1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
|
package terminal
import (
"strings"
"testing"
"github.com/gdamore/tcell/v2"
)
// writeString puts a run of characters onto a screen, as a program would.
func writeString(s *Screen, text string) {
for _, r := range text {
s.WriteRune(r)
}
}
// wantLines fails the test unless the screen's rows read as expected. Rows
// beyond the ones given are not checked.
func wantLines(t *testing.T, s *Screen, lines ...string) {
t.Helper()
for row, want := range lines {
if got := s.LineText(row); got != want {
t.Errorf("row %d = %q, want %q", row, got, want)
}
}
}
func TestANewScreenIsBlankWithTheCursorAtTheTopLeft(t *testing.T) {
s := NewScreen(20, 5)
width, height := s.Size()
if width != 20 || height != 5 {
t.Errorf("Size() = %dx%d, want 20x5", width, height)
}
if got := s.Cursor(); got != (Cursor{}) {
t.Errorf("Cursor() = %+v, want the top left", got)
}
if !s.CursorVisible() {
t.Error("CursorVisible() = false on a new screen")
}
for row := range 5 {
if got := s.LineText(row); got != "" {
t.Errorf("row %d = %q, want it blank", row, got)
}
}
}
func TestASizeBelowOneIsRaisedToOne(t *testing.T) {
s := NewScreen(0, -3)
if width, height := s.Size(); width != 1 || height != 1 {
t.Errorf("Size() = %dx%d, want 1x1 — the cursor must have somewhere to be", width, height)
}
s.WriteRune('x') // must not panic
}
func TestWritingAdvancesTheCursor(t *testing.T) {
s := NewScreen(20, 3)
writeString(s, "hello")
wantLines(t, s, "hello")
if got := s.Cursor(); got != (Cursor{Row: 0, Col: 5}) {
t.Errorf("Cursor() = %+v, want column 5", got)
}
}
func TestTheCursorStopsInTheLastColumnUntilTheNextCharacter(t *testing.T) {
// A character written in the last column must not scroll the screen by
// itself. Only the character after it wraps.
s := NewScreen(3, 2)
writeString(s, "abc")
if got := s.Cursor(); got != (Cursor{Row: 0, Col: 2}) {
t.Fatalf("Cursor() = %+v, want it parked in the last column", got)
}
wantLines(t, s, "abc", "")
s.WriteRune('d')
wantLines(t, s, "abc", "d")
}
func TestWrappingCanBeTurnedOff(t *testing.T) {
s := NewScreen(3, 2)
s.SetAutoWrap(false)
writeString(s, "abcdef")
wantLines(t, s, "abf", "")
if got := s.Cursor(); got != (Cursor{Row: 0, Col: 2}) {
t.Errorf("Cursor() = %+v, want it held in the last column", got)
}
}
func TestMoveToClampsToTheScreen(t *testing.T) {
s := NewScreen(10, 4)
tests := []struct {
name string
row, col int
want Cursor
}{
{"inside", 2, 3, Cursor{Row: 2, Col: 3}},
{"past the bottom", 99, 0, Cursor{Row: 3, Col: 0}},
{"past the right", 0, 99, Cursor{Row: 0, Col: 9}},
{"negative", -5, -5, Cursor{}},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
s.MoveTo(tc.row, tc.col)
if got := s.Cursor(); got != tc.want {
t.Errorf("MoveTo(%d, %d) gave %+v, want %+v", tc.row, tc.col, got, tc.want)
}
})
}
}
