Migrate tests to Jest (graphql#212)

Author: leebyron

.eslintrc

@@ -7,7 +7,8 @@
 
   "env": {
     "es6": true,
-    "node": true
+    "node": true,
+    "jest": true
   },
 
   "rules": {

.flowconfig

@@ -10,3 +10,5 @@
 [libs]
 
 [options]
+suppress_comment=\\(.\\|\n\\)*\\$FlowExpectError
+include_warnings=true

babel.config.js

@@ -0,0 +1,5 @@
+module.exports = api => ({
+  presets: api.env("test")
+    ? ["@babel/preset-flow"]
+    : [["@babel/preset-env", { loose: true }], "@babel/preset-flow"]
+});

flow-typed/npm/jest_v24.x.x.js

@@ -18,30 +18,15 @@
   },
   "main": "index.js",
   "typings": "index.d.ts",
-  "options": {
-    "mocha": "--require resources/mocha-bootload src/**/__tests__/**/*.js"
-  },
-  "babel": {
-    "presets": [
-      [
-        "@babel/preset-env",
-        {
-          "loose": true
-        }
-      ],
-      "@babel/preset-flow"
-    ]
-  },
   "scripts": {
     "test": "npm run lint && npm run check && npm run testonly",
     "test:ci": "npm run lint && npm run check && npm run testonly:coveralls",
     "lint": "eslint src",
     "check": "flow check",
-    "build": "babel src --ignore __tests__ --out-dir dist/ ; cp src/index.js dist/index.js.flow ; cp src/index.d.ts dist/",
+    "build": "babel src --ignore src/__tests__ --out-dir dist/ ; cp src/index.js dist/index.js.flow ; cp src/index.d.ts dist/",
     "watch": "babel resources/watch.js | node",
-    "testonly": "babel-node ./node_modules/.bin/_mocha $npm_package_options_mocha",
-    "testonly:cover": "babel-node node_modules/.bin/isparta cover --root src --report html _mocha -- $npm_package_options_mocha",
-    "testonly:coveralls": "babel-node node_modules/.bin/isparta cover --root src --report lcovonly _mocha -- $npm_package_options_mocha && cat ./coverage/lcov.info | coveralls",
+    "testonly": "jest src",
+    "testonly:coveralls": "jest src --coverage && cat ./coverage/lcov.info | coveralls",
     "preversion": ". ./resources/checkgit.sh && npm test",
     "prepublish": ". ./resources/prepublish.sh"
   },
@@ -60,12 +45,10 @@
     "@babel/preset-env": "7.7.1",
     "@babel/preset-flow": "7.0.0",
     "babel-eslint": "10.0.3",
-    "chai": "4.2.0",
     "coveralls": "3.0.7",
     "eslint": "6.6.0",
     "flow-bin": "0.112.0",
-    "isparta": "4.1.1",
-    "mocha": "6.2.2",
+    "jest": "24.9.0",
     "sane": "4.1.0"
   }
 }

package.json

@@ -28,7 +28,5 @@ cp dist/* .
 # The built output as requiring any further transformation.
 node -e "var package = require('./package.json'); \
   delete package.scripts; \
-  delete package.options; \
-  delete package.babel; \
   delete package.devDependencies; \
   require('fs').writeFileSync('package.json', JSON.stringify(package, null, 2));"

resources/mocha-bootload.js

@@ -121,12 +121,10 @@ function parseFiles(filepaths) {
 function runTests(filepaths) {
   console.log('\nRunning Tests');
 
-  return exec('mocha', [
-    '--reporter', 'progress',
-    '--require', 'resources/mocha-bootload'
-  ].concat(
-    allTests(filepaths) ? filepaths.map(srcPath) : ['src/**/__tests__/**/*.js']
-  )).catch(() => false);
+  return exec(
+    'jest',
+    allTests(filepaths) ? filepaths.map(srcPath) : ['src']
+  ).catch(() => false);
 }
 
 function lintFiles(filepaths) {

resources/prepublish.sh

@@ -4,88 +4,91 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @no-flow
+ * @flow
  */
 
-const { expect } = require('chai');
-const { describe, it } = require('mocha');
-const DataLoader = require('../');
+const DataLoader = require('..');
 
 describe('Provides descriptive error messages for API abuse', () => {
 
   it('Loader creation requires a function', () => {
     expect(() => {
+      // $FlowExpectError
       new DataLoader(); // eslint-disable-line no-new
-    }).to.throw(
+    }).toThrow(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but got: undefined.'
     );
 
     expect(() => {
+      // $FlowExpectError
       new DataLoader({}); // eslint-disable-line no-new
-    }).to.throw(
+    }).toThrow(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but got: [object Object].'
     );
   });
 
   it('Load function requires an key', () => {
-    var idLoader = new DataLoader(keys => Promise.resolve(keys));
+    const idLoader = new DataLoader(keys => Promise.resolve(keys));
 
     expect(() => {
       idLoader.load();
-    }).to.throw(
+    }).toThrow(
       'The loader.load() function must be called with a value,' +
       'but got: undefined.'
     );
 
     expect(() => {
       idLoader.load(null);
-    }).to.throw(
+    }).toThrow(
       'The loader.load() function must be called with a value,' +
       'but got: null.'
     );
 
