diff --git a/go.mod b/go.mod
index 651ff78..0d1281f 100644
--- a/go.mod
+++ b/go.mod
@@ -9,9 +9,12 @@ require (
 
 require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/aymanbagabas/go-udiff v0.3.1 // indirect
 	github.com/charmbracelet/colorprofile v0.4.1 // indirect
 	github.com/charmbracelet/x/ansi v0.11.5 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.15 // indirect
+	github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a // indirect
+	github.com/charmbracelet/x/exp/teatest v0.0.0-20260209132835-6b065b8ba62c // indirect
 	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.9.0 // indirect
 	github.com/clipperhouse/stringish v0.1.1 // indirect
@@ -27,5 +30,5 @@ require (
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	golang.org/x/sys v0.38.0 // indirect
-	golang.org/x/text v0.3.8 // indirect
+	golang.org/x/text v0.28.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 3cb62b3..aace593 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/aymanbagabas/go-udiff v0.3.1 h1:LV+qyBQ2pqe0u42ZsUEtPiCaUoqgA9gYRDs3vj1nolY=
+github.com/aymanbagabas/go-udiff v0.3.1/go.mod h1:G0fsKmG+P6ylD0r6N/KgQD/nWzgfnl8ZBcNLgcbrw8E=
 github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
 github.com/charmbracelet/bubbletea v1.3.10/go.mod h1:ORQfo0fk8U+po9VaNvnV95UPWA1BitP1E0N6xJPlHr4=
 github.com/charmbracelet/colorprofile v0.4.1 h1:a1lO03qTrSIRaK8c3JRxJDZOvhvIeSco3ej+ngLk1kk=
@@ -10,6 +12,10 @@ github.com/charmbracelet/x/ansi v0.11.5 h1:NBWeBpj/lJPE3Q5l+Lusa4+mH6v7487OP8K0r
 github.com/charmbracelet/x/ansi v0.11.5/go.mod h1:2JNYLgQUsyqaiLovhU2Rv/pb8r6ydXKS3NIttu3VGZQ=
 github.com/charmbracelet/x/cellbuf v0.0.15 h1:ur3pZy0o6z/R7EylET877CBxaiE1Sp1GMxoFPAIztPI=
 github.com/charmbracelet/x/cellbuf v0.0.15/go.mod h1:J1YVbR7MUuEGIFPCaaZ96KDl5NoS0DAWkskup+mOY+Q=
+github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a h1:G99klV19u0QnhiizODirwVksQB91TJKV/UaTnACcG30=
+github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
+github.com/charmbracelet/x/exp/teatest v0.0.0-20260209132835-6b065b8ba62c h1:uX4zKWQHqiMBzPo1Lwh+xMeU3qDm9Tw5yX/AXVQZGNo=
+github.com/charmbracelet/x/exp/teatest v0.0.0-20260209132835-6b065b8ba62c/go.mod h1:aPVjFrBwbJgj5Qz1F0IXsnbcOVJcMKgu1ySUfTAxh7k=
 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/clipperhouse/displaywidth v0.9.0 h1:Qb4KOhYwRiN3viMv1v/3cTBlz3AcAZX3+y9OLhMtAtA=
@@ -46,3 +52,5 @@ golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
+golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
+golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
diff --git a/main.go b/main.go
index de2a58c..1cd8490 100644
--- a/main.go
+++ b/main.go
@@ -3,8 +3,9 @@ package main
 import tea "github.com/charmbracelet/bubbletea"
 
 func main() {
+	lines := []string{"Hello world", "line 2", "line 3", "line 4", "line 5"}
 	tea.NewProgram(
-		newModel(),
+		newModel(lines),
 		tea.WithAltScreen(),
 	).Run()
 }
diff --git a/model.go b/model.go
index 9f30e27..462dd3b 100644
--- a/model.go
+++ b/model.go
@@ -31,16 +31,9 @@ type model struct {
 	insertAction Action
 }
 
-func newModel() model {
+func newModel(lines []string) model {
 	return model{
-		lines: []string{
-			"Hello world",
-			"line 2",
-			"line 3",
-			"line 4",
-			"line 5",
-			"line 6",
-		},
+		lines: lines,
 		cursor: cursor{
 			x: 0,
 			y: 0,
@@ -52,6 +45,20 @@ func newModel() model {
 	}
 }
 
+func newModelWithPos(lines []string, pos Position) model {
+	return model{
+		lines: lines,
+		cursor: cursor{
+			x: pos.Col,
+			y: pos.Line,
+		},
+		s_gutter: 5,
+		mode:     NormalMode,
+		command:  "",
+		input:    NewInputHandler(),
+	}
+}
+
 func (m model) Init() tea.Cmd {
 	return nil
 }
diff --git a/motion_test.go b/motion_test.go
new file mode 100644
index 0000000..3e20224
--- /dev/null
+++ b/motion_test.go
@@ -0,0 +1,325 @@
+package main
+
+import (
+	"testing"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/x/exp/teatest"
+)
+
+// sendKeys sends a sequence of keys to the test model
+func sendKeys(tm *teatest.TestModel, keys ...string) {
