Package, err error) {
	return parseAndFilterPackages(path, func(k string, v *ast.Package) bool {
		return strings.HasSuffix(k, "_test")
	})
}
PackageTestAST returns the AST of the test package at the given path.
package parseutil
import (
	"errors"
	"go/ast"
	"go/parser"
	"go/token"
	"strings"
)
var ErrTooManyPackages = errors.New("more than one package found in a directory")
func PackageAST(path string) (pkg *ast.Package, err error) {
	return parseAndFilterPackages(path, func(k string, v *ast.Package) bool {
		return !strings.HasSuffix(k, "_test")
	})
}