fix: exports test

Author: nbbeeken

test/index.test.ts

@@ -2,19 +2,23 @@ import { expect } from 'chai';
 import * as bindings from '../src/index';
 
 describe('index.ts', () => {
-  it('only has one export', () => {
-    expect(Object.keys(bindings).length).to.equal(2);
+  it('only has three exports', () => {
+    expect(Object.keys(bindings).length).to.equal(3);
   });
 
   it('exports a class MongoCrypt', () => {
-    expect(bindings).to.have.property('MongoCrypt');
+    expect(bindings).to.have.property('MongoCrypt').that.is.a('function');
   });
 
   it('exposes MongoCryptContextCtor', () => {
-    expect(bindings).to.have.property('MongoCryptContextCtor');
+    expect(bindings).to.have.property('MongoCryptContextCtor').that.is.a('function');
   });
 
   it('exposes MongoCryptKMSRequestCtor', () => {
-    expect(bindings).not.to.have.property('MongoCryptKMSRequestCtor');
+    expect(bindings).not.to.have.property('MongoCryptKMSRequestCtor').that.is.a('function');
+  });
+
+  it('exports a cryptoCallbacks object', () => {
+    expect(bindings).to.have.property('cryptoCallbacks').that.is.an('object');
   });
 });