Fix duplicate separator on empty description/url (discord). Fixes #1008 (#1035)

Make this work for all possible cases.
Add tests

bridge/discord/handlers.go

@@ -103,7 +103,7 @@ func (b *Bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreat
 	// if we have embedded content add it to text
 	if b.GetBool("ShowEmbeds") && m.Message.Embeds != nil {
 		for _, embed := range m.Message.Embeds {
-			rmsg.Text = rmsg.Text + "embed: " + embed.Title + " - " + embed.Description + " - " + embed.URL + "\n"
+			rmsg.Text += handleEmbed(embed)
 		}
 	}
 
@@ -192,3 +192,33 @@ func (b *Bdiscord) memberRemove(s *discordgo.Session, m *discordgo.GuildMemberRe
 	b.Log.Debugf("<= Message is %#v", rmsg)
 	b.Remote <- rmsg
 }
+
+func handleEmbed(embed *discordgo.MessageEmbed) string {
+	var t []string
+	var result string
+
+	t = append(t, embed.Title)
+	t = append(t, embed.Description)
+	t = append(t, embed.URL)
+
+	i := 0
+	for _, e := range t {
+		if e == "" {
+			continue
+		}
+
+		i++
+		if i == 1 {
+			result += "embed: " + e
+			continue
+		}
+
+		result += " - " + e
+	}
+
+	if result != "" {
+		result += "\n"
+	}
+
+	return result
+}

bridge/discord/handlers_test.go

@@ -0,0 +1,58 @@
+package bdiscord
+
+import (
+	"testing"
+
+	"github.com/matterbridge/discordgo"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHandleEmbed(t *testing.T) {
+	testcases := map[string]struct {
+		embed  *discordgo.MessageEmbed
+		result string
+	}{
+		"allempty": {
+			embed:  &discordgo.MessageEmbed{},
+			result: "",
+		},
+		"one": {
+			embed: &discordgo.MessageEmbed{
+				Title: "blah",
+			},
+			result: "embed: blah\n",
+		},
+		"two": {
+			embed: &discordgo.MessageEmbed{
+				Title:       "blah",
+				Description: "blah2",
+			},
+			result: "embed: blah - blah2\n",
+		},
+		"three": {
+			embed: &discordgo.MessageEmbed{
+				Title:       "blah",
+				Description: "blah2",
+				URL:         "blah3",
+			},
+			result: "embed: blah - blah2 - blah3\n",
+		},
+		"twob": {
+			embed: &discordgo.MessageEmbed{
+				Description: "blah2",
+				URL:         "blah3",
+			},
+			result: "embed: blah2 - blah3\n",
+		},
+		"oneb": {
+			embed: &discordgo.MessageEmbed{
+				URL: "blah3",
+			},
+			result: "embed: blah3\n",
+		},
+	}
+
+	for name, tc := range testcases {
+		assert.Equalf(t, tc.result, handleEmbed(tc.embed), "Testcases %s", name)
+	}
+}