+	for _, key := range keys {
+		switch key {
+		case "esc":
+			tm.Send(tea.KeyMsg{Type: tea.KeyEscape})
+		case "enter":
+			tm.Send(tea.KeyMsg{Type: tea.KeyEnter})
+		case "backspace":
+			tm.Send(tea.KeyMsg{Type: tea.KeyBackspace})
+		case "ctrl+c":
+			tm.Send(tea.KeyMsg{Type: tea.KeyCtrlC})
+		case "ctrl+d":
+			tm.Send(tea.KeyMsg{Type: tea.KeyCtrlD})
+		default:
+			tm.Send(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(key)})
+		}
+	}
+}
+
+// newTestModel creates a test model with default content
+func newTestModel(t *testing.T) *teatest.TestModel {
+	lines := []string{"line 1", "line 2", "line 3", "line 4", "line 5", "line 6"}
+	return teatest.NewTestModel(t, newModel(lines), teatest.WithInitialTermSize(80, 24))
+}
+
+func newTestModelWithLines(t *testing.T, lines []string) *teatest.TestModel {
+	return teatest.NewTestModel(t, newModel(lines), teatest.WithInitialTermSize(80, 24))
+}
+
+func newTestModelWithCursorPos(t *testing.T, pos Position) *teatest.TestModel {
+	lines := []string{"line 1", "line 2", "line 3", "line 4", "line 5", "line 6"}
+	return teatest.NewTestModel(t, newModelWithPos(lines, pos), teatest.WithInitialTermSize(80, 24))
+}
+
+func newTestModelWithCursorPosAndLines(t *testing.T, lines []string, pos Position) *teatest.TestModel {
+	return teatest.NewTestModel(t, newModelWithPos(lines, pos), teatest.WithInitialTermSize(80, 24))
+}
+
+// getFinalModel extracts the final model state (sends ctrl+c to quit first)
+func getFinalModel(t *testing.T, tm *teatest.TestModel) model {
+	tm.Send(tea.KeyMsg{Type: tea.KeyCtrlC})
+	fm := tm.FinalModel(t, teatest.WithFinalTimeout(time.Second))
+	return fm.(model)
+}
+
+func TestMoveDown(t *testing.T) {
+	t.Run("test 'j'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 1 {
+			t.Errorf("cursor.y = %d, want 1", m.cursor.y)
+		}
+	})
+
+	t.Run("test 'jjjj'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "j", "j", "j", "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 4 {
+			t.Errorf("cursor.y = %d, want 4", m.cursor.y)
+		}
+	})
+
+	t.Run("test 'jjjjjjjjj's with overflow", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "j", "j", "j", "j", "j", "j", "j", "j", "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 5 {
+			t.Errorf("cursor.y = %d, want 5", m.cursor.y)
+		}
+	})
+}
+
+func TestMoveDownWithCount(t *testing.T) {
+	t.Run("test '3j'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "3", "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 3 {
+			t.Errorf("cursor.y = %d, want 3", m.cursor.y)
+		}
+	})
+
+	t.Run("test '10j' with overflow", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "1", "0", "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 5 {
+			t.Errorf("cursor.y = %d, want 5", m.cursor.y)
+		}
+	})
+}
+
+func TestMoveDownWithOverflow(t *testing.T) {
+	lines := []string{"long line", "small"}
+
+	t.Run("test 'j' with overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPosAndLines(t, lines, Position{Col: 8, Line: 0})
+		sendKeys(tm, "j")
+
+		m := getFinalModel(t, tm)
+		want := len(lines[1])
+		if m.cursor.x != want {
+			t.Errorf("cursor.x = %d, want %d", m.cursor.x, want)
+		}
+	})
+
+	t.Run("test 'j' without overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPosAndLines(t, lines, Position{Col: 3, Line: 0})
+		sendKeys(tm, "j")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 3 {
+			t.Errorf("cursor.x = %d, want 3", m.cursor.x)
+		}
+	})
+}
+
+func TestMoveUp(t *testing.T) {
+	t.Run("test 'k'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 0, Line: 2})
+		sendKeys(tm, "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 1 {
+			t.Errorf("cursor.y = %d, want 1", m.cursor.y)
+		}
+	})
+
+	t.Run("test 'kkkk'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 0, Line: 4})
+		sendKeys(tm, "k", "k", "k", "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 0 {
+			t.Errorf("cursor.y = %d, want 0", m.cursor.y)
+		}
+	})
+