func TestCarriageReturnAndLineFeed(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "one")
s.CarriageReturn()
if got := s.Cursor().Col; got != 0 {
t.Errorf("after a carriage return the cursor is at column %d, want 0", got)
}
s.LineFeed()
if got := s.Cursor(); got != (Cursor{Row: 1, Col: 0}) {
t.Errorf("Cursor() = %+v, want the start of the next line", got)
}
}
func TestALineFeedOnTheLastRowScrolls(t *testing.T) {
s := NewScreen(10, 3)
for _, text := range []string{"one", "two", "three"} {
writeString(s, text)
s.CarriageReturn()
s.LineFeed()
}
wantLines(t, s, "two", "three", "")
if got := s.ScrollbackLen(); got != 1 {
t.Errorf("ScrollbackLen() = %d, want the scrolled-off line kept", got)
}
}
func TestReverseLineFeedScrollsDownAtTheTop(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "one")
s.MoveTo(0, 0)
s.ReverseLineFeed()
wantLines(t, s, "", "one")
if got := s.Cursor().Row; got != 0 {
t.Errorf("Cursor().Row = %d, want it held at the top", got)
}
}
func TestBackspaceMovesWithoutErasing(t *testing.T) {
s := NewScreen(10, 2)
writeString(s, "abc")
s.Backspace()
if got := s.Cursor().Col; got != 2 {
t.Errorf("Cursor().Col = %d, want 2", got)
}
wantLines(t, s, "abc")
s.MoveTo(0, 0)
s.Backspace()
if got := s.Cursor().Col; got != 0 {
t.Errorf("Cursor().Col = %d, want it held at the first column", got)
}
}
func TestTabMovesToTheNextStop(t *testing.T) {
s := NewScreen(30, 2)
s.Tab()
if got := s.Cursor().Col; got != TabWidth {
t.Errorf("Cursor().Col = %d, want %d", got, TabWidth)
}
s.MoveTo(0, 3)
s.Tab()
if got := s.Cursor().Col; got != TabWidth {
t.Errorf("Cursor().Col = %d, want the next stop at %d", got, TabWidth)
}
}
func TestTabStopsAtTheLastColumn(t *testing.T) {
s := NewScreen(10, 2)
s.MoveTo(0, 9)
s.Tab()
if got := s.Cursor().Col; got != 9 {
t.Errorf("Cursor().Col = %d, want it held in the last column", got)
}
}
func TestSaveAndRestoreCursorCarryTheStyle(t *testing.T) {
s := NewScreen(10, 4)
s.MoveTo(2, 3)
s.SetStyle(tcell.StyleDefault.Bold(true))
s.SaveCursor()
s.MoveTo(0, 0)
s.SetStyle(tcell.StyleDefault)
s.RestoreCursor()
if got := s.Cursor(); got != (Cursor{Row: 2, Col: 3}) {
t.Errorf("Cursor() = %+v, want what was saved", got)
}
if _, _, attrs := s.Style().Decompose(); attrs&tcell.AttrBold == 0 {
t.Error("the saved style was not restored")
}
}
func TestEraseDisplay(t *testing.T) {
fill := func() *Screen {
s := NewScreen(5, 3)
for row, text := range []string{"aaaaa", "bbbbb", "ccccc"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.MoveTo(1, 2)
return s
}
tests := []struct {
name string
mode EraseMode
lines []string
}{
{"to the end", EraseToEnd, []string{"aaaaa", "bb", ""}},
{"to the start", EraseToStart, []string{"", " bb", "ccccc"}},
{"all of it", EraseAll, []string{"", "", ""}},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
s := fill()
s.EraseDisplay(tc.mode)
wantLines(t, s, tc.lines...)
