fix(utils::assertion): change to use named fallback error

Author: hasezoey

docs/guides/error-warning-details.md

@@ -75,3 +75,10 @@ This Error gets thrown when this package runs on an unsupported architecture by
 ## BinaryNotFoundError
 
 *extend documentation*
+
+## AssertionFallbackError
+
+Example: `Assert failed - no custom error`
+
+Details:  
+This Error gets thrown when no custom error to `assertion` is given, this should never happen

packages/mongodb-memory-server-core/src/util/__tests__/utils.test.ts

@@ -3,7 +3,11 @@ import { ChildProcess } from 'child_process';
 import * as utils from '../utils';
 import * as tmp from 'tmp';
 import { resolve } from 'path';
-import { BinaryNotFoundError, InsufficientPermissionsError } from '../errors';
+import {
+  AssertionFallbackError,
+  BinaryNotFoundError,
+  InsufficientPermissionsError,
+} from '../errors';
 import { assertIsError } from '../../__tests__/testUtils/test_utils';
 
 tmp.setGracefulCleanup();
@@ -47,13 +51,18 @@ describe('utils', () => {
   });
 
   describe('assertion', () => {
+    it('should run without error', () => {
+      expect(utils.assertion(true)).toStrictEqual(void 0);
+    });
+
     it('should throw default error if none provided', () => {
-      expect.assertions(1);
+      expect.assertions(2);
       try {
         utils.assertion(false);
         fail('Expected Assertion to Throw');
       } catch (err) {
         assertIsError(err);
+        expect(err).toBeInstanceOf(AssertionFallbackError);
         expect(err.message).toMatchSnapshot();
       }
     });

packages/mongodb-memory-server-core/src/util/errors.ts

@@ -115,3 +115,12 @@ export class BinaryNotFoundError extends Error {
     super(`No Binary at path "${path}" was found! (ENOENT)`);
   }
 }
+
+/**
+ * Custom Fallback Error for "utils.assertion", it is a named/custom Error to confuse less in the stacktrace
+ */
+export class AssertionFallbackError extends Error {
+  constructor() {
+    super('Assert failed - no custom error');
+  }
+}

packages/mongodb-memory-server-core/src/util/utils.ts

@@ -3,7 +3,11 @@ import { ChildProcess } from 'child_process';
 import { AutomaticAuth } from '../MongoMemoryServer';
 import { promises as fspromises, Stats, constants } from 'fs';
 import { LinuxOS } from './getos';
-import { BinaryNotFoundError, InsufficientPermissionsError } from './errors';
+import {
+  AssertionFallbackError,
+  BinaryNotFoundError,
+  InsufficientPermissionsError,
+} from './errors';
 
 const log = debug('MongoMS:utils');
 
@@ -76,7 +80,7 @@ export function isNullOrUndefined(val: unknown): val is null | undefined {
  */
 export function assertion(cond: unknown, error?: Error): asserts cond {
   if (!cond) {
-    throw error ?? new Error('Assert failed - no custom error');
+    throw error ?? new AssertionFallbackError();
   }
 }