Tests: Add a pam test file

Hand-written in a text editor.

I verified that `convert` converts it to a png that looks like the
test expectations.

Tests/LibGfx/TestImageDecoder.cpp

@@ -15,6 +15,7 @@
 #include <LibGfx/ImageFormats/ImageDecoder.h>
 #include <LibGfx/ImageFormats/JPEGLoader.h>
 #include <LibGfx/ImageFormats/JPEGXLLoader.h>
+#include <LibGfx/ImageFormats/PAMLoader.h>
 #include <LibGfx/ImageFormats/PBMLoader.h>
 #include <LibGfx/ImageFormats/PGMLoader.h>
 #include <LibGfx/ImageFormats/PNGLoader.h>
@@ -444,6 +445,18 @@ TEST_CASE(test_jpeg_malformed_frame)
     }
 }
 
+TEST_CASE(test_pam_rgb)
+{
+    auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("pnm/2x1.pam"sv)));
+    EXPECT(Gfx::PAMImageDecoderPlugin::sniff(file->bytes()));
+    auto plugin_decoder = TRY_OR_FAIL(Gfx::PAMImageDecoderPlugin::create(file->bytes()));
+
+    auto frame = TRY_OR_FAIL(expect_single_frame(*plugin_decoder));
+    EXPECT_EQ(frame.image->size(), Gfx::IntSize(2, 1));
+    EXPECT_EQ(frame.image->get_pixel(0, 0), Gfx::Color('0', 'z', '0'));
+    EXPECT_EQ(frame.image->get_pixel(1, 0), Gfx::Color('0', '0', 'z'));
+}
+
 TEST_CASE(test_pbm)
 {
     auto file = TRY_OR_FAIL(Core::MappedFile::map(TEST_INPUT("pnm/buggie-raw.pbm"sv)));

Tests/LibGfx/test-inputs/pnm/2x1.pam

@@ -0,0 +1,8 @@
+P7
+WIDTH 2
+HEIGHT 1
+DEPTH 3
+MAXVAL 255
+TUPLTYPE RGB
+ENDHDR
+0z000z