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package buffer
import "testing"
func TestNewBufferHoldsOneEmptyLine(t *testing.T) {
b := New()
if got := b.LineCount(); got != 1 {
t.Fatalf("LineCount() = %d, want 1", got)
}
if got := b.Line(0); got != "" {
t.Errorf("Line(0) = %q, want empty", got)
}
if b.Modified() {
t.Error("a fresh buffer must not be marked modified")
}
}
func TestNewFromStringSplitsOnLineFeeds(t *testing.T) {
b := NewFromString("package main\n\nfunc main() {}\n")
if got := b.LineCount(); got != 3 {
t.Fatalf("LineCount() = %d, want 3 (the trailing newline is not a line)", got)
}
for i, want := range []string{"package main", "", "func main() {}"} {
if got := b.Line(i); got != want {
t.Errorf("Line(%d) = %q, want %q", i, got, want)
}
}
if b.Modified() {
t.Error("loading text must not mark the buffer modified")
}
}
func TestTextRoundTripsTheTrailingNewline(t *testing.T) {
tests := []struct {
name string
text string
}{
{"with trailing newline", "a\nb\n"},
{"without trailing newline", "a\nb"},
{"empty", ""},
{"only a newline", "\n"},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
if got := NewFromString(tc.text).Text(); got != tc.text {
t.Errorf("Text() = %q, want %q", got, tc.text)
}
})
}
}
func TestTextPreservesWindowsLineEndings(t *testing.T) {
b := NewFromString("a\r\nb\r\n")
if got := b.LineCount(); got != 2 {
t.Fatalf("LineCount() = %d, want 2", got)
}
if got := b.Line(0); got != "a" {
t.Errorf("Line(0) = %q, want %q — the carriage return must be stripped", got, "a")
}
if got := b.Text(); got != "a\r\nb\r\n" {
t.Errorf("Text() = %q, want the original CRLF endings back", got)
}
}
func TestLineAccessorsToleratateOutOfRangeIndexes(t *testing.T) {
b := NewFromString("only")
for _, i := range []int{-1, 1, 99} {
if got := b.Line(i); got != "" {
t.Errorf("Line(%d) = %q, want empty", i, got)
}
if got := b.LineLen(i); got != 0 {
t.Errorf("LineLen(%d) = %d, want 0", i, got)
}
if got := b.LineRunes(i); got != nil {
t.Errorf("LineRunes(%d) = %v, want nil", i, got)
}
}
}
func TestLineRunesReturnsAnIndependentCopy(t *testing.T) {
b := NewFromString("abc")
runes := b.LineRunes(0)
runes[0] = 'X'
if got := b.Line(0); got != "abc" {
t.Errorf("Line(0) = %q after mutating the returned slice, want %q", got, "abc")
}
}
func TestSetTabWidthIgnoresNonPositiveValues(t *testing.T) {
b := New()
b.SetTabWidth(4)
if got := b.TabWidth(); got != 4 {
t.Fatalf("TabWidth() = %d, want 4", got)
}
b.SetTabWidth(0)
b.SetTabWidth(-2)
if got := b.TabWidth(); got != 4 {
t.Errorf("TabWidth() = %d, want the previous 4 to be kept", got)
}
}
func TestPositionOrdering(t *testing.T) {
first := Position{Line: 1, Col: 5}
sameLineLater := Position{Line: 1, Col: 6}
nextLine := Position{Line: 2, Col: 0}
if !first.Before(sameLineLater) {
t.Error("a smaller column on the same line must come first")
}
if !first.Before(nextLine) {
t.Error("a smaller line must come first whatever the columns")
}
if first.Before(first) {
t.Error("a position must not come before itself")
}
if !sameLineLater.After(first) {
t.Error("After must be the mirror of Before")
}
}
func TestNewRangeOrdersItsBounds(t *testing.T) {
low := Position{Line: 0, Col: 1}
high := Position{Line: 3, Col: 2}
if got := NewRange(high, low); got.Start != low || got.End != high {
t.Errorf("NewRange(high, low) = %+v, want the bounds swapped", got)
}
if got := NewRange(low, high); got.Start != low || got.End != high {
t.Errorf("NewRange(low, high) = %+v, want the bounds kept", got)
}
}
func TestRangeContainsExcludesItsEnd(t *testing.T) {
r := Range{Start: Position{Line: 1}, End: Position{Line: 1, Col: 3}}
if !r.Contains(Position{Line: 1}) {
t.Error("the start of a range is inside it")
}
if r.Contains(Position{Line: 1, Col: 3}) {
t.Error("the end of a range is outside it")
}
if empty := (Range{}); empty.Contains(Position{}) {
t.Error("an empty range contains nothing, not even its own position")
}
}
func TestAnEmptyBufferHoldsAnEmptyString(t *testing.T) {
// Not "\n": a buffer holds what was put into it, and nothing was.
if got := New().Text(); got != "" {
t.Errorf("New().Text() = %q, want empty", got)
}
if got := NewFromString("").Text(); got != "" {
t.Errorf("NewFromString(\"\").Text() = %q, want empty", got)
}
}
func TestPressingEnterGivesAFileItsTrailingNewline(t *testing.T) {
b := New()
b.Insert("package main")
b.InsertNewlineAndIndent()
if got := b.Text(); got != "package main\n" {
t.Errorf("Text() = %q, want %q", got, "package main\n")
}
}
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