diff --git a/tests/test-tokenizer-random.py b/tests/test-tokenizer-random.py
index f3447d482..4a5773fa5 100644
--- a/tests/test-tokenizer-random.py
+++ b/tests/test-tokenizer-random.py
@@ -472,10 +472,11 @@ def compare_tokenizers(tokenizer1: TokenizerGroundtruth, tokenizer2: TokenizerLl
     t_decode1 = 0
     t_decode2 = 0
     t_start = time.perf_counter()
+    total_tests = 0
+    failing_texts = set()
     encode_errors = 0
     decode_errors = 0
-    total_tests = 0
-    MAX_ERRORS = 10
+    MAX_ERRORS = 5
 
     logger.info("%s: %s" % (generator.__qualname__, "ini"))
     for text in generator:
@@ -494,13 +495,11 @@ def compare_tokenizers(tokenizer1: TokenizerGroundtruth, tokenizer2: TokenizerLl
         t_encode2 += t2 - t1
         t_decode1 += t3 - t2
         t_decode2 += t4 - t3
+        total_tests += 1
         # compare
         encode_ok = ids1 == ids2
         decode_ok = check_detokenizer(text, text1, text2)
-        encode_errors += not encode_ok
-        decode_errors += not decode_ok
-        total_tests += 1
-        if (encode_errors < MAX_ERRORS and not encode_ok) or (decode_errors < MAX_ERRORS and not decode_ok):
+        if not (encode_ok and decode_ok):
             def _compare(text: str):
                 ids1  = tokenizer1.encode(text)
                 ids2  = tokenizer2.encode(text)
@@ -510,33 +509,42 @@ def compare_tokenizers(tokenizer1: TokenizerGroundtruth, tokenizer2: TokenizerLl
                 decode_ok = check_detokenizer(text, text1, text2)
                 ok = encode_ok and decode_ok
                 return ok, ids1, ids2, text1, text2
+            # binary search upper and lower failing range
             a, b = 0, len(text)
-            for step in [64, 32, 16, 8, 4, 2, 1]:
-                while a < b:
-                    t = max(a, b - step)
-                    if _compare(text[a : t])[0]:
-                        break
-                    b = t
-            for step in [64, 32, 16, 8, 4, 2, 1]:
-                while a < b:
-                    t = min(a + step, b)
-                    if _compare(text[t : b])[0]:
-                        break
-                    a = t
+            step = b
+            while step > 1:
+                step = step // 2
+                if not _compare(text[a : b - step])[0]:
+                    b = b - step
+            step = b
+            while step > 1:
+                step = step // 2
+                if not _compare(text[a + step : b])[0]:
+                    a = a + step
             ok, ids1, ids2, text1, text2 = _compare(text[a : b])
             assert a <= b and not ok
-            logger.error(" Text:" + repr(text[a : b]))
-            logger.error("  " + " ".join(repr(x) + ":" + hex(ord(x)) for x in text[a : b]))
-            logger.error(" Expected: " + str(ids1))
-            logger.error("   Result: " + str(ids2))
-            logger.error(" Expected: " + " ".join(repr(x) + ":" + hex(ord(x)) for x in text1))
-            logger.error("   Result: " + " ".join(repr(x) + ":" + hex(ord(x)) for x in text2))
-            logger.error(f" {encode_errors=}")
-            logger.error(f" {decode_errors=}")
-        if encode_errors >= MAX_ERRORS and decode_errors >= MAX_ERRORS:
-            logger.error(f" EXIT: {encode_errors=} {decode_errors=}")
-            # raise Exception()
-            break
+            # show unique failing texts differences
+            failing_text = text[a : b]
+            if failing_text not in failing_texts:
+                failing_texts.add(failing_text)
+                if encode_errors < MAX_ERRORS and not encode_ok:
+                    encode_errors += 1
+                    logger.error(f" {encode_errors=}")
+                    logger.error(" Text:" + repr(failing_text))
+                    logger.error("  " + " ".join(repr(x) + ":" + hex(ord(x)) for x in failing_text))
+                    logger.error(" Expected: " + str(ids1))
+                    logger.error("   Result: " + str(ids2))
+                if decode_errors < MAX_ERRORS and not decode_ok:
+                    decode_errors += 1
+                    logger.error(f" {decode_errors=}")
+                    logger.error(" Text:" + repr(failing_text))
+                    logger.error("  " + " ".join(repr(x) + ":" + hex(ord(x)) for x in failing_text))
+                    logger.error(" Expected: " + " ".join(repr(x) + ":" + hex(ord(x)) for x in text1))
+                    logger.error("   Result: " + " ".join(repr(x) + ":" + hex(ord(x)) for x in text2))
+                if encode_errors >= MAX_ERRORS and decode_errors >= MAX_ERRORS:
+                    logger.error(f" EXIT: {encode_errors=} {decode_errors=}")
+                    # raise Exception()
+                    break
 
     t_total = time.perf_counter() - t_start
     logger.info(f"{generator.__qualname__}: end,  {t_encode1=:.3f} {t_encode2=:.3f}  {t_decode1=:.3f} {t_decode2=:.3f}  {t_total=:.3f}")
@@ -635,21 +643,19 @@ if __name__ == "__main__":
         "phi-3",          # SPM
         "gemma",          # SPM
         "gemma-2",        # SPM
-        "baichuan",       # SPM
+        # "baichuan",       # SPM
         "bert-bge",       # WPM
         "jina-v2-en",     # WPM
+        # "t5",             # UGM
         "llama-bpe",      # BPE
         "phi-2",          # BPE
         "deepseek-llm",   # BPE
         "deepseek-coder", # BPE
         "falcon",         # BPE
-        "mpt",            # BPE
         "starcoder",      # BPE
         "gpt-2",          # BPE
         "stablelm2",      # BPE
         "refact",         # BPE
-        "qwen2",          # BPE
-        "olmo",           # BPE
         "jina-v2-es",     # BPE
         "jina-v2-de",     # BPE
         "smaug-bpe",      # BPE
@@ -657,6 +663,14 @@ if __name__ == "__main__":
         "jina-v2-code",   # BPE
         "viking",         # BPE
         "jais",           # BPE
+        "codeshell",      # BPE
+        "tekken",         # BPE
+        "smollm",         # BPE
+        "mpt",            # BPE NFC
+        "command-r",      # BPE NFC
+        "qwen2",          # BPE NFC
+        "olmo",           # BPE NFC
+        "gpt-neox",       # BPE NFC
     ]
 
     logger.info("=" * 50)