Add another test case and refactor

Author: mattwynne

cmd/latest.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 
+	"github.com/rcmachado/changelog/chg"
 	"github.com/rcmachado/changelog/parser"
 	"github.com/spf13/cobra"
 )
@@ -20,13 +21,23 @@ func newLatestCmd(iostreams *IOStreams) *cobra.Command {
 				cmd.SilenceUsage = true
 				return fmt.Errorf("There are no versions in the changelog yet")
 			}
-			if len(changelog.Versions) == 1 && changelog.Versions[0].Name == "Unreleased" {
+			releasedVersions := releasedVersions(changelog)
+			if len(releasedVersions) == 0 {
 				cmd.SilenceUsage = true
 				return fmt.Errorf("There are no released versions in the changelog yet")
 			}
-			v := changelog.Versions[1]
+			v := releasedVersions[0]
 			io.WriteString(iostreams.Out, v.Name+"\n")
 			return nil
 		},
 	}
 }
+
+func releasedVersions(changelog *chg.Changelog) (result []chg.Version) {
+	for _, version := range changelog.Versions {
+		if version.Name != "Unreleased" {
+			result = append(result, *version)
+		}
+	}
+	return
+}

cmd/latest_test.go

@@ -29,6 +29,27 @@ func TestLatestCmdShowsLatestReleasedVersion(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, expected, string(out.Bytes()))
 }
+func TestLatestCmdShowsLatestReleasedVersionEvenWhenNoUnreleased(t *testing.T) {
+	changelog, err := ioutil.ReadFile("testdata/legacy-changelog.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `1.0.0
+`
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  bytes.NewBuffer(changelog),
+		Out: out,
+	}
+
+	cmd := newLatestCmd(iostreams)
+	_, err = cmd.ExecuteC()
+
+	assert.Nil(t, err)
+	assert.Equal(t, expected, string(out.Bytes()))
+}
 
 func TestLatestCmdError(t *testing.T) {
 	changelog, err := ioutil.ReadFile("testdata/empty-changelog.md")

cmd/testdata/legacy-changelog.md

@@ -0,0 +1,18 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
+
+This is an example of a legacy changelog we might have inherited that hasn't been properly formatted and doesn't have an Unreleased section.
+
+## [1.0.0] - 2020-01-08
+### Added
+- Item 1
+- Item 2
+
+### Changed
+- Item 3
+
+[1.0.0]: https://github.com/rcmachado/changelog/compare/ae761ff...1.0.0