+	t.Run("test 'k' at top (no movement)", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "k", "k", "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 0 {
+			t.Errorf("cursor.y = %d, want 0", m.cursor.y)
+		}
+	})
+}
+
+func TestMoveUpWithCount(t *testing.T) {
+	t.Run("test '3k'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 0, Line: 5})
+		sendKeys(tm, "3", "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 2 {
+			t.Errorf("cursor.y = %d, want 2", m.cursor.y)
+		}
+	})
+
+	t.Run("test '10k' with overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 0, Line: 3})
+		sendKeys(tm, "1", "0", "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.y != 0 {
+			t.Errorf("cursor.y = %d, want 0", m.cursor.y)
+		}
+	})
+}
+
+func TestMoveUpWithOverflow(t *testing.T) {
+	lines := []string{"small", "long line"}
+
+	t.Run("test 'k' with overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPosAndLines(t, lines, Position{Col: 10, Line: 1})
+		sendKeys(tm, "k")
+
+		m := getFinalModel(t, tm)
+		want := len(lines[0])
+		if m.cursor.x != want {
+			t.Errorf("cursor.x = %d, want %d", m.cursor.x, want)
+		}
+	})
+
+	t.Run("test 'k' without overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPosAndLines(t, lines, Position{Col: 3, Line: 1})
+		sendKeys(tm, "k")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 3 {
+			t.Errorf("cursor.x = %d, want 3", m.cursor.x)
+		}
+	})
+}
+
+func TestMoveRight(t *testing.T) {
+	t.Run("test 'l'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "l")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 1 {
+			t.Errorf("cursor.x = %d, want 1", m.cursor.x)
+		}
+	})
+
+	t.Run("test 'llll'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "l", "l", "l", "l")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 4 {
+			t.Errorf("cursor.x = %d, want 4", m.cursor.x)
+		}
+	})
+
+	t.Run("test 'l' at end of line (no movement past end)", func(t *testing.T) {
+		lines := []string{"abc"}
+		tm := newTestModelWithLines(t, lines)
+		sendKeys(tm, "l", "l", "l", "l", "l", "l")
+
+		m := getFinalModel(t, tm)
+		want := len(lines[0])
+		if m.cursor.x != want {
+			t.Errorf("cursor.x = %d, want %d", m.cursor.x, want)
+		}
+	})
+}
+
+func TestMoveRightWithCount(t *testing.T) {
+	t.Run("test '3l'", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "3", "l")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 3 {
+			t.Errorf("cursor.x = %d, want 3", m.cursor.x)
+		}
+	})
+
+	t.Run("test '10l' with overflow", func(t *testing.T) {
+		lines := []string{"short"}
+		tm := newTestModelWithLines(t, lines)
+		sendKeys(tm, "1", "0", "l")
+
+		m := getFinalModel(t, tm)
+		want := len(lines[0])
+		if m.cursor.x != want {
+			t.Errorf("cursor.x = %d, want %d", m.cursor.x, want)
+		}
+	})
+}
+
+func TestMoveLeft(t *testing.T) {
+	t.Run("test 'h'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 3, Line: 0})
+		sendKeys(tm, "h")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 2 {
+			t.Errorf("cursor.x = %d, want 2", m.cursor.x)
+		}
+	})
+
+	t.Run("test 'hhhh'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 4, Line: 0})
+		sendKeys(tm, "h", "h", "h", "h")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 0 {
+			t.Errorf("cursor.x = %d, want 0", m.cursor.x)
+		}
+	})
+
+	t.Run("test 'h' at start (no movement)", func(t *testing.T) {
+		tm := newTestModel(t)
+		sendKeys(tm, "h", "h", "h")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 0 {
+			t.Errorf("cursor.x = %d, want 0", m.cursor.x)
+		}
+	})
+}
+
+func TestMoveLeftWithCount(t *testing.T) {
+	t.Run("test '3h'", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 5, Line: 0})
+		sendKeys(tm, "3", "h")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 2 {
+			t.Errorf("cursor.x = %d, want 2", m.cursor.x)
+		}
+	})
+
+	t.Run("test '10h' with overflow", func(t *testing.T) {
+		tm := newTestModelWithCursorPos(t, Position{Col: 3, Line: 0})
+		sendKeys(tm, "1", "0", "h")
+
+		m := getFinalModel(t, tm)
+		if m.cursor.x != 0 {
+			t.Errorf("cursor.x = %d, want 0", m.cursor.x)
+		}
+	})
+}