fix documentation and add error message for missing jq

action.yml

@@ -9,7 +9,7 @@ inputs:
   customImage:
     required: false
     default: ''
-    description: 'Specific docker image that should be used for testing the project. If packageMode is true, this image must be compatible with apt-get.'
+    description: 'Specific docker image that should be used for testing the project. If packageMode is true, this image must have jq installed.'
   projectPath:
     required: false
     description: 'Path to the Unity project or package to be tested.'

dist/steps/run_tests.sh

@@ -43,6 +43,13 @@ echo "Using Unity version \"$UNITY_VERSION\" to test."
 if [ "$PACKAGE_MODE" = "true" ]; then
   echo "Running tests on a Unity package rather than a Unity project."
 
+  if ! command -v jq &> /dev/null
+  then
+      echo "jq could not be found. This is required for package mode, and is likely the result of using a custom Docker image. Please use the default image or install jq to your custom image."
+      exit
+  fi
+
+
   echo ""
   echo "###########################"
   echo "#    Package Folder       #"