Adds a bit of structure

model/config.go

@@ -0,0 +1,25 @@
+package model
+
+import (
+	"io/ioutil"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	BirthdayFile string `yaml:"birthday_file"`
+}
+
+func ReadConfig(path string) (*Config, error) {
+	fileBytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	var config *Config
+	if err := yaml.Unmarshal(fileBytes, &config); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}

model/config_test.go

@@ -0,0 +1,36 @@
+package model
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestReadConfig(t *testing.T) {
+	t.Run("should correctly read a configuration file", func(t *testing.T) {
+		f, err := ioutil.TempFile("", "birthdaybot-")
+		require.NoError(t, err)
+		defer os.Remove(f.Name())
+
+		io.WriteString(f, "---\nbirthday_file: birthday.csv")
+		f.Close()
+
+		config, err := ReadConfig(f.Name())
+		require.NoError(t, err)
+		require.Equal(t, "birthday.csv", config.BirthdayFile)
+	})
+
+	t.Run("should fail if the file doesn't exist", func(t *testing.T) {
+		f, err := ioutil.TempFile("", "birthdaybot-")
+		require.NoError(t, err)
+		f.Close()
+		os.Remove(f.Name())
+
+		config, err := ReadConfig(f.Name())
+		require.Error(t, err)
+		require.Nil(t, config)
+	})
+}