first commit

node_modules/fast-check/runkit.cjs

@@ -0,0 +1,15 @@
+const fc = require('fast-check');
+
+// Function under test
+function isSubstring(pattern, text) {
+  return text.indexOf(pattern) !== -1;
+}
+
+// Property based test
+fc.assert(
+  fc.property(fc.string(), fc.string(), fc.string(), (a, b, c) => {
+    // For any a, b, c strings
+    // b is a substring of a + b + c
+    return isSubstring(b, a + b + c);
+  }),
+);