Write a python "test_runner" python script, it should do the following:
1. Read test plan from a json file, it should be a list of various model_backend (only accept "koboldcpp", "llamacpp", "llamapy"), model_backend_host (if using "koboldcpp" or "llamacpp" backends), model_path, model_format, context_size, thread_number
2. For each item in the test plan list, run an executable with this line of command: server_cublas.exe -m "{model_path}" -t {thread_number} -c {context_size}
3. After that, run a python script with this line of command: main.py --format {model_format} --lcpp-host {model_backend_host}
4. Wait the python script to end and then restart from item 1 for the next item in the test plan list Respond with at most 400 words.
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