To simulate loading .conf files from /etc/mongo/extensions in passthrough tests, we should add a configurations.yml file under the test_examples folder that will indicate what extensionOptions should be passed to each test extension. For example:

# configurations.yml
extensions:
  my-toaster-extension:
    sharedLibraryPath: "/usr/lib/mongo/extensions/toaster/my-toaster-extension.so"
    extensionOptions:
      maxToasterHeat: 5
      allowBagels: false
  blender-1.2:
    sharedLibraryPath: "/usr/lib/mongo/extensions/blender/blender-1.2.so"
    extensionOptions:
      maxSpeed: 5

With this information, we can modify load_all_extensions to parse the configurations.yml file and add new .conf files for each relevant test extension. These files should then be available during server startup and test runs, but will be destroyed after test execution is complete.