test: add coverage for inheritance re: #7045

lib/cast/date.js

@@ -4,7 +4,7 @@ const assert = require('assert');
 
 module.exports = function castDate(value) {
   // Support empty string because of empty form values. Originally introduced
-  // in https://github.com/Automattic/mongoose/commit/efc72a1898fc3c33a319d915b8c5463a22938dfe 
+  // in https://github.com/Automattic/mongoose/commit/efc72a1898fc3c33a319d915b8c5463a22938dfe
   if (value == null || value === '') {
     return null;
   }

lib/schema/objectid.js

@@ -101,10 +101,11 @@ ObjectId._cast = castObjectId;
  *
  * ####Example:
  *
- *     // Make Mongoose only try to cast strings
+ *     // Make Mongoose only try to cast length 24 strings. By default, any 12
+ *     // char string is a valid ObjectId.
  *     const original = mongoose.ObjectId.cast();
  *     mongoose.ObjectId.cast(v => {
- *       assert.ok(v == null || typeof v === 'string');
+ *       assert.ok(typeof v !== 'string' || v.length === 24);
  *       return original(v);
  *     });
  *

test/schematype.cast.test.js

@@ -21,6 +21,34 @@ describe('SchemaType.cast() (gh-7045)', function() {
     Schema.Types.Date.cast(original.date);
   });
 
+  it('with inheritance', function() {
+    class CustomObjectId extends Schema.ObjectId {}
+
+    CustomObjectId.cast(v => {
+      assert.ok(v == null || (typeof v === 'string' && v.length === 24));
+      return original.objectid(v);
+    });
+
+    const objectid = new CustomObjectId('test', { suppressWarning: true });
+    const baseObjectId = new Schema.ObjectId('test', { suppressWarning: true });
+
+    let threw = false;
+    try {
+      objectid.cast('12charstring');
+    } catch (error) {
+      threw = true;
+      assert.equal(error.name, 'CastError');
+    }
+
+    objectid.cast('000000000000000000000000'); // Should not throw
+
+    // Base objectid shouldn't throw
+    baseObjectId.cast('12charstring');
+    baseObjectId.cast('000000000000000000000000');
+
+    assert.ok(threw);
+  });
+
   it('handles objectid', function() {
     Schema.ObjectId.cast(v => {
       assert.ok(v == null || typeof v === 'string');
@@ -31,7 +59,7 @@ describe('SchemaType.cast() (gh-7045)', function() {
 
     let threw = false;
     try {
-      objectid.cast(123);
+      objectid.cast({ toString: () => '000000000000000000000000' });
     } catch (error) {
       threw = true;
       assert.equal(error.name, 'CastError');