Example of agenda testing

example.go

package example

import "errors"

type Movie struct {
	TotalTime   int  `json:"total_time"`
	CurrentTime int  `json:"current_time"`
	IsPlaying   bool `json:"is_playing"`
}

func (m *Movie) Rewind() {
	m.CurrentTime = 0
}

func (m *Movie) Play() error {
	if m.IsPlaying {
		return errors.New("Movie is already playing")
	}
	m.IsPlaying = true
	return nil
}

example_test.go

package example

import (
	"encoding/json"
	"testing"

	"github.com/iafan/agenda"
)

func TestMovie(t *testing.T) {
	agenda.Run(t, ".", func(path string, data []byte) ([]byte, error) {
		type MovieTestResult struct {
			M   *Movie      `json:"movie"`
			Err interface{} `json:"play_error"`
		}

		in := make([]*Movie, 0)

		if err := json.Unmarshal(data, &in); err != nil {
			return nil, err
		}

		out := make([]*MovieTestResult, len(in))

		for i, m := range in {
			// Rewind() method modifies the struct itself
			m.Rewind()
			// m.Play returns the error which we want to compare across test runs
			err := m.Play()

			// prepare the output data structure
			// 1) we want to test that the struct state matches our expectations
			// 2) we want to test that the returned error (nil or string value)
			// matches our expectations
			out[i] = &MovieTestResult{m, agenda.SerializableError(err)}
		}

		return json.MarshalIndent(out, "", "\t")
	})
}

test_data.json

[
	{"total_time":100,"current_time":0,"is_playing":false},
	{"total_time":150,"current_time":35,"is_playing":true},
	{"total_time":95,"current_time":4,"is_playing":true},
	{"total_time":125,"current_time":110,"is_playing":false}
]

test_data.json.result

[
	{
		"movie": {
			"total_time": 100,
			"current_time": 0,
			"is_playing": true
		},
		"play_error": null
	},
	{
		"movie": {
			"total_time": 150,
			"current_time": 0,
			"is_playing": true
		},
		"play_error": "Movie is already playing"
	},
	{
		"movie": {
			"total_time": 95,
			"current_time": 0,
			"is_playing": true
		},
		"play_error": "Movie is already playing"
	},
	{
		"movie": {
			"total_time": 125,
			"current_time": 0,
			"is_playing": true
		},
		"play_error": null
	}
]