Go already has RSpec!

main.go

package main

import (
  "testing"
  "github.com/stretchr/testify/assert"
)

func TestMain(m *testing.M) {
  // before spec
  err := m.Run()
  // after spec
  os.Exist(err)
}

func TestGetBook(t *testing.T) {
  t.Run("ok", func (t *testing.T) {
    // ....
    assert.Equal(t, http.StatusOK, res.Code)
  }

  t.Run("unauthorized", func (t *testing.T) {
    // ....
    assert.Equal(t, http.StatusUnauthorized, res.Code)
  }

  // etc
}

BTW, the before spec is only run once before all specs/tests, not before each.