From ffec83a001be70c169726b56cc293a839366c51f Mon Sep 17 00:00:00 2001
From: Elias Naur <mail@eliasnaur.com>
Date: Sat, 20 Jun 2020 16:03:46 +0200
Subject: [PATCH] widget: add Editor tests

Signed-off-by: Elias Naur <mail@eliasnaur.com>
---
 widget/editor_test.go | 139 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 widget/editor_test.go

diff --git a/widget/editor_test.go b/widget/editor_test.go
new file mode 100644
index 00000000..538e1ad9
--- /dev/null
+++ b/widget/editor_test.go
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package widget
+
+import (
+	"fmt"
+	"image"
+	"math/rand"
+	"reflect"
+	"testing"
+	"testing/quick"
+
+	"gioui.org/f32"
+	"gioui.org/font/gofont"
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/text"
+	"gioui.org/unit"
+)
+
+func TestEditor(t *testing.T) {
+	e := new(Editor)
+	gtx := layout.Context{
+		Ops:         new(op.Ops),
+		Constraints: layout.Exact(image.Pt(100, 100)),
+	}
+	cache := text.NewCache(gofont.Collection())
+	fontSize := unit.Px(10)
+	font := text.Font{}
+
+	e.SetText("æbc\naøå•")
+	e.Layout(gtx, cache, font, fontSize)
+	assertCaret(t, e, 0, 0, 0)
+	e.moveEnd()
+	assertCaret(t, e, 0, 3, len("æbc"))
+	e.Move(+1)
+	assertCaret(t, e, 1, 0, len("æbc\n"))
+	e.Move(-1)
+	assertCaret(t, e, 0, 3, len("æbc"))
+	e.moveLines(+1)
+	assertCaret(t, e, 1, 3, len("æbc\naøå"))
+	e.moveEnd()
+	assertCaret(t, e, 1, 4, len("æbc\naøå•"))
+	e.Move(+1)
+	assertCaret(t, e, 1, 4, len("æbc\naøå•"))
+}
+
+// assertCaret asserts that the editor caret is at a particular line
+// and column, and that the byte position matches as well.
+func assertCaret(t *testing.T, e *Editor, line, col, bytes int) {
+	t.Helper()
+	gotLine, gotCol := e.CaretPos()
+	if gotLine != line || gotCol != col {
+		t.Errorf("caret at (%d, %d), expected (%d, %d)", gotLine, gotCol, line, col)
+	}
+	if bytes != e.rr.caret {
+		t.Errorf("caret at buffer position %d, expected %d", e.rr.caret, bytes)
+	}
+}
+
+type editMutation int
+
+const (
+	setText editMutation = iota
+	moveRune
+	moveLine
+	movePage
+	moveStart
+	moveEnd
+	moveCoord
+	moveLast // Mark end; never generated.
+)
+
+func TestEditorCaretConsistency(t *testing.T) {
+	gtx := layout.Context{
+		Ops:         new(op.Ops),
+		Constraints: layout.Exact(image.Pt(100, 100)),
+	}
+	cache := text.NewCache(gofont.Collection())
+	fontSize := unit.Px(10)
+	font := text.Font{}
+	for _, a := range []text.Alignment{text.Start, text.Middle, text.End} {
+		e := &Editor{
+			Alignment: a,
+		}
+		e.Layout(gtx, cache, font, fontSize)
+
+		consistent := func() error {
+			t.Helper()
+			gotLine, gotCol := e.CaretPos()
+			gotCoords := e.CaretCoords()
+			wantLine, wantCol, wantX, wantY := e.layoutCaret()
+			wantCoords := f32.Pt(float32(wantX)/64, float32(wantY))
+			if wantLine == gotLine && wantCol == gotCol && gotCoords == wantCoords {
+				return nil
+			}
+			return fmt.Errorf("caret (%d,%d) pos %s, want (%d,%d) pos %s", gotLine, gotCol, gotCoords, wantLine, wantCol, wantCoords)
+		}
+		if err := consistent(); err != nil {
+			t.Errorf("initial editor inconsistency (alignment %s): %v", a, err)
+		}
+
+		move := func(mutation editMutation, str string, distance int8, x, y uint16) bool {
+			switch mutation {
+			case setText:
+				e.SetText(str)
+				e.Layout(gtx, cache, font, fontSize)
+			case moveRune:
+				e.Move(int(distance))
+			case moveLine:
+				e.moveLines(int(distance))
+			case movePage:
+				e.movePages(int(distance))
+			case moveStart:
+				e.moveStart()
+			case moveEnd:
+				e.moveEnd()
+			case moveCoord:
+				e.moveCoord(image.Pt(int(x), int(y)))
+			default:
+				return false
+			}
+			if err := consistent(); err != nil {
+				t.Error(err)
+				return false
+			}
+			return true
+		}
+		if err := quick.Check(move, nil); err != nil {
+			t.Errorf("editor inconsistency (alignment %s): %v", a, err)
+		}
+	}
+}
+
+// Generate generates a value of itself, for testing/quick.
+func (editMutation) Generate(rand *rand.Rand, size int) reflect.Value {
+	t := editMutation(rand.Intn(int(moveLast)))
+	return reflect.ValueOf(t)
+}