LibGfx/WOFF: Ensure header totalSfntSize matches expected value

Tests/LibGfx/CMakeLists.txt

@@ -9,6 +9,7 @@ set(TEST_SOURCES
     TestParseISOBMFF.cpp
     TestRect.cpp
     TestScalingFunctions.cpp
+    TestWOFF.cpp
 )
 
 foreach(source IN LISTS TEST_SOURCES)

Tests/LibGfx/TestWOFF.cpp

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2023, Tim Ledbetter <timledbetter@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibGfx/Font/WOFF/Font.h>
+#include <LibTest/TestCase.h>
+
+#ifdef AK_OS_SERENITY
+#    define TEST_INPUT(x) ("/usr/Tests/LibGfx/test-inputs/" x)
+#else
+#    define TEST_INPUT(x) ("test-inputs/" x)
+#endif
+
+TEST_CASE(malformed_woff)
+{
+    Array test_inputs = {
+        TEST_INPUT("woff/invalid_sfnt_size.woff"sv)
+    };
+
+    for (auto test_input : test_inputs) {
+        auto file = MUST(Core::MappedFile::map(test_input));
+        auto font_or_error = WOFF::Font::try_load_from_externally_owned_memory(file->bytes());
+        EXPECT(font_or_error.is_error());
+    }
+}