Add Tests for AdjustHue

Adds tests for the AdjustHue function.

adjust_test.go

@@ -247,6 +247,159 @@ func BenchmarkAdjustSaturation(b *testing.B) {
 	}
 }
 
+func TestAdjustHue(t *testing.T) {
+	testCases := []struct {
+		name string
+		src  image.Image
+		p    float64
+		want *image.NRGBA
+	}{
+		{
+			"AdjustHue 3x3 10",
+			&image.NRGBA{
+				Rect:   image.Rect(-1, -1, 2, 2),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+			10,
+			&image.NRGBA{
+				Rect:   image.Rect(0, 0, 3, 3),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x22, 0x01, 0x22, 0xcc, 0x00, 0x02, 0x00, 0x22, 0xcc, 0x03,
+					0x11, 0x28, 0x33, 0xff, 0x33, 0x1c, 0x11, 0xff, 0x93, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+		},
+		{
+			"AdjustHue 3x3 180",
+			&image.NRGBA{
+				Rect:   image.Rect(-1, -1, 2, 2),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+			180,
+			&image.NRGBA{
+				Rect:   image.Rect(0, 0, 3, 3),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0x00, 0xcc, 0xcc, 0x01, 0xcc, 0x00, 0xcc, 0x02, 0xcc, 0xcc, 0x00, 0x03,
+					0x33, 0x22, 0x11, 0xff, 0x11, 0x22, 0x33, 0xff, 0x44, 0xbb, 0x33, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+		},
+		{
+			"AdjustHue 3x3 -10",
+			&image.NRGBA{
+				Rect:   image.Rect(-1, -1, 2, 2),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+			-10,
+			&image.NRGBA{
+				Rect:   image.Rect(0, 0, 3, 3),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x22, 0x00, 0x01, 0x00, 0xcc, 0x22, 0x02, 0x22, 0x00, 0xcc, 0x03,
+					0x11, 0x1c, 0x33, 0xff, 0x33, 0x28, 0x11, 0xff, 0xbb, 0x33, 0xb5, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+		},
+		{
+			"AdjustHue 3x3 -180",
+			&image.NRGBA{
+				Rect:   image.Rect(-1, -1, 2, 2),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+			-180,
+			&image.NRGBA{
+				Rect:   image.Rect(0, 0, 3, 3),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0x00, 0xcc, 0xcc, 0x01, 0xcc, 0x00, 0xcc, 0x02, 0xcc, 0xcc, 0x00, 0x03,
+					0x33, 0x22, 0x11, 0xff, 0x11, 0x22, 0x33, 0xff, 0x44, 0xbb, 0x33, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+		},
+		{
+			"AdjustHue 3x3 0",
+			&image.NRGBA{
+				Rect:   image.Rect(-1, -1, 2, 2),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+			0,
+			&image.NRGBA{
+				Rect:   image.Rect(0, 0, 3, 3),
+				Stride: 3 * 4,
+				Pix: []uint8{
+					0xcc, 0x00, 0x00, 0x01, 0x00, 0xcc, 0x00, 0x02, 0x00, 0x00, 0xcc, 0x03,
+					0x11, 0x22, 0x33, 0xff, 0x33, 0x22, 0x11, 0xff, 0xaa, 0x33, 0xbb, 0xff,
+					0x00, 0x00, 0x00, 0xff, 0x33, 0x33, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff,
+				},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := AdjustHue(tc.src, tc.p)
+			if !compareNRGBA(got, tc.want, 0) {
+				t.Fatalf("got result %#v want %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestAdjustHueGolden(t *testing.T) {
+	for name, p := range map[string]float64{
+		"out_hue_m120.png": -120,
+		"out_hue_m60.png":  -60,
+		"out_hue_p60.png":  60,
+		"out_hue_p120.png": 120,
+	} {
+		got := AdjustHue(testdataFlowersSmallPNG, p)
+		want, err := Open("testdata/" + name)
+		if err != nil {
+			t.Fatalf("failed to open image: %v", err)
+		}
+		if !compareNRGBAGolden(got, toNRGBA(want)) {
+			t.Errorf("resulting image differs from golden: %s", name)
+		}
+	}
+}
+
+func BenchmarkAdjustHue(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		AdjustHue(testdataBranchesJPG, 10)
+	}
+}
+
 func TestAdjustContrast(t *testing.T) {
 	testCases := []struct {
 		name string