Add tests

jest.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};

package.json

@@ -5,13 +5,19 @@
   "author": "juusaw",
   "license": "MIT",
   "dependencies": {
-    "@types/graphql": "^14.0.7",
     "apollo-server": "^2.4.0",
     "graphql": "^14.1.1",
     "ts-node": "^8.0.2",
     "typescript": "^3.3.3"
   },
   "scripts": {
-    "start": "ts-node src/index.ts"
+    "start": "ts-node src/index.ts",
+    "test": "jest"
+  },
+  "devDependencies": {
+    "@types/graphql": "^14.0.7",
+    "@types/jest": "^24.0.5",
+    "jest": "^24.1.0",
+    "ts-jest": "^23.10.5"
   }
 }

test/dice.test.ts

@@ -0,0 +1,13 @@
+import * as dice from '../src/dice'
+
+test('Parser', () => {
+  const cases = [
+    { string: '2d6', result: [[2, 6]] },
+    { string: '1d6+1', result: [[1, 6], [1, 1]] },
+    { string: '0d6+1', result: [[0, 6], [1, 1]] },
+    { string: '-2d20+5', result: [[-2, 20], [5, 1]] },
+    { string: '3d8-10', result: [[3, 8], [-10, 1]] },
+  ]
+  cases.forEach(({ string, result }) =>
+    expect(dice.parseDice(string)).toEqual(result))
+})