Add example test script

.travis.yml

@@ -9,6 +9,7 @@ install:
 - pip install .[all] --progress-bar off
 script:
 - coverage run -m pytest
+- ./tests/test_examples.sh examples/
 after_success:
 - bash <(curl -s https://codecov.io/bash)
 deploy:

tests/test_examples.sh

@@ -0,0 +1,10 @@
+#! /bin/bash
+
+for example in $(find $1 -maxdepth 1 -name "*.py")
+do
+    echo "test:" $example
+    export DISPLAY= && python $example --fast_dev_run 1
+    if [[ $? -ne 0 ]]; then
+        exit 1
+    fi
+done