test: add teatest-based Spawn coverage and WindowSizeMsg test

Extract runProgram function variable from Spawn (matching existing
testability pattern) and use teatest/v2 to exercise Spawn through a
real Bubbletea program lifecycle. Adds WindowSizeMsg handler coverage.

Author: ncode

go.mod

@@ -16,9 +16,12 @@ require (
 require (
 	charm.land/lipgloss/v2 v2.0.2 // indirect
 	github.com/atotto/clipboard v0.1.4 // indirect
+	github.com/aymanbagabas/go-udiff v0.4.1 // indirect
 	github.com/charmbracelet/colorprofile v0.4.2 // indirect
 	github.com/charmbracelet/ultraviolet v0.0.0-20260205113103-524a6607adb8 // indirect
 	github.com/charmbracelet/x/ansi v0.11.6 // indirect
+	github.com/charmbracelet/x/exp/golden v0.0.0-20251109135125-8916d276318f // indirect
+	github.com/charmbracelet/x/exp/teatest/v2 v2.0.0-20260323091123-df7b1bcffcca // indirect
 	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/charmbracelet/x/termios v0.1.1 // indirect
 	github.com/charmbracelet/x/windows v0.2.2 // indirect

go.sum

@@ -16,6 +16,10 @@ github.com/charmbracelet/x/ansi v0.11.6 h1:GhV21SiDz/45W9AnV2R61xZMRri5NlLnl6CVF
 github.com/charmbracelet/x/ansi v0.11.6/go.mod h1:2JNYLgQUsyqaiLovhU2Rv/pb8r6ydXKS3NIttu3VGZQ=
 github.com/charmbracelet/x/exp/golden v0.0.0-20250806222409-83e3a29d542f h1:pk6gmGpCE7F3FcjaOEKYriCvpmIN4+6OS/RD0vm4uIA=
 github.com/charmbracelet/x/exp/golden v0.0.0-20250806222409-83e3a29d542f/go.mod h1:IfZAMTHB6XkZSeXUqriemErjAWCCzT0LwjKFYCZyw0I=
+github.com/charmbracelet/x/exp/golden v0.0.0-20251109135125-8916d276318f h1:8CnFOYzrMArVN42jYaGvnBo3mxdONgt09fly+9B96GY=
+github.com/charmbracelet/x/exp/golden v0.0.0-20251109135125-8916d276318f/go.mod h1:V8n/g3qVKNxr2FR37Y+otCsMySvZr601T0C7coEP0bw=
+github.com/charmbracelet/x/exp/teatest/v2 v2.0.0-20260323091123-df7b1bcffcca h1:Tl5ey00ZDMTGQ3ZWAJAADx2/OxNgN0LFTxmwPKvq04A=
+github.com/charmbracelet/x/exp/teatest/v2 v2.0.0-20260323091123-df7b1bcffcca/go.mod h1:aRoQwQWmN9LBG2xi3sVByMFt2fdkPCagd0GAJ1qwOfw=
 github.com/charmbracelet/x/term v0.2.2 h1:xVRT/S2ZcKdhhOuSP4t5cLi5o+JxklsoEObBSgfgZRk=
 github.com/charmbracelet/x/term v0.2.2/go.mod h1:kF8CY5RddLWrsgVwpw4kAa6TESp6EB5y3uxGLeCqzAI=
 github.com/charmbracelet/x/termios v0.1.1 h1:o3Q2bT8eqzGnGPOYheoYS8eEleT5ZVNYNy8JawjaNZY=

internal/shell/shell.go

@@ -18,6 +18,10 @@ func outputBufferSize(hostCount int) int {
 	return size
 }
 
+var runProgram = func(m tea.Model) (tea.Model, error) {
+	return tea.NewProgram(m).Run()
+}
+
 func Spawn(hostList *sshConn.HostList) {
 	broker := make(chan sshConn.CommandRequest)
 	hostCount := 0
@@ -27,8 +31,7 @@ func Spawn(hostList *sshConn.HostList) {
 	events := make(chan sshConn.OutputEvent, outputBufferSize(hostCount))
 	go sshConn.Broker(hostList, broker, events)
 
-	p := tea.NewProgram(initialModel(hostList, broker, events))
-	if _, err := p.Run(); err != nil {
+	if _, err := runProgram(initialModel(hostList, broker, events)); err != nil {
 		panic(err)
 	}
 }

internal/shell/shell_test.go

@@ -1,6 +1,13 @@
 package shell
 
-import "testing"
+import (
+	"testing"
+	"time"
+
+	tea "charm.land/bubbletea/v2"
+	teatest "github.com/charmbracelet/x/exp/teatest/v2"
+	"github.com/ncode/pretty/internal/sshConn"
+)
 
 func TestOutputBufferSizeMinimum(t *testing.T) {
 	if got := outputBufferSize(0); got != 128 {
@@ -13,3 +20,27 @@ func TestOutputBufferSizeScales(t *testing.T) {
 		t.Fatalf("unexpected size: %d", got)
 	}
 }
+
+func TestSpawnExitsOnBye(t *testing.T) {
+	orig := runProgram
+	t.Cleanup(func() { runProgram = orig })
+
+	var final tea.Model
+	runProgram = func(m tea.Model) (tea.Model, error) {
+		tm := teatest.NewTestModel(t, m, teatest.WithInitialTermSize(80, 24))
+		tm.Type(":bye")
+		tm.Send(tea.KeyPressMsg{Code: tea.KeyEnter})
+		final = tm.FinalModel(t, teatest.WithFinalTimeout(5*time.Second))
+		return final, nil
+	}
+
+	Spawn(sshConn.NewHostList())
+
+	m, ok := final.(model)
+	if !ok {
+		t.Fatalf("expected model, got %T", final)
+	}
+	if !m.quit {
+		t.Fatal("expected model to be in quit state")
+	}
+}