Add init command

cmd/init.go

@@ -0,0 +1,18 @@
+package cmd
+
+import (
+	"github.com/rcmachado/changelog/chg"
+	"github.com/spf13/cobra"
+)
+
+func newInitCmd(iostreams *IOStreams) *cobra.Command {
+	return &cobra.Command{
+		Use:   "init",
+		Short: "creates a new changelog file",
+		Run: func(cmd *cobra.Command, args []string) {
+			compareURL := "https://github.com/rcmachado/changelog/compare/abcdef...HEAD"
+			c := chg.NewEmptyChangelog(compareURL)
+			c.Render(iostreams.Out)
+		},
+	}
+}

cmd/init_test.go

@@ -0,0 +1,36 @@
+package cmd
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestInitCmd(t *testing.T) {
+	expected := `# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+### Added
+- First commit
+
+[Unreleased]: https://github.com/rcmachado/changelog/compare/abcdef...HEAD
+`
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  nil,
+		Out: out,
+	}
+
+	cmd := newInitCmd(iostreams)
+	_, err := cmd.ExecuteC()
+
+	assert.Nil(t, err)
+	assert.Equal(t, expected, string(out.Bytes()))
+}

cmd/root.go

@@ -65,6 +65,9 @@ func openFileOrExit(fs *pflag.FlagSet, option string, flag int, defaultIfDash *o
 func init() {
 	ioStreams = &IOStreams{}
 
+	initCmd := newInitCmd(ioStreams)
+	rootCmd.AddCommand(initCmd)
+
 	fmtCmd := NewFmtCmd(ioStreams)
 	rootCmd.AddCommand(fmtCmd)