Tests: Add a zlib test for "missing end bits"

The actual cause for the "missing bits" is currently unknown, and this
test case doesn't actually start obviously breaking yet unless we start
reporting errors about missing bits. However, since we are touching the
BitStream implementation already, let's add the test early to make extra
sure that we aren't breaking anything.

Tests/LibCompress/TestZlib.cpp

@@ -42,3 +42,38 @@ TEST_CASE(zlib_compress_simple)
     auto const freshly_pressed = Compress::ZlibCompressor::compress_all({ uncompressed, sizeof(uncompressed) - 1 });
     EXPECT(freshly_pressed.value().bytes() == compressed.span());
 }
+
+TEST_CASE(zlib_decompress_with_missing_end_bits)
+{
+    // This test case has been extracted from compressed PNG data of `/res/icons/16x16/app-masterword.png`.
+    // The decompression results have been confirmed using the `zlib-flate` tool.
+    // Note: It is unconfirmed whether there are actually bits missing.
+    //       However, our decompressor implementation ends up in a weird state nonetheless.
+
+    Array<u8, 72> const compressed {
+        0x08, 0xD7, 0x63, 0x30, 0x86, 0x00, 0x01, 0x06, 0x23, 0x25, 0x30, 0x00,
+        0x32, 0x42, 0x95, 0x54, 0x83, 0xD0, 0x18, 0x41, 0xA1, 0x50, 0x46, 0x28,
+        0x8C, 0xA1, 0x8A, 0xA1, 0x46, 0xC5, 0x35, 0x48, 0xC9, 0x05, 0x99, 0xA1,
+        0xA4, 0xE2, 0x02, 0x44, 0x60, 0x93, 0x5D, 0x54, 0x54, 0x9C, 0x20, 0x0C,
+        0x17, 0x17, 0x08, 0x43, 0xC5, 0xC9, 0x05, 0xA8, 0x4B, 0x50, 0x50, 0x50,
+        0xC4, 0xD1, 0x45, 0x50, 0x80, 0x01, 0x06, 0x00, 0xB6, 0x1F, 0x15, 0xEF
+    };
+    Array<u8, 144> const decompressed {
+        0x00, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x10, 0x00, 0x32, 0x22,
+        0x22, 0x22, 0x22, 0x22, 0x22, 0x10, 0x00, 0x32, 0x55, 0x22, 0x25, 0x52,
+        0x22, 0x22, 0x10, 0x00, 0x32, 0x55, 0x22, 0x25, 0x52, 0x22, 0x22, 0x10,
+        0x00, 0x32, 0x55, 0x52, 0x55, 0x52, 0x22, 0x22, 0x10, 0x00, 0x32, 0x55,
+        0x55, 0x55, 0x52, 0x22, 0x22, 0x10, 0x00, 0x32, 0x55, 0x25, 0x25, 0x52,
+        0x22, 0x22, 0x10, 0x00, 0x32, 0x55, 0x22, 0x25, 0x52, 0x22, 0x22, 0x10,
+        0x00, 0x32, 0x55, 0x24, 0x45, 0x52, 0x22, 0x44, 0x10, 0x00, 0x32, 0x55,
+        0x24, 0x45, 0x52, 0x22, 0x44, 0x10, 0x00, 0x32, 0x22, 0x24, 0x44, 0x22,
+        0x24, 0x44, 0x10, 0x00, 0x32, 0x22, 0x22, 0x44, 0x24, 0x24, 0x42, 0x10,
+        0x00, 0x32, 0x22, 0x22, 0x44, 0x44, 0x44, 0x42, 0x10, 0x00, 0x32, 0x22,
+        0x22, 0x24, 0x42, 0x44, 0x22, 0x10, 0x00, 0x11, 0x11, 0x11, 0x14, 0x41,
+        0x44, 0x11, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+    };
+
+    auto const maybe_decompressed = Compress::ZlibDecompressor::decompress_all(compressed);
+    EXPECT(maybe_decompressed.has_value());
+    EXPECT_EQ(maybe_decompressed.value().span(), decompressed.span());
+}