Merge pull request #2046 from plotly/fix-import-error

Fix import error

Author: alexcjohnson

CHANGELOG.md

@@ -2,6 +2,12 @@
 All notable changes to `dash` will be documented in this file.
 This project adheres to [Semantic Versioning](https://semver.org/).
 
+## [UNRELEASED]
+
+### Fixed
+
+- Fix [#2045](https://github.com/plotly/dash/issues/2045) import error when using pytest but `dash[testing]` is not installed.
+
 ## [2.4.0] - 2022-05-11
 
 ### Added

dash/testing/plugin.py

@@ -1,4 +1,6 @@
 # pylint: disable=missing-docstring,redefined-outer-name
+from typing import Any
+
 import pytest
 from .consts import SELENIUM_GRID_DEFAULT
 
@@ -13,7 +15,15 @@
     from dash.testing.browser import Browser
     from dash.testing.composite import DashComposite, DashRComposite, DashJuliaComposite
 except ImportError:
-    pass
+    # Running pytest without dash[testing] installed.
+    ThreadedRunner = Any
+    ProcessRunner = Any
+    RRunner = Any
+    JuliaRunner = Any
+    Browser = Any
+    DashComposite = Any
+    DashRComposite = Any
+    DashJuliaComposite = Any
 
 
 def pytest_addoption(parser):