From 2a86751df9eb4a09af81bf3bdc6c163664b14914 Mon Sep 17 00:00:00 2001
From: Anna Rose Wiggins <annabunches@gmail.com>
Date: Thu, 17 Jul 2025 20:23:26 -0400
Subject: [PATCH] Add tests for EventBuffer.

---
 cmd/joyful/main.go                         |  2 +-
 internal/virtualdevice/eventbuffer.go      | 27 +++++--
 internal/virtualdevice/eventbuffer_test.go | 88 ++++++++++++++++++++++
 internal/virtualdevice/interfaces.go       |  7 ++
 4 files changed, 116 insertions(+), 8 deletions(-)
 create mode 100644 internal/virtualdevice/eventbuffer_test.go
 create mode 100644 internal/virtualdevice/interfaces.go

diff --git a/cmd/joyful/main.go b/cmd/joyful/main.go
index e504372..7e5a807 100644
--- a/cmd/joyful/main.go
+++ b/cmd/joyful/main.go
@@ -41,7 +41,7 @@ func initVirtualBuffers(config *config.ConfigParser) (map[string]*virtualdevice.
 func getVirtualDevices(buffers map[string]*virtualdevice.EventBuffer) map[string]*evdev.InputDevice {
 	devices := make(map[string]*evdev.InputDevice)
 	for name, buffer := range buffers {
-		devices[name] = buffer.Device
+		devices[name] = buffer.Device.(*evdev.InputDevice)
 	}
 	return devices
 }
diff --git a/internal/virtualdevice/eventbuffer.go b/internal/virtualdevice/eventbuffer.go
index e95c099..9a46341 100644
--- a/internal/virtualdevice/eventbuffer.go
+++ b/internal/virtualdevice/eventbuffer.go
@@ -10,12 +10,12 @@ import (
 
 type EventBuffer struct {
 	events []*evdev.InputEvent
-	Device *evdev.InputDevice
+	Device VirtualDevice
 }
 
-func NewEventBuffer(device *evdev.InputDevice) *EventBuffer {
+func NewEventBuffer(device VirtualDevice) *EventBuffer {
 	return &EventBuffer{
-		events: make([]*evdev.InputEvent, 0),
+		events: make([]*evdev.InputEvent, 0, 100),
 		Device: device,
 	}
 }
@@ -24,20 +24,33 @@ func (buffer *EventBuffer) AddEvent(event *evdev.InputEvent) {
 	buffer.events = append(buffer.events, event)
 }
 
-func (buffer *EventBuffer) SendEvents() {
+func (buffer *EventBuffer) SendEvents() []error {
 	eventTime := syscall.NsecToTimeval(int64(time.Now().Nanosecond()))
+	writeErrors := make([]error, 0)
+
+	if len(buffer.events) == 0 {
+		return writeErrors
+	}
 
 	for i := 0; i < len(buffer.events); i++ {
 		buffer.events[i].Time = eventTime
-		buffer.Device.WriteOne(buffer.events[i])
+		err := buffer.Device.WriteOne(buffer.events[i])
+		if err != nil {
+			writeErrors = append(writeErrors, err)
+		}
 	}
 
-	buffer.Device.WriteOne(&evdev.InputEvent{
+	err := buffer.Device.WriteOne(&evdev.InputEvent{
 		Time:  eventTime,
 		Type:  evdev.EV_SYN,
 		Code:  evdev.SYN_REPORT,
 		Value: 0,
 	})
 
-	buffer.events = make([]*evdev.InputEvent, 0)
+	if err != nil {
+		writeErrors = append(writeErrors, err)
+	}
+
+	buffer.events = make([]*evdev.InputEvent, 0, 100)
+	return writeErrors
 }
diff --git a/internal/virtualdevice/eventbuffer_test.go b/internal/virtualdevice/eventbuffer_test.go
new file mode 100644
index 0000000..515de5f
--- /dev/null
+++ b/internal/virtualdevice/eventbuffer_test.go
@@ -0,0 +1,88 @@
+package virtualdevice
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/holoplot/go-evdev"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+)
+
+type EventBufferTests struct {
+	suite.Suite
+	device       *VirtualDeviceMock
+	writeOneCall *mock.Call
+}
+
+type VirtualDeviceMock struct {
+	mock.Mock
+}
+
+func (m *VirtualDeviceMock) WriteOne(event *evdev.InputEvent) error {
+	args := m.Called()
+	return args.Error(0)
+}
+
+func TestRunnerEventBufferTests(t *testing.T) {
+	suite.Run(t, new(EventBufferTests))
+}
+
+func (t *EventBufferTests) SetupTest() {
+	t.device = new(VirtualDeviceMock)
+}
+
+func (t *EventBufferTests) SetupSubTest() {
+	t.device = new(VirtualDeviceMock)
+	t.writeOneCall = t.device.On("WriteOne").Return(nil)
+}
+
+func (t *EventBufferTests) TearDownSubTest() {
+	t.writeOneCall.Unset()
+}
+
+func (t *EventBufferTests) TestNewEventBuffer() {
+	buffer := NewEventBuffer(t.device)
+	t.Equal(t.device, buffer.Device)
+	t.Len(buffer.events, 0)
+}
+
+func (t *EventBufferTests) TestEventBufferAddEvent() {
+	buffer := NewEventBuffer(t.device)
+	buffer.AddEvent(&evdev.InputEvent{})
+	buffer.AddEvent(&evdev.InputEvent{})
+	buffer.AddEvent(&evdev.InputEvent{})
+	t.Len(buffer.events, 3)
+}
+
+func (t *EventBufferTests) TestEventBufferSendEvents() {
+	t.Run("3 Events", func() {
+		buffer := NewEventBuffer(t.device)
+		buffer.AddEvent(&evdev.InputEvent{})
+		buffer.AddEvent(&evdev.InputEvent{})
+		buffer.AddEvent(&evdev.InputEvent{})
+		errs := buffer.SendEvents()
+
+		t.Len(errs, 0)
+		t.device.AssertNumberOfCalls(t.T(), "WriteOne", 4)
+	})
+
+	t.Run("No Events", func() {
+		buffer := NewEventBuffer(t.device)
+		errs := buffer.SendEvents()
+
+		t.Len(errs, 0)
+		t.device.AssertNumberOfCalls(t.T(), "WriteOne", 0)
+	})
+
+	t.Run("Bad Event", func() {
+		t.writeOneCall.Unset()
+		t.writeOneCall = t.device.On("WriteOne").Return(errors.New("Fail"))
+
+		buffer := NewEventBuffer(t.device)
+		buffer.AddEvent(&evdev.InputEvent{})
+		errs := buffer.SendEvents()
+		t.Len(errs, 2)
+	})
+
+}
diff --git a/internal/virtualdevice/interfaces.go b/internal/virtualdevice/interfaces.go
new file mode 100644
index 0000000..561c1bc
--- /dev/null
+++ b/internal/virtualdevice/interfaces.go
@@ -0,0 +1,7 @@
+package virtualdevice
+
+import "github.com/holoplot/go-evdev"
+
+type VirtualDevice interface {
+	WriteOne(*evdev.InputEvent) error
+}