main.go

package main

type KeyPair struct {
	Key   string
	Value []byte
}

type KeyStore interface {
	Get(k string) (*KeyPair, error)
}

type MockKeyStore struct {
	Dict map[string][]byte
}

func NewRedisKeyStore() {
	return &RedisKeyStore{
		r: redis.Redis{},
	}
}

func (rks *RedisKeyStore) Get(k string) (*KeyPair, error) {
	rkvp, err := rks.r.Get(k)
	if err != nil {
		return nil, err
	}

	return &KeyPair{
		Key:   rkvp.Key,
		Value: rkvp.Value,
	}, nil
}

func NewMockKeyStore() {
	return &MockKeyStore{
		Dict: map[string][]byte{},
	}
}

func (mks *MockKeyStore) Get(k string) (*KeyPair, error) {
	return &KeyPair{Key: k, Value: mks.Dict[k]}, nil
}

This is a great piece for a beginner in programming and TDD. In all languages I have tried Go is the easiest to unit test and this just made it easier. Now my interfaces know what to do in my code.