feat: add motd-assist TUI for managing dynamic MOTDs

Initial Go project built with Bubble Tea and Lip Gloss:
- Live preview and management of /etc/update-motd.d scripts
- Embedded presets (ubuntu-default, minimal, server-dashboard)
- Bundled POSIX sh style scripts (brand header, sysinfo panel, footer)
- Snapshot/restore safety around applying changes
- CLI subcommands preview, apply, restore, list-presets
- Unit tests for detect, sanitize, and apply logic

internal/ui/model_test.go

@@ -0,0 +1,109 @@
+package ui
+
+import (
+	"strings"
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+
+	"motd-assist/internal/motd"
+	"motd-assist/internal/preset"
+)
+
+func mustUpdate(m Model, msg tea.Msg) Model {
+	next, _ := m.Update(msg)
+	return next.(Model)
+}
+
+func newTestModel(t *testing.T) Model {
+	t.Helper()
+	m := New(t.TempDir())
+	m = mustUpdate(m, tea.WindowSizeMsg{Width: 120, Height: 40})
+	return m
+}
+
+func TestViewRendersAllPanes(t *testing.T) {
+	m := newTestModel(t)
+	scripts := []motd.Script{
+		{Name: "00-header", Path: "/x/00-header", Enabled: true},
+		{Name: "10-sysinfo", Path: "/x/10-sysinfo", Enabled: false},
+	}
+	m = mustUpdate(m, discoverMsg{scripts: scripts, host: motd.HostInfo{Hostname: "myhost", Distro: "Ubuntu 24.04", PAM: true}})
+	m = mustUpdate(m, previewMsg{version: m.previewVersion, text: "Willkommen auf myhost"})
+
+	view := m.View()
+	for _, want := range []string{"Presets", "Scripte", "Live-Vorschau", "00-header", "10-sysinfo", "Willkommen auf myhost", "myhost"} {
+		if !strings.Contains(view, want) {
+			t.Errorf("View enthält %q nicht", want)
+		}
+	}
+}
+
+func TestToggleAndPlan(t *testing.T) {
+	m := newTestModel(t)
+	scripts := []motd.Script{
+		{Name: "00-header", Path: "/x/00-header", Enabled: true},
+		{Name: "10-sysinfo", Path: "/x/10-sysinfo", Enabled: false},
+	}
+	m = mustUpdate(m, discoverMsg{scripts: scripts})
+
+	// Fokus auf Scripte wechseln und erstes Script ausschalten.
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyTab})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeySpace})
+
+	plan := m.currentPlan()
+	if len(plan.Chmod) != 1 || plan.Chmod[0].Name != "00-header" || plan.Chmod[0].Enable {
+		t.Errorf("Chmod = %+v, want 00-header aus", plan.Chmod)
+	}
+	if markers := m.markersByRow(); markers["00-header"] != "aus" {
+		t.Errorf("Marker = %q, want aus", markers["00-header"])
+	}
+}
+
+func TestMoveRowChangesOrder(t *testing.T) {
+	m := newTestModel(t)
+	scripts := []motd.Script{
+		{Name: "00-header", Path: "/x", Enabled: true},
+		{Name: "10-sysinfo", Path: "/x", Enabled: true},
+	}
+	m = mustUpdate(m, discoverMsg{scripts: scripts})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyTab})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune("d")}) // nach unten
+
+	if m.working[0].Name != "10-sysinfo" || m.working[1].Name != "00-header" {
+		t.Errorf("Reihenfolge = %v, %v", m.working[0].Name, m.working[1].Name)
+	}
+	if plan := m.currentPlan(); len(plan.Renames) != 2 {
+		t.Errorf("Renames = %+v, want 2", plan.Renames)
+	}
+}
+
+func TestLoadPresetMarksPending(t *testing.T) {
+	m := newTestModel(t)
+	scripts := []motd.Script{{Name: "00-header", Path: "/x", Enabled: false}}
+	m = mustUpdate(m, discoverMsg{scripts: scripts})
+	m = mustUpdate(m, presetsMsg{presets: []preset.Preset{{Name: "p1", Scripts: []preset.Entry{{Name: "00-header", Enabled: true}}}}})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyEnter}) // erstes Preset laden
+
+	if plan := m.currentPlan(); len(plan.Chmod) != 1 || !plan.Chmod[0].Enable {
+		t.Errorf("Plan = %+v, want 00-header an", plan)
+	}
+	if m.status == "" {
+		t.Error("Statusmeldung nach Preset-Laden erwartet")
+	}
+}
+
+func TestDiscardResetsWorking(t *testing.T) {
+	m := newTestModel(t)
+	scripts := []motd.Script{{Name: "00-header", Path: "/x", Enabled: true}}
+	m = mustUpdate(m, discoverMsg{scripts: scripts})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyTab})
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeySpace}) // ausschalten
+	if m.currentPlan().Empty() {
+		t.Fatal("Plan sollte Änderungen haben")
+	}
+	m = mustUpdate(m, tea.KeyMsg{Type: tea.KeyEsc})
+	if !m.currentPlan().Empty() {
+		t.Errorf("nach esc sollte der Plan leer sein, ist %+v", m.currentPlan())
+	}
+}