if got := s.Cursor(); got != (Cursor{Row: 1, Col: 2}) {
t.Errorf("Cursor() = %+v, want it left where it was", got)
}
})
}
}
func TestEraseLine(t *testing.T) {
tests := []struct {
name string
mode EraseMode
want string
}{
{"to the end", EraseToEnd, "ab"},
{"to the start", EraseToStart, " de"},
{"all of it", EraseAll, ""},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
s := NewScreen(5, 2)
writeString(s, "abcde")
s.MoveTo(0, 2)
s.EraseLine(tc.mode)
wantLines(t, s, tc.want)
})
}
}
func TestEraseCharsBlanksInPlace(t *testing.T) {
s := NewScreen(6, 2)
writeString(s, "abcdef")
s.MoveTo(0, 1)
s.EraseChars(3)
wantLines(t, s, "a ef")
}
func TestInsertAndDeleteChars(t *testing.T) {
s := NewScreen(6, 2)
writeString(s, "abcdef")
s.MoveTo(0, 2)
s.DeleteChars(2)
wantLines(t, s, "abef")
s.MoveTo(0, 2)
s.InsertChars(2)
wantLines(t, s, "ab ef")
}
func TestInsertAndDeleteCharsAreClampedToTheLine(t *testing.T) {
s := NewScreen(4, 2)
writeString(s, "abcd")
s.MoveTo(0, 2)
s.DeleteChars(99) // must not read past the line
wantLines(t, s, "ab")
s.InsertChars(99)
wantLines(t, s, "ab")
}
func TestInsertAndDeleteLines(t *testing.T) {
build := func() *Screen {
s := NewScreen(5, 4)
for row, text := range []string{"one", "two", "three", "four"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.MoveTo(1, 0)
return s
}
s := build()
s.InsertLines(1)
wantLines(t, s, "one", "", "two", "three")
s = build()
s.DeleteLines(1)
wantLines(t, s, "one", "three", "four", "")
}
func TestInsertLinesOutsideTheScrollRegionDoesNothing(t *testing.T) {
// A program with a status line on row 0 narrows the region so that its
// status line stays put; an insert from outside must not push it about.
s := NewScreen(5, 4)
s.MoveTo(0, 0)
writeString(s, "stay")
s.SetScrollRegion(1, 3)
s.MoveTo(0, 0)
s.InsertLines(2)
wantLines(t, s, "stay")
}
func TestTheScrollRegionLimitsScrolling(t *testing.T) {
s := NewScreen(5, 4)
for row, text := range []string{"head", "a", "b", "c"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.SetScrollRegion(1, 3)
s.MoveTo(3, 0)
s.LineFeed()
wantLines(t, s, "head", "b", "c", "")
}
func TestSettingTheScrollRegionMovesTheCursorHome(t *testing.T) {
s := NewScreen(5, 4)
s.MoveTo(3, 3)
s.SetScrollRegion(1, 3)
if got := s.Cursor(); got != (Cursor{}) {
t.Errorf("Cursor() = %+v, want the top left", got)
}
}
func TestAnImpossibleScrollRegionIsIgnored(t *testing.T) {
s := NewScreen(5, 4)
s.SetScrollRegion(1, 3)
s.MoveTo(2, 2)
s.SetScrollRegion(3, 1) // the wrong way round
s.SetScrollRegion(2, 2) // empty
s.MoveTo(3, 0)
s.LineFeed()
if got := s.Cursor().Row; got != 3 {
t.Errorf("Cursor().Row = %d, want the earlier region still in force", got)
}
}
func TestScrollingANarrowRegionIsNotHistory(t *testing.T) {
// Lines leaving a narrow region are part of a program redrawing its own
// display, not lines the session has finished with.
