waveshare2in13v2: Add test for New()

Ensure the internal buffer has the correct size and a few other
properties are correct.

Signed-off-by: Michael Hanselmann <public@hansmi.ch>

waveshare2in13v2/waveshare213v2_test.go

@@ -0,0 +1,73 @@
+// Copyright 2022 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package waveshare2in13v2
+
+import (
+	"image"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"periph.io/x/conn/v3/gpio"
+	"periph.io/x/conn/v3/gpio/gpiotest"
+	"periph.io/x/conn/v3/spi/spitest"
+	"periph.io/x/devices/v3/ssd1306/image1bit"
+)
+
+func TestNew(t *testing.T) {
+	for _, tc := range []struct {
+		name             string
+		opts             Opts
+		wantString       string
+		wantBounds       image.Rectangle
+		wantBufferBounds image.Rectangle
+	}{
+		{
+			name:       "empty",
+			wantString: "epd.Dev{playback, (0), Height: 0, Width: 0}",
+		},
+		{
+			name:             "EPD2in13v2",
+			opts:             EPD2in13v2,
+			wantBounds:       image.Rect(0, 0, 122, 250),
+			wantBufferBounds: image.Rect(0, 0, 128, 250),
+			wantString:       "epd.Dev{playback, (0), Height: 250, Width: 122}",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			dev, err := New(&spitest.Playback{}, &gpiotest.Pin{}, &gpiotest.Pin{}, &gpiotest.Pin{}, &gpiotest.Pin{
+				EdgesChan: make(chan gpio.Level, 1),
+			}, &tc.opts)
+			if err != nil {
+				t.Errorf("New() failed: %v", err)
+			}
+
+			if diff := cmp.Diff(dev.String(), tc.wantString); diff != "" {
+				t.Errorf("String() difference (-got +want):\n%s", diff)
+			}
+
+			if diff := cmp.Diff(dev.Bounds(), tc.wantBounds); diff != "" {
+				t.Errorf("Bounds() difference (-got +want):\n%s", diff)
+			}
+
+			if diff := cmp.Diff(dev.buffer.Bounds(), tc.wantBufferBounds); diff != "" {
+				t.Errorf("buffer.Bounds() difference (-got +want):\n%s", diff)
+			}
+
+			if !dev.buffer.Bounds().Empty() {
+				for _, pos := range []image.Point{
+					image.Pt(0, 0),
+					image.Pt(dev.buffer.Bounds().Max.X-1, 0),
+					image.Pt(dev.buffer.Bounds().Max.X-1, dev.buffer.Bounds().Max.Y-1),
+					image.Pt(0, dev.buffer.Bounds().Max.Y-1),
+					image.Pt(dev.buffer.Bounds().Dx()/2, dev.buffer.Bounds().Dy()/2),
+				} {
+					if diff := cmp.Diff(dev.buffer.BitAt(pos.X, pos.Y), image1bit.On); diff != "" {
+						t.Errorf("buffer.BitAt(%v) difference (-got +want):\n%s", pos, diff)
+					}
+				}
+			}
+		})
+	}
+}