Improve line editing

Correctly support moving around the text and placing glyphs at any
position.

1 files changed, 107 insertions, 0 deletions

diff --git a/ui/editor_test.go b/ui/editor_test.go
new file mode 100644
index 0000000..9f4e131
--- /dev/null
+++ b/ui/editor_test.go
@@ -0,0 +1,107 @@
+package ui
+
+import "testing"
+
+var hell editor = editor{
+	text:      []rune{'h', 'e', 'l', 'l'},
+	textWidth: []int{0, 1, 2, 3, 4},
+	cursorIdx: 4,
+	offsetIdx: 0,
+	width:     5,
+}
+
+func assertEditorEq(t *testing.T, actual, expected editor) {
+	if len(actual.text) != len(expected.text) {
+		t.Errorf("expected text len to be %d, got %d\n", len(expected.text), len(actual.text))
+	} else {
+		for i := 0; i < len(actual.text); i++ {
+			a := actual.text[i]
+			e := expected.text[i]
+
+			if a != e {
+				t.Errorf("expected rune #%d to be '%c', got '%c'\n", i, e, a)
+			}
+		}
+	}
+
+	if len(actual.textWidth) != len(expected.textWidth) {
+		t.Errorf("expected textWidth len to be %d, got %d\n", len(expected.textWidth), len(actual.textWidth))
+	} else {
+		for i := 0; i < len(actual.textWidth); i++ {
+			a := actual.textWidth[i]
+			e := expected.textWidth[i]
+
+			if a != e {
+				t.Errorf("expected width #%d to be %d, got %d\n", i, e, a)
+			}
+		}
+	}
+
+	if actual.cursorIdx != expected.cursorIdx {
+		t.Errorf("expected cursorIdx to be %d, got %d\n", expected.cursorIdx, actual.cursorIdx)
+	}
+
+	if actual.offsetIdx != expected.offsetIdx {
+		t.Errorf("expected offsetIdx to be %d, got %d\n", expected.offsetIdx, actual.offsetIdx)
+	}
+
+	if actual.width != expected.width {
+		t.Errorf("expected width to be %d, got %d\n", expected.width, actual.width)
+	}
+}
+
+func TestOneLetter(t *testing.T) {
+	e := newEditor(5)
+	e.PutRune('h')
+	assertEditorEq(t, e, editor{
+		text:      []rune{'h'},
+		textWidth: []int{0, 1},
+		cursorIdx: 1,
+		offsetIdx: 0,
+		width:     5,
+	})
+}
+
+func TestFourLetters(t *testing.T) {
+	e := newEditor(5)
+	e.PutRune('h')
+	e.PutRune('e')
+	e.PutRune('l')
+	e.PutRune('l')
+	assertEditorEq(t, e, hell)
+}
+
+func TestOneLeft(t *testing.T) {
+	e := newEditor(5)
+	e.PutRune('h')
+	e.PutRune('l')
+	e.Left()
+	e.PutRune('e')
+	e.PutRune('l')
+	e.Right()
+	assertEditorEq(t, e, hell)
+}
+
+func TestOneRem(t *testing.T) {
+	e := newEditor(5)
+	e.PutRune('h')
+	e.PutRune('l')
+	e.RemRune()
+	e.PutRune('e')
+	e.PutRune('l')
+	e.PutRune('l')
+	assertEditorEq(t, e, hell)
+}
+
+func TestLeftAndRem(t *testing.T) {
+	e := newEditor(5)
+	e.PutRune('h')
+	e.PutRune('l')
+	e.PutRune('e')
+	e.Left()
+	e.RemRune()
+	e.Right()
+	e.PutRune('l')
+	e.PutRune('l')
+	assertEditorEq(t, e, hell)
+}