Add tests for the demo

.github/test.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+/usr/local/bin/cmake --version
+FACTOR=$1
+set -ex
+cd Polyhedron/demo
+LIST_OF_PLUGINS=$(/usr/local/bin/cmake --build . -t help | egrep 'plugin$' |& cut -d\  -f2)
+PLUGINS_ARRAY=(${LIST_OF_PLUGINS});
+NB_OF_PLUGINS=${#PLUGINS_ARRAY[@]}
+DEL=$(($NB_OF_PLUGINS / 4))
+mkdir build
+cd build
+/usr/local/bin/cmake -DCGAL_DIR=$2 ../Polyhedron
+make -j2 ${PLUGINS_ARRAY[@]:$(($FACTOR * $DEL)):$((($FACTOR + 1) * $DEL))}

.github/workflows/demo.yml

@@ -0,0 +1,37 @@
+name: Test Polyhedron Demo
+
+on: [push, pull_request]
+
+jobs:
+  batch_1:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.0.0
+    - name: install dependencies
+      run: .github/install.sh
+    - name: run1
+      run: ./.github/test.sh 0 ${{ github.workspace }}
+  batch_2:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.0.0
+    - name: install dependencies
+      run: .github/install.sh
+    - name: run2
+      run: ./.github/test.sh 1 ${{ github.workspace }}
+  batch_3:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.0.0
+    - name: install dependencies
+      run: .github/install.sh
+    - name: run3
+      run: ./.github/test.sh 2 ${{ github.workspace }}
+  batch_4:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2.0.0
+    - name: install dependencies
+      run: .github/install.sh
+    - name: run4
+      run: ./.github/test.sh 3 ${{ github.workspace }}