s := NewScreen(5, 4)
s.SetScrollRegion(1, 3)
s.MoveTo(3, 0)
s.LineFeed()
if got := s.ScrollbackLen(); got != 0 {
t.Errorf("ScrollbackLen() = %d, want nothing remembered", got)
}
}
func TestScrollbackKeepsWhatLeavesTheTop(t *testing.T) {
s := NewScreen(10, 2)
for _, text := range []string{"one", "two", "three", "four"} {
writeString(s, text)
s.CarriageReturn()
s.LineFeed()
}
if got := s.ScrollbackLen(); got != 3 {
t.Fatalf("ScrollbackLen() = %d, want 3", got)
}
if got := lineText(s.ScrollbackLine(0)); got != "one" {
t.Errorf("the oldest scrollback line is %q, want %q", got, "one")
}
if s.ScrollbackLine(-1) != nil || s.ScrollbackLine(99) != nil {
t.Error("ScrollbackLine outside the history returned something")
}
}
func TestScrollbackIsCapped(t *testing.T) {
s := NewScreen(10, 2)
s.SetMaxScrollback(3)
for i := range 20 {
writeString(s, string(rune('a'+i%26)))
s.CarriageReturn()
s.LineFeed()
}
if got := s.ScrollbackLen(); got != 3 {
t.Errorf("ScrollbackLen() = %d, want the cap of 3", got)
}
}
func TestScrollbackCanBeTurnedOff(t *testing.T) {
s := NewScreen(10, 2)
s.SetMaxScrollback(0)
for range 5 {
s.LineFeed()
}
if got := s.ScrollbackLen(); got != 0 {
t.Errorf("ScrollbackLen() = %d, want none kept", got)
}
}
func TestTheAlternateScreenIsAScratchSurface(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "before")
s.UseAlternate(true)
if !s.Alternate() {
t.Fatal("Alternate() = false after switching to it")
}
wantLines(t, s, "")
if got := s.Cursor(); got != (Cursor{}) {
t.Errorf("Cursor() = %+v, want the top left of a fresh screen", got)
}
writeString(s, "during")
s.UseAlternate(false)
if s.Alternate() {
t.Fatal("Alternate() = true after switching back")
}
wantLines(t, s, "before")
}
func TestSwitchingToTheScreenAlreadyShowingDoesNothing(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "kept")
s.UseAlternate(false) // already on the primary
wantLines(t, s, "kept")
}
func TestTheAlternateScreenHasNoScrollback(t *testing.T) {
s := NewScreen(10, 2)
s.UseAlternate(true)
for range 5 {
s.LineFeed()
}
if got := s.ScrollbackLen(); got != 0 {
t.Errorf("ScrollbackLen() = %d, want none on a scratch surface", got)
}
}
func TestLeavingTheAlternateScreenBringsBackTheHistory(t *testing.T) {
s := NewScreen(10, 2)
for _, text := range []string{"one", "two", "three"} {
writeString(s, text)
s.CarriageReturn()
s.LineFeed()
}
before := s.ScrollbackLen()
s.UseAlternate(true)
s.UseAlternate(false)
if got := s.ScrollbackLen(); got != before {
t.Errorf("ScrollbackLen() = %d, want the %d lines from before", got, before)
}
}
func TestResizeKeepsWhatFits(t *testing.T) {
s := NewScreen(10, 3)
for row, text := range []string{"one", "two", "three"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.Resize(20, 5)
if width, height := s.Size(); width != 20 || height != 5 {
t.Fatalf("Size() = %dx%d, want 20x5", width, height)
}
wantLines(t, s, "one", "two", "three", "", "")
}
func TestShrinkingKeepsTheNewestLinesAndRemembersTheRest(t *testing.T) {
s := NewScreen(10, 4)
for row, text := range []string{"one", "two", "three", "four"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.Resize(10, 2)
wantLines(t, s, "three", "four")
if got := s.ScrollbackLen(); got != 2 {
t.Fatalf("ScrollbackLen() = %d, want the two lost lines kept", got)
}
if got := lineText(s.ScrollbackLine(0)); got != "one" {
t.Errorf("the oldest remembered line is %q, want %q", got, "one")
}
}
func TestShrinkingAMostlyEmptyScreenKeepsWhatIsOnIt(t *testing.T) {
// A command that prints one line and exits leaves the cursor near the top
// and the rest of the screen blank. Dropping rows from the top to make
// room then throws the output away while keeping blank rows below it —
// which is how "echo TADA" in a tool window showed nothing at all.
s := NewScreen(20, 24)
writeString(s, "TADA")
s.LineFeed()
s.CarriageReturn()
s.Resize(20, 20)
if got := lineText(s.Line(0)); got != "TADA" {
t.Errorf("the first row is %q, want the output still on screen", got)
}
if got := s.ScrollbackLen(); got != 0 {
t.Errorf("ScrollbackLen() = %d; nothing had scrolled off, so nothing should be remembered", got)
}
}
func TestShrinkingDropsOnlyAsManyRowsAsTheCursorNeeds(t *testing.T) {
// Halfway between the two cases: content down to row 5, cursor on row 5,
// shrunk to 4 rows. Two rows have to go for the cursor to fit, and only
// two should.
