Python - Test Decoders

bindings/python/tests/bindings/test_decoders.py

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+import pytest
+
+from tokenizers.decoders import Decoder, ByteLevel, WordPiece, Metaspace, BPEDecoder
+
+
+class TestByteLevel:
+    def test_instantiate(self):
+        assert ByteLevel() is not None
+        assert isinstance(ByteLevel(), Decoder)
+
+    def test_decoding(self):
+        decoder = ByteLevel()
+        assert decoder.decode(["My", "Ġname", "Ġis", "ĠJohn"]) == "My name is John"
+
+
+class TestWordPiece:
+    def test_instantiate(self):
+        assert WordPiece() is not None
+        assert WordPiece(prefix="__") is not None
+        assert WordPiece(cleanup=True) is not None
+        assert isinstance(WordPiece(), Decoder)
+
+    def test_decoding(self):
+        decoder = WordPiece()
+        assert decoder.decode(["My", "na", "##me", "is", "Jo", "##hn"]) == "My name is John"
+        assert decoder.decode(["I", "'m", "Jo", "##hn"]) == "I'm John"
+        decoder = WordPiece(prefix="__", cleanup=False)
+        assert decoder.decode(["My", "na", "__me", "is", "Jo", "__hn"]) == "My name is John"
+        assert decoder.decode(["I", "'m", "Jo", "__hn"]) == "I 'm John"
+
+
+class TestMetaspace:
+    def test_instantiate(self):
+        assert Metaspace() is not None
+        assert Metaspace(replacement="-") is not None
+        with pytest.raises(Exception, match="replacement must be a character"):
+            Metaspace(replacement="")
+        assert Metaspace(add_prefix_space=True) is not None
+        assert isinstance(Metaspace(), Decoder)
+
+    def test_decoding(self):
+        decoder = Metaspace()
+        assert decoder.decode(["▁My", "▁name", "▁is", "▁John"]) == "My name is John"
+        decoder = Metaspace(replacement="-", add_prefix_space=False)
+        assert decoder.decode(["-My", "-name", "-is", "-John"]) == " My name is John"
+
+
+class TestBPEDecoder:
+    def test_instantiate(self):
+        assert BPEDecoder() is not None
+        assert BPEDecoder(suffix="_") is not None
+        assert isinstance(BPEDecoder(), Decoder)
+
+    def test_decoding(self):
+        decoder = BPEDecoder()
+        assert (
+            decoder.decode(["My</w>", "na", "me</w>", "is</w>", "Jo", "hn</w>"])
+            == "My name is John"
+        )
+        decoder = BPEDecoder(suffix="_")
+        assert decoder.decode(["My_", "na", "me_", "is_", "Jo", "hn_"]) == "My name is John"