Add jest for unit tests

.gitea/workflows/tests.yaml

@@ -21,3 +21,5 @@ jobs:
         run: nix develop --impure --command bash -c 'export HOME=$PWD; yarn run lint'
       - name: typecheck
         run: nix develop --impure --command bash -c 'export HOME=$PWD; yarn tsc --noEmit'
+      - name: test
+        run: nix develop --impure --command bash -c 'export HOME=$PWD; yarn run test'

package.json

@@ -10,8 +10,14 @@
     "lint": "eslint . --ext .js,.ts,.tsx",
     "lint:fix": "eslint . --ext .ts,.tsx --fix",
     "start:dev": "ENVFILE=.env.development react-native start",
-    "start:prod": "ENVFILE=.env.production react-native start"
+    "start:prod": "ENVFILE=.env.production react-native start",
+    "test": "jest"
   },
+  "jest": {
+    "preset": "jest-expo",
+    "transformIgnorePatterns": [
+    "node_modules/(?!((jest-)?react-native|@react-native(-community)?)|expo(nent)?|@expo(nent)?/.*|@expo-google-fonts/.*|react-navigation|@react-navigation/.*|@unimodules/.*|unimodules|sentry-expo|native-base|react-native-svg)"
+  ]},
   "dependencies": {
     "@types/react": "~18.2.14",
     "@typescript-eslint/eslint-plugin": "^6.17.0",
@@ -22,13 +28,16 @@
     "eslint-plugin-react-native": "^4.1.0",
     "expo": "~49.0.15",
     "expo-status-bar": "~1.6.0",
+    "jest": "^29.2.1",
+    "jest-expo": "~49.0.0",
     "react": "18.2.0",
     "react-native": "0.72.6",
     "react-native-dotenv": "^3.4.9",
     "typescript": "^5.3.3"
   },
   "devDependencies": {
-    "@babel/core": "^7.20.0"
+    "@babel/core": "^7.20.0",
+    "@types/jest": "^29.5.11"
   },
   "private": true
 }

tests/App.test.js

@@ -0,0 +1,12 @@
+import React from "react";
+import renderer from "react-test-renderer";
+
+import App from "./App";
+
+
+describe("<App />", () => {
+    it("has 1 child", () => {
+        const tree = renderer.create(<App />).toJSON();
+        expect(tree.children.length).toBe(1);
+    });
+});