Add Jest for testing

.eslintrc

@@ -16,6 +16,7 @@
         "flowtype",
         "fp",
         "import",
+        "jest",
         "jsx-a11y",
         "react",
     ],
@@ -23,6 +24,7 @@
         "airbnb",
         "plugin:fp/recommended",
         "plugin:flowtype/recommended",
+        "plugin:jest/recommended",
     ],
     "settings": {
         "react": {
@@ -39,7 +41,7 @@
         "import/no-unresolved": "off",
         "indent": ["error", 4],
         "max-nested-callbacks": ["error", 1],
-        "no-underscore-dangle": ["error", { "allow": ["__INIT_MATERIAL_UI__"] }],
+        "no-underscore-dangle": "error",
         "quotes": ["error", "double", { "avoidEscape": false }],
         "react/jsx-indent": ["error", 4, { checkAttributes: false, indentLogicalExpressions: true }],
         "react/jsx-indent-props": ["error", 4],

.gitignore

@@ -58,8 +58,8 @@ typings/
 .env
 
 # NextJS files
-app/build
-app/.next
+.next
+build
 
 # OS X junk
 .DS_Store

app/babel.config.js → babel.config.js

@@ -12,10 +12,10 @@ module.exports = (api) => {
         [
             "module-resolver", {
                 alias: {
-                    components: "./app/components",
-                    lib: "./app/lib",
-                    pages: "./app/pages",
-                    styles: "./app/styles",
+                    components: "./components",
+                    lib: "./lib",
+                    pages: "./pages",
+                    styles: "./styles",
                 },
             },
         ],

jest.config.js

+module.exports = {
+    moduleFileExtensions: ["js", "jsx"],
+    testMatch: ["**/tests/**/*.test.js?(x)"],
+    testPathIgnorePatterns: ["<rootDir>/build/", "<rootDir>/node_modules/"],
+}

app/lib/getPageContext.js → lib/createPageContext.js

+import theme from "styles/theme"
 import { SheetsRegistry } from "jss"
-import { createMuiTheme, createGenerateClassName } from "@material-ui/core/styles"
-
-// A theme with custom primary and secondary color.
-// It's optional.
-const theme = createMuiTheme({
-    typography: {
-        useNextVariants: true,
-    },
-})
+import { createGenerateClassName } from "@material-ui/core/styles"
 
 function createPageContext() {
     return {
@@ -21,17 +14,4 @@ function createPageContext() {
     }
 }
 
-export default function getPageContext() {
-    // Make sure to create a new context for every server-side request so that data
-    // isn't shared between connections (which would be bad).
-    if (!process.browser) {
-        return createPageContext()
-    }
-
-    // Reuse context on the client-side.
-    if (!global.__INIT_MATERIAL_UI__) {
-        global.__INIT_MATERIAL_UI__ = createPageContext()
-    }
-
-    return global.__INIT_MATERIAL_UI__
-}
+export default createPageContext

lib/getPageContext.js

+import createPageContext from "lib/createPageContext"
+
+let pageContext
+
+export default function getPageContext() {
+    // Make sure to create a new context for every server-side request so that data
+    // isn't shared between connections (which would be bad).
+    if (!process.browser) {
+        return createPageContext()
+    }
+
+    // Reuse context on the client-side.
+    if (!pageContext) {
+        pageContext = createPageContext()
+    }
+
+    return pageContext
+}

package.json

@@ -11,12 +11,13 @@
     "keywords": [],
     "license": "AGPL 3",
     "scripts": {
-        "build": "next build app",
-        "start": "npm run build && env NODE_ENV=production node server.js",
-        "dev": "nodemon --ignore app/ server.js",
+        "build": "next build",
+        "dev": "nodemon --watch server.js server.js",
+        "prod": "npm run build && env NODE_ENV=production node server.js",
         "style:check": "eslint -c .eslintrc --ext .js,.jsx --ignore-path .gitignore .",
         "style:format": "npm run style:check -- --fix",
-        "style:rules": "eslint --print-config .eslintrc"
+        "style:rules": "eslint --print-config .eslintrc",
+        "test": "jest -c jest.config.js"
     },
     "dependencies": {
         "@material-ui/core": "^3.9.3",
@@ -42,6 +43,7 @@
         "@babel/plugin-proposal-pipeline-operator": "^7.3.2",
         "@babel/preset-flow": "^7.0.0",
         "babel-eslint": "^10.0.1",
+        "babel-jest": "^24.8.0",
         "babel-plugin-flow-react-proptypes": "^25.1.0",
         "babel-plugin-module-resolver": "^3.2.0",
         "babel-plugin-wrap-in-js": "^1.1.1",
@@ -50,8 +52,10 @@
         "eslint-plugin-flowtype": "^3.7.0",
         "eslint-plugin-fp": "^2.3.0",
         "eslint-plugin-import": "^2.17.2",
+        "eslint-plugin-jest": "^22.5.1",
         "eslint-plugin-jsx-a11y": "^6.2.1",
         "eslint-plugin-react": "^7.13.0",
+        "jest": "^24.8.0",
         "nodemon": "^1.19.0"
     }
 }

server.js

@@ -5,7 +5,7 @@ const cookieParser = require("cookie-parser")
 const path = require("path")
 
 const dev = process.env.NODE_ENV !== "production"
-const app = next({ dev, dir: "./app" })
+const app = next({ dev })
 const handle = app.getRequestHandler()
 const port = parseInt(process.env.PORT, 10) || 9001
 

styles/theme.js

+import { createMuiTheme } from "@material-ui/core/styles"
+
+const theme = createMuiTheme({
+    typography: {
+        useNextVariants: true,
+    },
+})
+
+export default theme

tests/lib/getPageContext.test.js

+/* eslint-env jest */
+
+import getPageContext from "./../../lib/getPageContext"
+
+test("it works", () => {
+    const pageContext = getPageContext()
+    return expect(pageContext).toBe(3)
+})