使用coverage，如何获取使用tavern编写的django项目的测试用例运行后的覆盖率？

Question

• 项目是Django项目，使用tarven结合pytest编写、测试
• 所有测试用例都是test_xxx.tavern.yaml格式的，语法严格按照tavern要求编写

requirements.txt

pytest==7.1.1
tavern==1.23.1
pytest-html==2.1.1
coverage==6.4.1
pytest-cov==3.0.0

tox.ini

[tox]
; The only reason we'd want to `sdist` is if we distributed 
; this as a Python package in PyPI, so let's skip it:
skipsdist = True
envlist =
    {py37}-django{2}
    lint
skip_missing_interpreters = true

[testenv]
whitelist_externals = *
passenv = *
deps = -rrequirements-test.txt
commands = {[testenv:unit]commands}

[testenv:unit]
deps = {[testenv]deps}
commands = pytest {posargs:--cov=djproject}


[pytest]
DJANGO_SETTINGS_MODULE = djproject.settings.local
python_files = test_*tavern.yaml
addopts =
    -v -s
    --color=yes
    --cov
    --cov-append
    --cov-report=term-missing
    --cov-config=tox.ini
    --ignore=venv
    --cov-report html
    --cov-fail-under=80


[coverage:report]
show_missing = True
omit =
    */usr/*
    */.tox/*py
    */.virtualenvs/*
    */migrations/*
    */tests/*
    */venv/*

[report]
omit =
    */usr/*
    */.tox/*
    */migrations/*
    */tests/*
    */venv/*

下面是项目的结构

vuserver
├── apitests
│   ├── all.html
│   ├── assets
│   │   └── style.css
│   ├── get-coverage.sh
│   ├── parallel
│   │   ├── includes.yaml
│   │   ├── test_01_init_gets.tavern.yaml
│   │   └── utils.py
│   ├── requirements-test.txt
├── assets
│   └── style.css
├── build_vuserver.sh
├── Dockerfile
├── __init__.py
├── manage.py
├── parallel
│   ├── admin.py
│   ├── capture.py
│   ├── consumers.py
│   ├── event.py
│   ├── __init__.py
│   ├── models.py
│   ├── serializers.py
│   ├── stat.py
│   ├── template.yml
│   ├── urls.py
│   └── views.py
├── pylintrc
├── requirements.txt
├── script
│   ├── admin.py
│   ├── apps.py
│   ├── __init__.py
│   ├── models.py
│   ├── nodejs
│   │   └── vtaas-v2default
│   ├── serializers.py
│   ├── urls.py
│   └── views.py
├── tox.ini
├── venv
│   ├── bin
│   ├── lib
│   │   └── python3.7
│   └── pyvenv.cfg
├── vuserver
│   ├── asgi.py
│   ├── __init__.py
│   ├── routing.py
│   ├── settings
│   │   ├── base.py
│   │   ├── __init__.py
│   │   ├── local.py
│   │   ├── __pycache__
│   │   └── production.py
│   ├── urls.py
│   └── wsgi.py

下面的脚本是我执行服务，进行单元测试获取覆盖率的脚本

set -xv

basepath=$(cd `dirname $0` || exit; pwd)
echo "$basepath"
cd "$basepath" || exit

cd ..

if [ -f "db.sqlite3" ];then
    rm -f "db.sqlite3"
fi

if [ -f ".coverage" ];then
    rm -f ".coverage"
fi

source venv/bin/activate
cd "apitests" || exit
pip install -r requirements-test.txt

cd ..
python manage.py migrate --settings=vuserver.settings.local
coverage erase
cd ..
find . -regex '*.pyc' -delete

coverage run ./manage.py runserver --noreload 0.0.0.0:9000 --settings=vuserver.settings.local &

pytest
sleep 5

coverage report -m
coverage html
pgrep -f 9000 | xargs kill -9

执行上述脚本，测试用例全部通过，可是覆盖率始终是0

Name                                             Stmts   Miss  Cover   Missing
------------------------------------------------------------------------------
__init__.py                                          2      2     0%   1-3
container_pool/admin.py                              9      9     0%   4-24
container_pool/apps.py                               3      3     0%   4-8
container_pool/deploy.py                           188    188     0%   4-263
container_pool/models.py                            60     60     0%   4-78
container_pool/serializers.py                        6      6     0%   4-11
container_pool/urls.py                               5      5     0%   5-12
container_pool/views.py                             27     27     0%   4-53
manage.py                                           13     13     0%   2-22
parallel/admin.py                                   21     21     0%   4-53
parallel/capture.py                                171    171     0%   4-285
parallel/consumers.py                               66     66     0%   4-151
parallel/event.py                                  290    290     0%   4-464
parallel/models.py                                 238    238     0%   4-313
parallel/serializers.py                            122    122     0%   4-252
parallel/stat.py                                   201    201     0%   4-273
parallel/urls.py                                    15     15     0%   4-20
parallel/views.py                                  635    635     0%   4-1013
script/admin.py                                      6      6     0%   4-13
script/apps.py                                       3      3     0%   4-8
script/models.py                                    25     25     0%   4-33
script/serializers.py                                6      6     0%   4-11
script/urls.py                                       4      4     0%   4-11
script/views.py                                    223    223     0%   4-331
vuserver/asgi.py                                     6      6     0%   1-7
vuserver/routing.py                                  5      5     0%   4-10
vuserver/settings/__init__.py                        8      8     0%   1-8
vuserver/settings/base.py                           50     50     0%   5-250
vuserver/settings/decc.py                           24     24     0%   4-60
vuserver/settings/local.py                          22     22     0%   4-43
vuserver/settings/staging.py                        29     29     0%   4-66
vuserver/urls.py                                    19     19     0%   4-38
vuserver/wsgi.py                                     4      4     0%   5-11
------------------------------------------------------------------------------
TOTAL                                             2572   2572     0%

请问如何才能获取到正确的覆盖率，问题出在上述哪一步，谢谢！