diff --git a/README.md b/README.md
index 9d6894a..96762ed 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,7 @@ For more information see also [my blog post](https://dev-investor.de/finanz-apps
 
 ```
 make dist
+make test
 ```
 
 The compiled MoneyMoney extension can then be found in `dist/SankeyChart.lua` and installed with `make install`.
diff --git a/package.json b/package.json
index 206fc83..a98f9ce 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,8 @@
   "author": "Christoph Massmann <chris@dev-investor.de>",
   "license": "MIT",
   "scripts": {
-    "test": "lua ./src/SankeyChartTest.lua | html-validate --stdin"
+    "test": "npm run test-compile-validate && npm run test-placeholder",
+    "test-compile-validate": "lua ./src/SankeyChartTest.lua | html-validate --stdin",
+    "test-placeholder": "grep -qE '\\${([A-Z_]+)}' dist/SankeyChart.lua && (echo 'ERROR: Placeholders have not been replaced in dist!' && exit 1) || exit 0"
   }
 }