Tests: Add a test for SOF0 images with several scans

This type of image isn't common, and you can probably only find one by
generating it yourself. It can be done using `cjpeg` with the -scan
argument.

This image has been generated with the following scan file:
0: 0 63 0 0;
1: 0 63 0 0;
2: 0 63 0 0;

1 files changed, 11 insertions, 0 deletions

diff --git a/Tests/LibGfx/TestImageDecoder.cpp b/Tests/LibGfx/TestImageDecoder.cpp
index 8021c77105..57d5270ad5 100644
--- a/Tests/LibGfx/TestImageDecoder.cpp
+++ b/Tests/LibGfx/TestImageDecoder.cpp
@@ -101,6 +101,17 @@ TEST_CASE(test_jpeg_sof0_one_scan)
     EXPECT(frame.duration == 0);
 }
 
+TEST_CASE(test_jpeg_sof0_several_scans)
+{
+    auto file = MUST(Core::MappedFile::map(TEST_INPUT("several_scans.jpg"sv)));
+    EXPECT(Gfx::JPEGImageDecoderPlugin::sniff(file->bytes()));
+    auto plugin_decoder = MUST(Gfx::JPEGImageDecoderPlugin::create(file->bytes()));
+    EXPECT(plugin_decoder->initialize());
+
+    auto frame = MUST(plugin_decoder->frame(0));
+    EXPECT_EQ(frame.image->size(), Gfx::IntSize(720, 859));
+}
+
 TEST_CASE(test_pbm)
 {
     auto file = MUST(Core::MappedFile::map(TEST_INPUT("buggie-raw.pbm"sv)));