Change project layout and use go.mod

internal/buffer/stack_test.go

@@ -0,0 +1,35 @@
+package buffer
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStack(t *testing.T) {
+	s := new(TEStack)
+	e1 := &TextEvent{
+		EventType: TextEventReplace,
+		Time:      time.Now(),
+	}
+	e2 := &TextEvent{
+		EventType: TextEventInsert,
+		Time:      time.Now(),
+	}
+	s.Push(e1)
+	s.Push(e2)
+
+	p := s.Peek()
+	assert.Equal(t, p.EventType, TextEventInsert)
+	p = s.Pop()
+	assert.Equal(t, p.EventType, TextEventInsert)
+	p = s.Peek()
+	assert.Equal(t, p.EventType, TextEventReplace)
+	p = s.Pop()
+	assert.Equal(t, p.EventType, TextEventReplace)
+	p = s.Pop()
+	assert.Nil(t, p)
+	p = s.Peek()
+	assert.Nil(t, p)
+}