fix up comments and test

Author: nbbeeken

.gitignore

@@ -1,3 +1,4 @@
+node_modules/
 !mongodb-legacy.d.ts
 .vscode/
 *.tgz

test/tools/api.js

@@ -40,6 +40,7 @@ const asyncApi = [
   { className: 'AggregationCursor', method: 'explain', returnType: 'Promise<Document>' },
 
   // Super class of Unordered/Ordered Bulk operations
+  // This is listed here as a reference for completeness, but it is tested manually
   // { className: 'BulkOperationBase', method: 'execute', returnType: 'Promise<BulkWriteResult>' },
   { className: 'OrderedBulkOperation', method: 'execute', returnType: 'Promise<BulkWriteResult>' },
   { className: 'UnorderedBulkOperation', method: 'execute', returnType: 'Promise<BulkWriteResult>' },
@@ -112,6 +113,7 @@ const asyncApi = [
   { className: 'MongoClient', method: 'close', returnType: 'Promise<void>' },
   { className: 'MongoClient', method: 'connect', returnType: 'Promise<this>' },
   // Manually test the static version of connect
+  // This is listed here as a reference for completeness, but it is tested manually
   // { className: 'MongoClient', method: 'static connect', returnType: 'Promise<this>' },
 ];
 

test/unit/utils.test.js

@@ -45,9 +45,25 @@ describe('utils.js', () => {
 
       it('should not modify a rejection error promise', async () => {
         class MyError extends Error {}
-        const rejection = Promise.reject(new MyError());
+        const driverError = Object.freeze(new MyError());
+        const rejection = Promise.reject(driverError);
         const thrownError = await maybeCallback(rejection, null).catch(error => error);
-        expect(thrownError).to.be.instanceOf(MyError);
+        expect(thrownError).to.be.equal(driverError);
+      });
+
+      it('should not modify a rejection error when passed to callback', done => {
+        class MyError extends Error {}
+        const driverError = Object.freeze(new MyError());
+        const rejection = Promise.reject(driverError);
+        maybeCallback(rejection, error => {
+          try {
+            expect(error).to.exist;
+            expect(error).to.equal(driverError);
+            done();
+          } catch (assertionError) {
+            done(assertionError);
+          }
+        });
       });
     });