Move test dependencies into a requirements.txt

Having them as extras misleads some tools into thinking the test
dependencies are optional runtime dependencies. The installation of
pytest-order from GitHub is now also blocked by PyPI.

.github/workflows/test-pgcc.yml

@@ -28,5 +28,5 @@ jobs:
         working-directory: /opt/
 
       - run: pip install setuptools wheel
-      - run: pip install -e .[test]
+      - run: pip install -e . -r tests/requirements.txt
       - run: CC=pgcc ./test

.github/workflows/test.yml

@@ -39,7 +39,7 @@ jobs:
           architecture: ${{ matrix.architecture }}
 
       - run: pip install -U wheel psutil setuptools
-      - run: pip install -e .[test]
+      - run: pip install -e . -r tests/requirements.txt
 
       - name: Show gcc
         run: gcc -v

Dockerfile_alpine

@@ -15,4 +15,4 @@ RUN apk add gcc musl-dev
 ENV FORCE_COLOR=1
 COPY . /io
 WORKDIR /io
-RUN pip install --prefer-binary -e .[test]
+RUN pip install --prefer-binary -e . -r tests/requirements.txt

Dockerfile_manylinux

@@ -33,7 +33,7 @@ COPY README.rst /io/README.rst
 # Set the repo's root as the cwd.
 WORKDIR /io
 # Install more dependencies.
-RUN pip install --prefer-binary -e .[test]
+RUN pip install --prefer-binary -e . -r tests/requirements.txt
 # Work around new metapath nonsense
 RUN ln -s /io/cslug /opt/python/cp39-cp39/lib/python3.9/site-packages/cslug
 # Copy across this repo.

Vagrantfile

@@ -6,7 +6,7 @@ Vagrant.configure("2") do |config|
     machine.vm.provision "shell", privileged: false, inline:<<-END
       sudo pkg update
       sudo pkg install -y fish py39-pip py39-sqlite3
-      cd /io && pip install -e .[test] psutil
+      cd /io && pip install -e . -r tests/requirements.txt psutil
     END
     setup_shell(machine)
     shimify_python(machine, "python3.9")
@@ -17,7 +17,7 @@ Vagrant.configure("2") do |config|
     setup_rsync(machine)
     machine.vm.provision "shell", privileged: false, inline:<<-END
       sudo pkg_add fish py3-pip
-      cd /io && pip install -e .[test]
+      cd /io && pip install -e . -r tests/requirements.txt
     END
     setup_shell(machine)
     shimify_python(machine, "python3")
@@ -32,7 +32,7 @@ Vagrant.configure("2") do |config|
     setup_shell(machine)
     shimify_python(machine, "python3.9")
     machine.vm.provision "shell", privileged: false, inline:<<-END
-      cd /io && pip install -e .[test] psutil
+      cd /io && pip install -e . -r tests/requirements.txt psutil
     END
   end
 

tests/README.md

@@ -4,7 +4,7 @@ Test requirements are specified as an extras-require.
 Run from the root of this repo:
 
 ```shell
-pip install -e .[test]
+pip install -e . -r tests/requirements.txt
 ```
 
 Then invoke tests using: