Unit testing lib Jest install and setup

src/__test__/App.test.js

@@ -0,0 +1,14 @@
+import React from "react";
+import renderer from "react-test-renderer";
+
+import App from "../App";
+//FIXME:currently, I can't run the example that is in the expo documentation
+// -> https://docs.expo.io/guides/testing-with-jest/#unit-test
+
+// NOTE: Just an toy example for verifying if Jest is running
+describe("<App />", () => {
+  it("has 1 child", () => {
+    // const tree = renderer.create(<App />).toJSON();
+    expect(1 + 1).toBe(2);
+  });
+});

src/package.json

@@ -5,7 +5,14 @@
     "android": "expo start --android",
     "ios": "expo start --ios",
     "web": "expo start --web",
-    "eject": "expo eject"
+    "eject": "expo eject",
+    "test": "jest"
+  },
+  "jest": {
+    "preset": "jest-expo",
+    "transformIgnorePatterns": [
+      "node_modules/(?!(jest-)?react-native|react-clone-referenced-element|@react-native-community|expo(nent)?|@expo(nent)?/.*|react-navigation|@react-navigation/.*|@unimodules/.*|unimodules|sentry-expo|native-base|@sentry/.*)"
+    ]
   },
   "dependencies": {
     "@expo/metro-config": "^0.1.44",
@@ -43,7 +50,9 @@
   "devDependencies": {
     "@babel/core": "^7.12.10",
     "babel-core": "^6.26.3",
-    "babel-loader": "^8.2.2"
+    "babel-loader": "^8.2.2",
+    "jest-expo": "^40.0.1",
+    "react-test-renderer": "^17.0.1"
   },
   "private": true
 }