[GH-717] Implement subscription notification for pull request "reopen…

…ed" event (#718)

* [MI-3808] Fix issue: Subscription notification not working for pull request "reopened" event.

* [MI-3808] Added test case for new template

* [MI-3808] Review fix

server/plugin/template.go

@@ -198,6 +198,10 @@ Assignees: {{range $i, $el := .Assignees -}} {{- if $i}}, {{end}}{{template "use
 {{- if .GetPullRequest.GetMerged }} merged
 {{- else }} closed
 {{- end }} by {{template "user" .GetSender}}.
+`))
+
+	template.Must(masterTemplate.New("reopenedPR").Funcs(funcMap).Parse(`
+{{template "repo" .GetRepo}} Pull request {{template "pullRequest" .GetPullRequest}} was reopened by {{template "user" .GetSender}}.
 `))
 
 	template.Must(masterTemplate.New("pullRequestLabelled").Funcs(funcMap).Parse(`

server/plugin/template_test.go

@@ -341,6 +341,22 @@ func TestClosedPRMessageTemplate(t *testing.T) {
 	})
 }
 
+func TestReopenedPRMessageTemplate(t *testing.T) {
+	t.Run("reopened", func(t *testing.T) {
+		expected := `
+[\[mattermost-plugin-github\]](https://github.com/mattermost/mattermost-plugin-github) Pull request [#42 Leverage git-get-head](https://github.com/mattermost/mattermost-plugin-github/pull/42) was reopened by [panda](https://github.com/panda).
+`
+
+		actual, err := renderTemplate("reopenedPR", &github.PullRequestEvent{
+			Repo:        &repo,
+			PullRequest: &pullRequest,
+			Sender:      &user,
+		})
+		require.NoError(t, err)
+		require.Equal(t, expected, actual)
+	})
+}
+
 func TestPullRequestLabelledTemplate(t *testing.T) {
 	expected := `
 #### Leverage git-get-head

server/plugin/webhook.go

@@ -315,7 +315,12 @@ func (p *Plugin) postPullRequestEvent(event *github.PullRequestEvent) {
 	}
 
 	action := event.GetAction()
-	if action != actionOpened && action != actionLabeled && action != actionClosed {
+	switch action {
+	case actionOpened,
+		actionReopened,
+		actionLabeled,
+		actionClosed:
+	default:
 		return
 	}
 
@@ -387,6 +392,16 @@ func (p *Plugin) postPullRequestEvent(event *github.PullRequestEvent) {
 			post.Message = p.sanitizeDescription(newPRMessage)
 		}
 
+		if action == actionReopened {
+			reopenedPRMessage, err := renderTemplate("reopenedPR", event)
+			if err != nil {
+				p.client.Log.Warn("Failed to render template", "error", err.Error())
+				return
+			}
+
+			post.Message = p.sanitizeDescription(reopenedPRMessage)
+		}
+
 		if action == actionClosed {
 			post.Message = closedPRMessage
 		}