Python tests revival

This PR does a bit of tidying to bring back in the python tests.

This mainly kills off the broken tests from before the grand schism with TGI, which was mainly tests/models and things involving StoppingCriteria. After fixing a few other tests that seem to have been broken by recent changes, make python-tests is good to go again.

Author: joerunde

server/tests/conftest.py

@@ -1,41 +1 @@
-import pytest
-
-from transformers import AutoTokenizer
-
-from text_generation_server.pb import generate_pb2
-
-
-@pytest.fixture
-def default_pb_parameters():
-    return generate_pb2.NextTokenChooserParameters(
-        temperature=0.0,  # Greedy
-        top_k=0,
-        top_p=1.0,
-        #do_sample=False,
-    )
-
-
-@pytest.fixture
-def default_pb_stop_parameters():
-    return generate_pb2.StoppingCriteriaParameters(stop_sequences=[], max_new_tokens=10)
-
-
-@pytest.fixture(scope="session")
-def bloom_560m_tokenizer():
-    return AutoTokenizer.from_pretrained("bigscience/bloom-560m", padding_side="left")
-
-
-@pytest.fixture(scope="session")
-def gpt2_tokenizer():
-    tokenizer = AutoTokenizer.from_pretrained("gpt2", padding_side="left")
-    tokenizer.pad_token_id = 50256
-    return tokenizer
-
-
-@pytest.fixture(scope="session")
-def mt0_small_tokenizer():
-    tokenizer = AutoTokenizer.from_pretrained(
-        "bigscience/mt0-small", padding_side="left"
-    )
-    tokenizer.bos_token_id = 0
-    return tokenizer
+"""nada"""