ct.models.utils.bisect_model requires pytest to be installed

[atiorh]

🐞Describing the bug

ct.models.utils.bisect_model requires pytest to be installed

To Reproduce

pip install coremltools && python -c "import coremltools as ct;ct.models.utils.bisect_model(...)"

[TobyRoseman]

I can reproduce this issue. Here is the stack trace:

File ~/miniconda3/envs/prod/lib/python3.10/site-packages/coremltools/models/utils.py:2006, in bisect_model(model, output_dir, merge_chunks_to_pipeline, check_output_correctness)
   2003     else:
   2004         mlmodel = model
-> 2006     _verify_output_correctness_of_chunks(
   2007         full_model=mlmodel,
   2008         first_chunk_model=model_chunk1,
   2009         second_chunk_model=model_chunk2,
   2010     )
   2012 # save model chunks
   2013 _os.makedirs(output_dir, exist_ok=True)

File ~/miniconda3/envs/prod/lib/python3.10/site-packages/coremltools/models/utils.py:2056, in _verify_output_correctness_of_chunks(full_model, first_chunk_model, second_chunk_model, pipeline_model)
   2054 """Verifies the end-to-end output correctness of full (original) model versus chunked models"""
   2055 # lazy import avoids circular error
-> 2056 from coremltools.converters.mil.testing_utils import compute_snr_and_psnr
   2057 from coremltools.converters.mil.testing_utils import (
   2058     random_gen_input_feature_type as random_gen_input_feature_type,
   2059 )
   2061 def report_correctness(original_outputs: _np.ndarray, final_outputs: _np.ndarray, log_prefix: str):

File ~/miniconda3/envs/prod/lib/python3.10/site-packages/coremltools/converters/mil/testing_utils.py:13
     10 from typing import Dict, List, Optional, Tuple, Union
     12 import numpy as np
---> 13 import pytest
     14 from PIL import Image
     16 import coremltools as ct

ModuleNotFoundError: No module named 'pytest'