Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/app/download_test.go

@@ -0,0 +1,74 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+)
+
+func TestDownloadFromURL(t *testing.T) {
+	th := Setup(t)
+	defer th.TearDown()
+
+	app := th.App
+	app.Config().PluginSettings.AllowInsecureDownloadURL = model.NewBool(true)
+
+	// To keep track of how many times an endpoint is retried. This needs to be reset
+	// for each test run.
+	retries := 0
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/succeeds-after-retry", func(w http.ResponseWriter, r *http.Request) {
+		if retries < 2 {
+			http.Error(w, "Request Timed out", http.StatusGatewayTimeout)
+			retries++
+			return
+		}
+
+		_, _ = w.Write([]byte("Your request is successful."))
+	})
+
+	mux.HandleFunc("/fails-forever", func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "This would fail forever", http.StatusInternalServerError)
+	})
+
+	testServer := httptest.NewServer(mux)
+
+	tests := []struct {
+		name        string
+		downloadURL string
+		wantErr     bool
+	}{
+		{
+			name:        "Should succeed after two retries",
+			downloadURL: fmt.Sprintf("%s/succeeds-after-retry", testServer.URL),
+			wantErr:     false,
+		},
+		{
+			name:        "Should not retry forever",
+			downloadURL: fmt.Sprintf("%s/fails-forever", testServer.URL),
+			wantErr:     true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			retries = 0 // reset the retires
+			_, err := th.App.DownloadFromURL(tt.downloadURL)
+
+			if tt.wantErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}