Add test dependencies in requirement.txt file

.build.yml

@@ -0,0 +1,12 @@
+image: debian/buster
+packages:
+  - python3-pip
+  - virtualenv
+tasks:
+  - test: |
+      cd yt-local
+      virtualenv -p python3 venv
+      source venv/bin/activate
+      python --version
+      pip install -r requirements-dev.txt
+      pytest

requirements-dev.txt

@@ -1 +1,27 @@
+attrs==20.3.0
+Brotli==1.0.9
+cachetools==4.2.0
+click==7.1.2
+defusedxml==0.6.0
+Flask==1.1.2
+gevent==20.9.0
+greenlet==0.4.17
+importlib-metadata==3.7.0
+iniconfig==1.1.1
+itsdangerous==1.1.0
+Jinja2==2.11.2
+MarkupSafe==1.1.1
+packaging==20.9
+pluggy==0.13.1
+py==1.10.0
+pyparsing==2.4.7
+PySocks==1.7.1
 pytest>=6.2.1
+stem==1.8.0
+toml==0.10.2
+typing-extensions==3.7.4.3
+urllib3==1.26.2
+Werkzeug==1.0.1
+zipp==3.4.0
+zope.event==4.5.0
+zope.interface==5.2.0