WIP

test/utils.js

@@ -12,6 +12,36 @@ Object.assign(globalThis,
   }
 )
 
+export const original_setTimeout = globalThis.setTimeout
+
+export const patch_builtin = new Function(`
+  // Substitute some builtin functions: fetch, setTimeout, Math.random to be
+  // able to patch them in tests
+
+  const originals = {
+    random: Math.random,
+    fetch: globalThis.fetch,
+    setTimeout: globalThis.setTimeout,
+  }
+
+  const patched = {}
+
+  const patch = (obj, name) => {
+    originals[name] = obj[name]
+    obj[name] = (...args) => patched[name] == null
+      ? originals[name](...args)
+      : patched[name](...args)
+  }
+
+  patch(globalThis, 'fetch')
+  patch(globalThis, 'setTimeout')
+  patch(Math, 'random')
+
+  return (name, fn) => {
+    patched[name] = fn
+  }
+`)()
+
 export const parse_modules = (entry, modules) => 
   load_modules(entry, module_name => modules[module_name])