use stderr instead and add tests

pkg/cmd/codespace/create.go

@@ -155,8 +155,9 @@ func (a *App) Create(ctx context.Context, opts createOptions) error {
 	cs := a.io.ColorScheme()
 
 	fmt.Fprintln(a.io.Out, codespace.Name)
-	if codespace.IdleTimeoutNotice != "" {
-		fmt.Fprintln(a.io.Out, cs.Cyan("Notice:"), codespace.IdleTimeoutNotice)
+
+	if a.io.IsStderrTTY() && codespace.IdleTimeoutNotice != "" {
+		fmt.Fprintln(a.io.ErrOut, cs.Yellow("Notice:"), codespace.IdleTimeoutNotice)
 	}
 
 	return nil

pkg/cmd/codespace/create_test.go

@@ -22,6 +22,7 @@ func TestApp_Create(t *testing.T) {
 		wantErr    error
 		wantStdout string
 		wantStderr string
+		isTTY      bool
 	}{
 		{
 			name: "create codespace with default branch and 30m idle timeout",
@@ -116,7 +117,59 @@ func TestApp_Create(t *testing.T) {
 				showStatus:  false,
 				idleTimeout: 30 * time.Minute,
 			},
-			wantStdout: "monalisa-dotfiles-abcd1234\nNotice: Idle timeout for this codespace is set to 10 minutes in compliance with your organization's policy\n",
+			wantStdout: "monalisa-dotfiles-abcd1234\n",
+			wantStderr: "Notice: Idle timeout for this codespace is set to 10 minutes in compliance with your organization's policy\n",
+			isTTY:      true,
+		},
+		{
+			name: "create codespace with default branch does not show idle timeout notice if not conntected to terminal",
+			fields: fields{
+				apiClient: &apiClientMock{
+					GetCodespaceRegionLocationFunc: func(ctx context.Context) (string, error) {
+						return "EUROPE", nil
+					},
+					GetRepositoryFunc: func(ctx context.Context, nwo string) (*api.Repository, error) {
+						return &api.Repository{
+							ID:            1234,
+							FullName:      nwo,
+							DefaultBranch: "main",
+						}, nil
+					},
+					GetCodespacesMachinesFunc: func(ctx context.Context, repoID int, branch, location string) ([]*api.Machine, error) {
+						return []*api.Machine{
+							{
+								Name:        "GIGA",
+								DisplayName: "Gigabits of a machine",
+							},
+						}, nil
+					},
+					CreateCodespaceFunc: func(ctx context.Context, params *api.CreateCodespaceParams) (*api.Codespace, error) {
+						if params.Branch != "main" {
+							return nil, fmt.Errorf("got branch %q, want %q", params.Branch, "main")
+						}
+						if params.IdleTimeoutMinutes != 30 {
+							return nil, fmt.Errorf("idle timeout minutes was %v", params.IdleTimeoutMinutes)
+						}
+						return &api.Codespace{
+							Name:              "monalisa-dotfiles-abcd1234",
+							IdleTimeoutNotice: "Idle timeout for this codespace is set to 10 minutes in compliance with your organization's policy",
+						}, nil
+					},
+					GetCodespaceRepoSuggestionsFunc: func(ctx context.Context, partialSearch string, params api.RepoSearchParameters) ([]string, error) {
+						return nil, nil // We can't ask for suggestions without a terminal.
+					},
+				},
+			},
+			opts: createOptions{
+				repo:        "monalisa/dotfiles",
+				branch:      "",
+				machine:     "GIGA",
+				showStatus:  false,
+				idleTimeout: 30 * time.Minute,
+			},
+			wantStdout: "monalisa-dotfiles-abcd1234\n",
+			wantStderr: "",
+			isTTY:      false,
 		},
 		{
 			name: "create codespace that requires accepting additional permissions",
@@ -173,6 +226,10 @@ Alternatively, you can run "create" with the "--default-permissions" option to c
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			io, _, stdout, stderr := iostreams.Test()
+			io.SetStdoutTTY(tt.isTTY)
+			io.SetStdinTTY(tt.isTTY)
+			io.SetStderrTTY(tt.isTTY)
+
 			a := &App{
 				io:        io,
 				apiClient: tt.fields.apiClient,