As of December 2020, I'm using detox 17.14.3 with Expo 39.0.5 and I've managed to solve this issue without needing to use a standalone build. Patch and explanation provided below.
It turns out that detox-expo-helpers is overriding an environment variable (specifically SIMCTL_CHILD_DYLD_INSERT_LIBRARIES) to specify the path to the ExpoDetoxHook framework (provided by the expo-detox-hook package). Well, that update to the environment now happens too late in the cycle. It takes place when running Detox's reloadApp, but by then, Detox has started up Jest which has workers running with their own copy of process.env. Workers get a copy of process.env at the time of creation, and they are not shared with the parent process, so the changes this library makes to environment variables are not reflected inside Jest workers. The hook framework is not available to the running application, and so the Detox is stuck waiting for a ready signal that doesn't come.
Detox's launchApp for iOS simulator uses SIMCTL_CHILD_DYLD_INSERT_LIBRARIES to specify it's own library, but because the environment vars are isolated in the worker, it does not see the change this package makes. To solve this, I modified this library to expose the changes to process.env as a separate exported function, and then I call that much earlier in the test lifecycle to ensure it is set before any workers are started. Here is a patch compatible with patch-package.
# file patches/detox-expo-helpers+0.6.0.patch
diff --git a/node_modules/detox-expo-helpers/index.js b/node_modules/detox-expo-helpers/index.js
index 864493b..3147a55 100644
--- a/node_modules/detox-expo-helpers/index.js
+++ b/node_modules/detox-expo-helpers/index.js
@@ -45,7 +45,16 @@ function resetEnvDyldVar(oldEnvVar) {
}
}
-const reloadApp = async (params) => {
+let initialized = false;
+let detoxVersion;
+let oldEnvVar;
+const init = () => {
+ if (initialized) {
+ return;
+ }
+
+ initialized = true;
+
if (!fs.existsSync(expoDetoxHookPackageJsonPath)) {
throw new Error("expo-detox-hook is not installed in this directory. You should declare it in package.json and run `npm install`");
}
@@ -56,12 +65,16 @@ const reloadApp = async (params) => {
throw new Error ("expo-detox-hook is not installed in your osx Library. Run `npm install -g expo-detox-cli && expotox clean-framework-cache && expotox build-framework-cache` to fix this.");
}
- const detoxVersion = getDetoxVersion();
- const oldEnvVar = process.env.SIMCTL_CHILD_DYLD_INSERT_LIBRARIES;
+ detoxVersion = getDetoxVersion();
+ oldEnvVar = process.env.SIMCTL_CHILD_DYLD_INSERT_LIBRARIES;
if (semver.gte(detoxVersion, '9.0.6')) {
process.env.SIMCTL_CHILD_DYLD_INSERT_LIBRARIES = expoDetoxHookFrameworkPath;
}
+}
+
+const reloadApp = async (params) => {
+ init();
const formattedBlacklistArg = await blacklistCmdlineFormat(params && params.urlBlacklist);
const url = await getAppUrl();
@@ -121,5 +134,6 @@ module.exports = {
getAppUrl,
getAppHttpUrl,
blacklistLiveReloadUrl,
+ init,
reloadApp,
};
With that in place, I modified my e2e/environment.js file to look like the following. The addition is the initExpo call. When it runs this early in the test lifecycle, the environment is modified before any workers are started, and as a result, calls to reloadApp no longer wait indefinitely.
/* eslint-disable import/no-extraneous-dependencies */
const { init: initExpo } = require('detox-expo-helpers');
const { DetoxCircusEnvironment, SpecReporter, WorkerAssignReporter } = require('detox/runners/jest-circus');
class CustomDetoxEnvironment extends DetoxCircusEnvironment {
constructor(config) {
super(config);
initExpo();
// Can be safely removed, if you are content with the default value (=300000ms)
this.initTimeout = 300000;
// This takes care of generating status logs on a per-spec basis. By default, Jest only reports at file-level.
// This is strictly optional.
this.registerListeners({
SpecReporter,
WorkerAssignReporter,
});
}
}
module.exports = CustomDetoxEnvironment;
