refactor: use typescript strict setting (bis)

Author: darrachequesne

test/util.ts

@@ -1,11 +1,11 @@
-export function times(count: number, fn: () => void) {
+export function times(count: number, done: (err?: Error) => void) {
   let i = 0;
   return () => {
     i++;
     if (i === count) {
-      fn();
+      done();
     } else if (i > count) {
-      throw new Error(`too many calls: ${i} instead of ${count}`);
+      done(new Error(`too many calls: ${i} instead of ${count}`));
     }
   };
 }
@@ -14,6 +14,6 @@ export function sleep(duration: number) {
   return new Promise((resolve) => setTimeout(resolve, duration));
 }
 
-export function shouldNotHappen(done) {
+export function shouldNotHappen(done: (err?: Error) => void) {
   return () => done(new Error("should not happen"));
 }