Add ESP32 to Travis CI

Author: sandeepmistry

.travis.yml

@@ -4,11 +4,19 @@ env:
     - IDE_VERSION=1.8.5
   matrix:
     - BOARD="arduino:avr:uno"
+    - BOARD="espressif:esp32:esp32"
 before_install:
   - wget http://downloads.arduino.cc/arduino-$IDE_VERSION-linux64.tar.xz
   - tar xf arduino-$IDE_VERSION-linux64.tar.xz
   - mv arduino-$IDE_VERSION $HOME/arduino-ide
   - export PATH=$PATH:$HOME/arduino-ide
+  - if [[ "$BOARD" =~ "espressif:esp32:" ]]; then
+      mkdir -p $HOME/Arduino/hardware/espressif;
+      git clone https://github.com/espressif/arduino-esp32.git $HOME/Arduino/hardware/espressif/esp32;
+      pushd $HOME/Arduino/hardware/espressif/esp32/tools/;
+      python get.py;
+      popd;
+    fi
   - buildExampleSketch() { arduino --verbose-build --verify --board $BOARD $PWD/examples/$1/$1.ino; }
 install:
   - mkdir -p $HOME/Arduino/libraries