ivtest: Create the vvp_reg.py test script

This creates a new test suite driver and infrastructure for going
forward. This cleans up the descriptions for tests, and is more
extensible.

Include documentation for the new engine, so that new tests can go
here instead of the old test suite.

.github/workflows/test.yml

@@ -22,6 +22,7 @@ jobs:
     - name: Install dependencies
       run: |
         brew install bison
+        pip3 install docopt
 
     - name: Build, check and install
       run: |
@@ -52,7 +53,7 @@ jobs:
     - name: Install dependencies
       run: |
         sudo apt update -qq
-        sudo apt install -y make g++ git bison flex gperf libreadline-dev autoconf python3-sphinx
+        sudo apt install -y make g++ git bison flex gperf libreadline-dev autoconf python3-sphinx python3-docopt
 
     - name: Build, check and install
       run: |
@@ -99,8 +100,11 @@ jobs:
           git
           base-devel
           gperf
+          python-pip
           mingw-w64-${{ matrix.arch }}-toolchain
 
+    - uses: actions/setup-python@v4
+
     - name: Build and check
       run: |
         cd msys2
@@ -110,7 +114,8 @@ jobs:
       run: pacman -U --noconfirm msys2/*.zst
 
     - name: Test
-      run: ./.github/test.sh
+      run: |
+        ./.github/test.sh
 
     - uses: actions/upload-artifact@v2
       with: