tests for tokenizers. unfortunately use_fast=False and use_fast=True give different behaviour

test/test_mistral_tokenizer.py

@@ -0,0 +1,44 @@
+from transformers import AutoTokenizer, AutoProcessor
+
+
+def test_tokenizer(name, tokenizer, verbose=False):
+    print(f"--- {name} ({tokenizer.__class__.__name__}) ---")
+    text = "Hello! How can I assist you today? Let me know if you need help with something or just want to chat."
+    encoded = tokenizer.encode(text)
+    decoded = tokenizer.decode(encoded)
+
+    print(f"{encoded=}")
+    print(f"{decoded=}")
+
+    reconstructed = ""
+    for token in encoded:
+      if verbose:
+        print(f"{token=}")
+        print(f"{tokenizer.decode([token])=}")
+      reconstructed += tokenizer.decode([token])
+    print(f"{reconstructed=}")
+
+    strip_tokens = lambda s: s.lstrip(tokenizer.decode([tokenizer.bos_token_id])).rstrip(tokenizer.decode([tokenizer.eos_token_id]))
+    assert text == strip_tokens(decoded) == strip_tokens(reconstructed)
+
+# test_tokenizer(AutoTokenizer.from_pretrained("mlx-community/Mistral-Nemo-Instruct-2407-4bit"))
+models = [
+    "mlx-community/Meta-Llama-3.1-8B-Instruct-4bit",
+    "mlabonne/Meta-Llama-3.1-8B-Instruct-abliterated",
+    "mlx-community/Meta-Llama-3.1-70B-Instruct-4bit",
+    "NousResearch/Meta-Llama-3.1-70B",
+    "mlx-community/Meta-Llama-3.1-405B-4bit",
+    "mlx-community/Meta-Llama-3-8B-Instruct-4bit",
+    "mlx-community/Meta-Llama-3-70B-Instruct-4bit",
+    # "mlx-community/DeepSeek-Coder-V2-Lite-Instruct-4bit-mlx",
+    # "llava-hf/llava-1.5-7b-hf",
+    "mlx-community/Mistral-Nemo-Instruct-2407-4bit",
+    "mlx-community/Mistral-Large-Instruct-2407-4bit",
+]
+
+import os
+verbose = os.environ.get("VERBOSE", "0").lower() == "1"
+for m in models:
+    # test_tokenizer(m, AutoProcessor.from_pretrained(m, use_fast=False), verbose)
+    test_tokenizer(m, AutoProcessor.from_pretrained(m, use_fast=True), verbose)
+    test_tokenizer(m, AutoTokenizer.from_pretrained(m), verbose)