fix existing tests

Author: lobsterkatie

packages/nextjs/test/config.test.ts

@@ -7,12 +7,24 @@ import {
   SentryWebpackPluginOptions,
   WebpackConfigObject,
 } from '../src/config/types';
-import {
-  CLIENT_SDK_CONFIG_FILE,
-  constructWebpackConfigFunction,
-  SentryWebpackPlugin,
-  SERVER_SDK_CONFIG_FILE,
-} from '../src/config/webpack';
+import { constructWebpackConfigFunction, SentryWebpackPlugin } from '../src/config/webpack';
+
+const SERVER_SDK_CONFIG_FILE = 'sentry.server.config.js';
+const CLIENT_SDK_CONFIG_FILE = 'sentry.client.config.js';
+
+// We use `fs.existsSync()` in `getUserConfigFile()`. When we're not testing `getUserConfigFile()` specifically, all we
+// need is for it to give us any valid answer, so make it always find what it's looking for. Since this is a core node
+// built-in, though, which jest itself uses, otherwise let it do the normal thing. Storing the real version of the
+// function also lets us restore the original when we do want to test `getUserConfigFile()`.
+const realExistsSync = jest.requireActual('fs').existsSync;
+const mockExistsSync = (path: fs.PathLike) => {
+  if ((path as string).endsWith(SERVER_SDK_CONFIG_FILE) || (path as string).endsWith(CLIENT_SDK_CONFIG_FILE)) {
+    return true;
+  }
+
+  return realExistsSync(path);
+};
+const exitsSync = jest.spyOn(fs, 'existsSync').mockImplementation(mockExistsSync);
 
 /** Mocks of the arguments passed to `withSentryConfig` */
 const userNextConfig = {
@@ -63,8 +75,13 @@ const clientWebpackConfig = {
   target: 'web',
   context: '/Users/Maisey/projects/squirrelChasingSimulator',
 };
-const serverBuildContext = { isServer: true, dev: false, buildId: 'doGsaREgReaT' };
-const clientBuildContext = { isServer: false, dev: false, buildId: 'doGsaREgReaT' };
+const baseBuildContext = {
+  dev: false,
+  buildId: 'doGsaREgReaT',
+  dir: '/Users/Maisey/projects/squirrelChasingSimulator',
+};
+const serverBuildContext = { isServer: true, ...baseBuildContext };
+const clientBuildContext = { isServer: false, ...baseBuildContext };
 
 /**
  * Derive the final values of all next config options, by first applying `withSentryConfig` and then, if it returns a