s := NewScreen(10, 10)
for row, text := range []string{"a", "b", "c", "d", "e", "f"} {
s.MoveTo(row, 0)
writeString(s, text)
}
s.Resize(10, 4)
wantLines(t, s, "c", "d", "e", "f")
if got := s.ScrollbackLen(); got != 2 {
t.Errorf("ScrollbackLen() = %d, want the two rows above the kept ones", got)
}
}
func TestNarrowingCutsColumnsRatherThanReflowing(t *testing.T) {
// No terminal reflows on resize, and pretending to would move text the
// program believes it has already placed.
s := NewScreen(10, 2)
writeString(s, "abcdefghij")
s.Resize(4, 2)
wantLines(t, s, "abcd")
}
func TestResizingToTheSameSizeChangesNothing(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "kept")
s.MoveTo(2, 5)
s.Resize(10, 3)
wantLines(t, s, "kept")
if got := s.Cursor(); got != (Cursor{Row: 2, Col: 5}) {
t.Errorf("Cursor() = %+v, want it untouched", got)
}
}
func TestResizingWhileOnTheAlternateScreenKeepsThePrimaryUsable(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "primary")
s.UseAlternate(true)
s.Resize(20, 6)
s.UseAlternate(false)
if width, height := s.Size(); width != 20 || height != 6 {
t.Fatalf("Size() = %dx%d, want 20x6", width, height)
}
wantLines(t, s, "primary")
if got := len(s.Line(0)); got != 20 {
t.Errorf("the restored line is %d cells wide, want 20", got)
}
}
func TestResizeClampsTheCursor(t *testing.T) {
s := NewScreen(10, 5)
s.MoveTo(4, 9)
s.Resize(4, 2)
got := s.Cursor()
if got.Row > 1 || got.Col > 3 {
t.Errorf("Cursor() = %+v, want it inside a 4x2 screen", got)
}
}
func TestResetPutsEverythingBack(t *testing.T) {
s := NewScreen(10, 3)
writeString(s, "text")
s.SetStyle(tcell.StyleDefault.Bold(true))
s.SetScrollRegion(1, 2)
s.SetCursorVisible(false)
s.UseAlternate(true)
s.Reset()
wantLines(t, s, "", "", "")
if s.Alternate() {
t.Error("Alternate() = true after a reset")
}
if !s.CursorVisible() {
t.Error("CursorVisible() = false after a reset")
}
if got := s.Cursor(); got != (Cursor{}) {
t.Errorf("Cursor() = %+v, want the top left", got)
}
if _, _, attrs := s.Style().Decompose(); attrs&tcell.AttrBold != 0 {
t.Error("the style survived a reset")
}
}
func TestCellAtAndLineOutsideTheScreen(t *testing.T) {
s := NewScreen(4, 2)
if got := s.CellAt(99, 0).Rune; got != ' ' {
t.Errorf("CellAt off the screen gave %q, want a space", got)
}
if s.Line(-1) != nil || s.Line(99) != nil {
t.Error("Line off the screen returned something")
}
if got := s.LineText(99); got != "" {
t.Errorf("LineText off the screen gave %q", got)
}
}
func TestErasingKeepsTheCurrentBackground(t *testing.T) {
// A program painting a coloured panel and then clearing a line inside it
// expects the panel's colour to stay, not a hole.
s := NewScreen(5, 2)
panel := tcell.StyleDefault.Background(tcell.ColorNavy)
s.SetStyle(panel)
s.EraseLine(EraseAll)
if _, background, _ := s.CellAt(0, 0).Style.Decompose(); background != tcell.ColorNavy {
t.Errorf("the erased cell has background %v, want navy", background)
}
}
// lineText renders a line as a string with its trailing blanks removed.
func lineText(line Line) string {
var out strings.Builder
for _, cell := range line {
out.WriteRune(cell.Rune)
}
return strings.TrimRight(out.String(), " ")
}
|