From b02f2d89cdec0485637631880c7cb67e4becadd7 Mon Sep 17 00:00:00 2001
From: Yoan Blanc <yoan@dosimple.ch>
Date: Sun, 13 Nov 2016 15:46:37 +0100
Subject: [PATCH 1/2] Testing the formats that cannot be saved

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>
---
 vips_test.go | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/vips_test.go b/vips_test.go
index 6456a54..95c6658 100644
--- a/vips_test.go
+++ b/vips_test.go
@@ -29,15 +29,36 @@ func TestVipsRead(t *testing.T) {
 }
 
 func TestVipsSave(t *testing.T) {
-	image, _, _ := vipsRead(readImage("test.jpg"))
-	options := vipsSaveOptions{Quality: 95, Type: JPEG, Interlace: true}
+	types := [...]ImageType{JPEG, PNG, TIFF, WEBP}
 
-	buf, err := vipsSave(image, options)
-	if err != nil {
-		t.Fatal("Cannot save the image")
+	for _, typ := range types {
+		image, _, _ := vipsRead(readImage("test.jpg"))
+		options := vipsSaveOptions{Quality: 95, Type: typ}
+
+		buf, err := vipsSave(image, options)
+		if err != nil {
+			t.Fatalf("Cannot save the image as '%v'", ImageTypes[typ])
+		}
+		if len(buf) == 0 {
+			t.Fatalf("Empty saved '%v' image", ImageTypes[typ])
+		}
 	}
-	if len(buf) == 0 {
-		t.Fatal("Empty image")
+}
+
+func TestVipsCannotSave(t *testing.T) {
+	types := [...]ImageType{GIF, PDF, SVG, MAGICK}
+
+	for _, typ := range types {
+		image, _, _ := vipsRead(readImage("test.jpg"))
+		options := vipsSaveOptions{Quality: 95, Type: typ}
+
+		buf, err := vipsSave(image, options)
+		if err == nil {
+			t.Fatalf("Format '%v' shouldn't be supported", ImageTypes[typ])
+		}
+		if len(buf) != 0 {
+			t.Fatalf("'%v' image is not empty", ImageTypes[typ])
+		}
 	}
 }
 

From 5dd8611579d30ebc081adf7541dd0d4263c153b4 Mon Sep 17 00:00:00 2001
From: Yoan Blanc <yoan@dosimple.ch>
Date: Sun, 13 Nov 2016 15:47:33 +0100
Subject: [PATCH 2/2] Raise an error when trying to save as MAGICK type

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>
---
 vips.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/vips.go b/vips.go
index 0553170..1bbd6ed 100644
--- a/vips.go
+++ b/vips.go
@@ -380,6 +380,8 @@ func vipsSave(image *C.VipsImage, o vipsSaveOptions) ([]byte, error) {
 		return nil, errors.New("VIPS cannot save to PDF")
 	case SVG:
 		return nil, errors.New("VIPS cannot save to SVG")
+	case MAGICK:
+		return nil, errors.New("VIPS cannot save to MAGICK")
 	default:
 		saveErr = C.vips_jpegsave_bridge(tmpImage, &ptr, &length, 1, quality, interlace)
 		break