You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: diff_test.go
    path of file: ./repos/skeema/internal/tengo
    
    the code of the file until where you have to start completion: package tengo

import (
	"testing"
)

f
    
func TestNilObjectDiff(t *testing.T) {
	var td *TableDiff
	expectKey := ObjectKey{}
	if td.ObjectKey() != expectKey {
		t.Errorf("Unexpected object key: %s", td.ObjectKey())
	}
	if td.DiffType() != DiffTypeNone || td.DiffType().String() != "" {
		t.Errorf("Unexpected diff type: %s", td.DiffType())
	}
	if stmt, err := td.Statement(StatementModifiers{}); stmt != "" || err != nil {
		t.Errorf("Unexpected return from Statement: %s / %v", stmt, err)
	}

	var rd *RoutineDiff
	expectKey = ObjectKey{}
	if rd.ObjectKey() != expectKey {
		t.Errorf("Unexpected object key: %s", rd.ObjectKey())
	}
	if rd.DiffType() != DiffTypeNone {
		t.Errorf("Unexpected diff type: %s", rd.DiffType())
	}
	if stmt, err := rd.Statement(StatementModifiers{}); stmt != "" || err != nil {
		t.Errorf("Unexpected return from Statement: %s / %v", stmt, err)
	}
}