diff --git a/ventures/box-art-night/test.js b/ventures/box-art-night/test.js
new file mode 100644
index 0000000..e4a2744
--- /dev/null
+++ b/ventures/box-art-night/test.js
@@ -0,0 +1,12 @@
+// Self-check for the pure helpers: node ventures/box-art-night/test.js
+const assert = require('assert');
+const { hash, parseStats, wrap } = require('./app.js');
+assert.strictEqual(hash('a'), hash('a'));
+assert.notStrictEqual(hash('a'), hash('b'));
+assert.deepStrictEqual(parseStats('Players: 1\n\n Price : Free: yes \nNo colon\nx: y\nz: w', 4),
+  [['Players', '1'], ['Price', 'Free: yes'], ['', 'No colon'], ['x', 'y']]);
+const m = s => s.length * 10;
+assert.deepStrictEqual(wrap(m, 'aa bb cc dd', 50, 5), ['aa bb', 'cc dd']);
+assert.deepStrictEqual(wrap(m, 'aa bb cc dd', 50, 1), ['aa b…'.length * 10 <= 50 ? 'aa b…' : 'aa…']);
+assert.deepStrictEqual(wrap(m, '', 50, 2), []);
+console.log('ok');