1package clib
 2
 3import (
 4	"bytes"
 5	"image"
 6	"image/color"
 7	"image/png"
 8	"testing"
 9)
10
11// createTestPNG generates a small PNG image in memory for testing.
12func createTestPNG(w, h int) []byte {
13	img := image.NewRGBA(image.Rect(0, 0, w, h))
14	for y := 0; y < h; y++ {
15		for x := 0; x < w; x++ {
16			img.Set(x, y, color.RGBA{R: uint8(x), G: uint8(y), B: 128, A: 255})
17		}
18	}
19	var buf bytes.Buffer
20	png.Encode(&buf, img)
21	return buf.Bytes()
22}
23
24func TestDecodeToPNGValid(t *testing.T) {
25	input := createTestPNG(16, 32)
26
27	result, ok := DecodeToPNG(input)
28	if !ok {
29		t.Fatal("DecodeToPNG failed for valid PNG")
30	}
31	if result.Width != 16 {
32		t.Errorf("expected width=16, got %d", result.Width)
33	}
34	if result.Height != 32 {
35		t.Errorf("expected height=32, got %d", result.Height)
36	}
37	if len(result.PNGData) == 0 {
38		t.Error("expected non-empty PNG data")
39	}
40
41	// Verify output is valid PNG by decoding with Go
42	img, err := png.Decode(bytes.NewReader(result.PNGData))
43	if err != nil {
44		t.Fatalf("output is not valid PNG: %v", err)
45	}
46	if img.Bounds().Dx() != 16 || img.Bounds().Dy() != 32 {
47		t.Errorf("decoded dimensions mismatch: got %dx%d", img.Bounds().Dx(), img.Bounds().Dy())
48	}
49}
50
51func TestDecodeToPNGEmpty(t *testing.T) {
52	_, ok := DecodeToPNG(nil)
53	if ok {
54		t.Error("expected failure for nil input")
55	}
56
57	_, ok = DecodeToPNG([]byte{})
58	if ok {
59		t.Error("expected failure for empty input")
60	}
61}
62
63func TestDecodeToPNGInvalid(t *testing.T) {
64	_, ok := DecodeToPNG([]byte("not an image"))
65	if ok {
66		t.Error("expected failure for invalid image data")
67	}
68}
69
70func TestImageDimensionsValid(t *testing.T) {
71	input := createTestPNG(64, 48)
72
73	w, h, ok := ImageDimensions(input)
74	if !ok {
75		t.Fatal("ImageDimensions failed for valid PNG")
76	}
77	if w != 64 {
78		t.Errorf("expected width=64, got %d", w)
79	}
80	if h != 48 {
81		t.Errorf("expected height=48, got %d", h)
82	}
83}
84
85func TestImageDimensionsEmpty(t *testing.T) {
86	_, _, ok := ImageDimensions(nil)
87	if ok {
88		t.Error("expected failure for nil input")
89	}
90}
91
92func TestImageDimensionsInvalid(t *testing.T) {
93	_, _, ok := ImageDimensions([]byte("garbage"))
94	if ok {
95		t.Error("expected failure for invalid data")
96	}
97}