     // Falsey values like the number 0 is acceptable
     expect(() => {
       idLoader.load(0);
-    }).not.to.throw();
+    }).not.toThrow();
   });
 
   it('LoadMany function requires a list of key', () => {
-    var idLoader = new DataLoader(keys => Promise.resolve(keys));
+    const idLoader = new DataLoader(keys => Promise.resolve(keys));
 
     expect(() => {
+      // $FlowExpectError
       idLoader.loadMany();
-    }).to.throw(
+    }).toThrow(
       'The loader.loadMany() function must be called with Array<key> ' +
       'but got: undefined.'
     );
 
     expect(() => {
+      // $FlowExpectError
       idLoader.loadMany(1, 2, 3);
-    }).to.throw(
+    }).toThrow(
       'The loader.loadMany() function must be called with Array<key> ' +
       'but got: 1.'
     );
 
     // Empty array is acceptable
     expect(() => {
       idLoader.loadMany([]);
-    }).not.to.throw();
+    }).not.toThrow();
   });
 
   it('Batch function must return a Promise, not null', async () => {
-    var badLoader = new DataLoader(() => null);
+    // $FlowExpectError
+    const badLoader = new DataLoader(() => null);
 
-    var caughtError;
+    let caughtError;
     try {
       await badLoader.load(1);
     } catch (error) {
       caughtError = error;
     }
-    expect(caughtError).to.be.instanceof(Error);
-    expect(caughtError.message).to.equal(
+    expect(caughtError).toBeInstanceOf(Error);
+    expect((caughtError: any).message).toBe(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but the function did ' +
       'not return a Promise: null.'
@@ -94,16 +97,17 @@ describe('Provides descriptive error messages for API abuse', () => {
 
   it('Batch function must return a Promise, not a value', async () => {
     // Note: this is returning the keys directly, rather than a promise to keys.
-    var badLoader = new DataLoader(keys => keys);
+    // $FlowExpectError
+    const badLoader = new DataLoader(keys => keys);
 
-    var caughtError;
+    let caughtError;
     try {
       await badLoader.load(1);
     } catch (error) {
       caughtError = error;
     }
-    expect(caughtError).to.be.instanceof(Error);
-    expect(caughtError.message).to.equal(
+    expect(caughtError).toBeInstanceOf(Error);
+    expect((caughtError: any).message).toBe(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but the function did ' +
       'not return a Promise: 1.'
@@ -112,16 +116,17 @@ describe('Provides descriptive error messages for API abuse', () => {
 
   it('Batch function must return a Promise of an Array, not null', async () => {
     // Note: this resolves to undefined
-    var badLoader = new DataLoader(() => Promise.resolve());
+    // $FlowExpectError
+    const badLoader = new DataLoader(() => Promise.resolve(undefined));
 
-    var caughtError;
+    let caughtError;
     try {
       await badLoader.load(1);
     } catch (error) {
       caughtError = error;
     }
-    expect(caughtError).to.be.instanceof(Error);
-    expect(caughtError.message).to.equal(
+    expect(caughtError).toBeInstanceOf(Error);
+    expect((caughtError: any).message).toBe(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but the function did ' +
       'not return a Promise of an Array: undefined.'
@@ -130,16 +135,16 @@ describe('Provides descriptive error messages for API abuse', () => {
 
   it('Batch function must promise an Array of correct length', async () => {
     // Note: this resolves to empty array
-    var badLoader = new DataLoader(() => Promise.resolve([]));
+    const badLoader = new DataLoader(() => Promise.resolve([]));
 
-    var caughtError;
+    let caughtError;
     try {
       await badLoader.load(1);
     } catch (error) {
       caughtError = error;
     }
-    expect(caughtError).to.be.instanceof(Error);
-    expect(caughtError.message).to.equal(
+    expect(caughtError).toBeInstanceOf(Error);
+    expect((caughtError: any).message).toBe(
       'DataLoader must be constructed with a function which accepts ' +
       'Array<key> and returns Promise<Array<value>>, but the function did ' +
       'not return a Promise of an Array of the same length as the Array ' +
@@ -155,10 +160,11 @@ describe('Provides descriptive error messages for API abuse', () => {
     }
 
     expect(() => {
-      var incompleteMap = new IncompleteMap();
-      var options = { cacheMap: incompleteMap };
-      new DataLoader(keys => keys, options); // eslint-disable-line no-new
-    }).to.throw(
+      // $FlowExpectError
+      const incompleteMap = new IncompleteMap();
+      const options = { cacheMap: incompleteMap };
+      new DataLoader(async keys => keys, options); // eslint-disable-line no-new
+    }).toThrow(
       'Custom cacheMap missing methods: set, delete, clear'
     );
   });