Add test for get_missing_glyphs for encoding 3 and 4

Author: moi15moi

tests/file/fonts/微软简标宋 - PlatEncID 3.TTF

@@ -105,9 +105,7 @@ def test_get_name_encoding():
 
 
 def test_get_decoded_name():
-    # The string are from the font in this pack: https://github.com/libass/libass/issues/643#issuecomment-1476459274
-
-    # 微软简标宋 - PlatEncID 3.TTF
+    # tests\fonts\微软简标宋 - PlatEncID 3.TTF
     name_record = NameRecord()
     name_record.nameID = 1
     name_record.string = b"\x00\xce\x00\xa2\x00\xc8\x00\xed\x00\xbc\x00\xf2\x00\xb1\x00\xea\x00\xcb\x00\xce"
@@ -116,7 +114,7 @@ def test_get_decoded_name():
     name_record.langID = 0
     Name.get_decoded_name_record(name_record) == "微软简标宋"
 
-    # 文鼎中特廣告體 - PlatEncID 4.ttf
+    # tests\fonts\文鼎中特廣告體 - PlatEncID 4.ttf
     name_record = NameRecord()
     name_record.nameID = 1
     name_record.string = b"\x00\xa4\x00\xe5\x00\xb9\x00\xa9\x00\xa4\x00\xa4\x00\xaf\x00S\x00\xbc\x00s\x00\xa7\x00i\x00\xc5\x00\xe9"

tests/file/fonts/文鼎中特廣告體 - PlatEncID 4.ttf

@@ -185,6 +185,32 @@ def test_font_get_missing_glyphs_cmap_encoding_2():
     assert missing_glyphs == {"é"}
 
 
+def test_font_get_missing_glyphs_cmap_encoding_3():
+    font_cmap_encoding_3 = Path(os.path.join(os.path.dirname(dir_path), "file", "fonts", "微软简标宋 - PlatEncID 3.TTF"))
+    font_file = FontFile.from_font_path(font_cmap_encoding_3)
+
+    assert len(font_file.font_faces) == 1
+    font_face = font_file.font_faces[0]
+    assert isinstance(font_face, NormalFontFace)
+
+    # Try "ｦ" since cp936 doesn't support this char
+    missing_glyphs = font_face.get_missing_glyphs("AÉé㈤ｦ")
+    assert missing_glyphs == {"É", "ｦ"}
+
+
+def test_font_get_missing_glyphs_cmap_encoding_4():
+    font_cmap_encoding_4 = Path(os.path.join(os.path.dirname(dir_path), "file", "fonts", "文鼎中特廣告體 - PlatEncID 4.ttf"))
+    font_file = FontFile.from_font_path(font_cmap_encoding_4)
+
+    assert len(font_file.font_faces) == 1
+    font_face = font_file.font_faces[0]
+    assert isinstance(font_face, NormalFontFace)
+
+    # Try "ｦ" since cp950 doesn't support this char
+    missing_glyphs = font_face.get_missing_glyphs("é￥卷ｦ")
+    assert missing_glyphs == {"é", "ｦ"}
+
+
 def test_font_get_missing_glyphs_cmap_legacy_arabic_simplified():
     font_path = Path(os.path.join(os.path.dirname(dir_path), "file", "fonts", "legacy-arabic-simplified-SimplifiedArabic.ttf"))
     font_file = FontFile.from_font_path(font_path)