cleanup implementation, fix tests

Author: baileympearson

src/connection_string.ts

@@ -20,7 +20,7 @@ import {
 import { MongoLoggableComponent, MongoLogger, SeverityLevel } from './mongo_logger';
 import { ReadConcern, type ReadConcernLevel } from './read_concern';
 import { ReadPreference, type ReadPreferenceMode } from './read_preference';
-import { type Runtime } from './runtime_adapters';
+import { resolveRuntimeAdapters } from './runtime_adapters';
 import { ServerMonitoringMode } from './sdam/monitor';
 import type { TagSet } from './sdam/server_description';
 import {
@@ -539,12 +539,7 @@ export function parseOptions(
     }
   );
 
-  const runtime: Runtime = {
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    os: options.runtimeAdapters?.os ?? require('os')
-  };
-
-  mongoOptions.runtime = runtime;
+  mongoOptions.runtime = resolveRuntimeAdapters(options);
 
   return mongoOptions;
 }

src/mongo_client.ts

@@ -319,7 +319,11 @@ export interface MongoClientOptions extends BSONSerializeOptions, SupportedNodeC
   connectionType?: typeof Connection;
   /** @internal */
   __skipPingOnConnect?: boolean;
-  /** @experimental  */
+  /**
+   * @experimental
+   *
+   * If provided, any adapters provided will be used in place of the corresponding Node.js module.
+   */
   runtimeAdapters?: RuntimeAdapters;
 }
 

src/runtime_adapters.ts

@@ -1,14 +1,24 @@
+/* eslint-disable no-restricted-imports */
+// We squash the restricted import errors here because we are using type-only imports, which
+// do not impact the driver's actual runtime dependencies.
+
+import type * as os from 'os';
+
+import { type MongoClientOptions } from './mongo_client';
+
 /**
  * @public
  * @experimental
+ *
+ * Represents the set of dependencies that the driver uses from the [Node.js OS module](https://nodejs.org/api/os.html).
  */
-export type OsAdapter = Pick<typeof import('os'), 'platform' | 'release' | 'arch' | 'type'>;
+export type OsAdapter = Pick<typeof os, 'release' | 'platform' | 'arch' | 'type'>;
 
 /**
  * @public
  * @experimental
  *
- * This type represents the interface that the driver needs from the runtime in order to function.
+ * This type represents the set of dependencies that the driver needs from the Javascript runtime in order to function.
  */
 export interface RuntimeAdapters {
   os?: OsAdapter;
@@ -18,8 +28,21 @@ export interface RuntimeAdapters {
  * @internal
  *
  * Represents a complete, parsed set of runtime adapters.  After options parsing, all adapters
- * are always present (either using the user's provided adapter, or defaulting to Nodejs' module).
+ * are always present (either using the user's provided adapter, or defaulting to the Node.js module).
  */
 export interface Runtime {
   os: OsAdapter;
 }
+
+/**
+ * @internal
+ *
+ * Given a MongoClientOptions, this function resolves the set of runtime options, providing Nodejs implementations if
+ * not provided by in `options`, and returns a `Runtime`.
+ */
+export function resolveRuntimeAdapters(options: MongoClientOptions): Runtime {
+  return {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    os: options.runtimeAdapters?.os ?? require('os')
+  };
+}

test/tools/utils.ts

@@ -7,7 +7,6 @@ import * as path from 'node:path';
 import { EJSON } from 'bson';
 import * as BSON from 'bson';
 import { expect } from 'chai';
-import * as os from 'os';
 import * as process from 'process';
 import { Readable } from 'stream';
 import { setTimeout } from 'timers';
@@ -24,6 +23,7 @@ import {
   type TopologyOptions
 } from '../../src';
 import { OP_MSG } from '../../src/cmap/wire_protocol/constants';
+import { resolveRuntimeAdapters } from '../../src/runtime_adapters';
 import { Topology } from '../../src/sdam/topology';
 import { processTimeMS } from '../../src/utils';
 import { type TestConfiguration } from './runner/config';
@@ -607,6 +607,7 @@ export function configureMongocryptdSpawnHooks(
   };
 }
 
-export const runtime: Runtime = {
-  os
-};
+/**
+ * A `Runtime` that resolves to entirely Nodejs modules, useful when tests must provide a default `runtime` object to an API.
+ */
+export const runtime: Runtime = resolveRuntimeAdapters({});