Added Error to return type of async validator (#89)

* Added Error to return type of async validator

* Split the promise validator tsd test

Author: vjau

index.d.ts

@@ -25,7 +25,7 @@ export interface FastifyBasicAuthOptions {
     req: FastifyRequest,
     reply: FastifyReply,
     done: (err?: Error) => void
-  ): void | Promise<void>;
+  ): void | Promise<void|Error>;
   authenticate?: boolean | { realm: string };
   header?: string;
 }

index.test-d.ts

@@ -12,6 +12,7 @@ import fastifyBasicAuth from '.'
 
 const app = fastify()
 
+//validation ok
 app.register(fastifyBasicAuth, {
   validate: async function validatePromise (username, password, req, reply) {
     expectType<string>(username)
@@ -23,6 +24,21 @@ app.register(fastifyBasicAuth, {
   header: 'x-forwarded-authorization'
 })
 
+//validation failure
+app.register(fastifyBasicAuth, {
+  validate: async function validatePromise (username, password, req, reply) {
+    expectType<string>(username)
+    expectType<string>(password)
+    expectType<FastifyRequest>(req)
+    expectType<FastifyReply>(reply)
+    expectType<FastifyInstance>(this)
+    return new Error("unauthorized")
+  },
+  header: 'x-forwarded-authorization'
+})
+
+
+
 app.register(fastifyBasicAuth, {
   validate: function validateCallback (username, password, req, reply, done) {
     expectType<string>(username)