Set up unit testing for engines

engines/execution-controller.ts

@@ -106,7 +106,7 @@ class ExecutionController<RS> {
    * @param param0.interval Interval between two execution steps
    * @param param0.onResult Callback called with result on each execution step
    */
-  async executeAll({ interval, onResult }: ExecuteAllArgs<RS>) {
+  executeAll({ interval, onResult }: ExecuteAllArgs<RS>) {
     // Clear paused state
     this._isPaused = false;
 

engines/test-utils.ts

@@ -0,0 +1,48 @@
+import { readFileSync } from "fs";
+import { resolve } from "path";
+import ExecutionController from "./execution-controller";
+import { LanguageEngine } from "./types";
+
+/**
+ * Read the entire contents of a test program.
+ * @param dirname Absolute path to directory containing program
+ * @param name Name of TXT file, without extension
+ * @returns Contents of file, as a \n-delimited string
+ */
+export const readTestProgram = (dirname: string, name: string): string => {
+  const path = resolve(dirname, name + ".txt");
+  return readFileSync(path, { encoding: "utf8" }).toString();
+};
+
+/**
+ * Run code on language engine and return final result.
+ * If error thrown, promise rejects with the error.
+ * @param engine Engine to use for execution
+ * @param code Source code to execute
+ * @param input STDIN input for execution
+ * @returns Final execution result object
+ */
+export const executeProgram = async <T>(
+  engine: LanguageEngine<T>,
+  code: string,
+  input: string = ""
+): Promise<{ output: string; rendererState: T }> => {
+  const controller = new ExecutionController(engine);
+  controller.prepare(code, input);
+  return new Promise((resolve, reject) => {
+    try {
+      let output = "";
+      controller.executeAll({
+        interval: 0,
+        onResult: (res) => {
+          if (res.output) output += res.output;
+          if (res.nextStepLocation == null) {
+            resolve({ output, rendererState: res.rendererState });
+          }
+        },
+      });
+    } catch (error) {
+      reject(error);
+    }
+  });
+};

jest.config.js

@@ -0,0 +1,17 @@
+const nextJest = require("next/jest");
+
+const createJestConfig = nextJest({
+  // Provide the path to your Next.js app to load next.config.js and .env files in your test environment
+  dir: "./",
+});
+
+// Add any custom config to be passed to Jest
+const customJestConfig = {
+  // setupFilesAfterEnv: ["<rootDir>/jest.setup.js"],
+  // if using TypeScript with a baseUrl set to the root directory then you need the below for alias' to work
+  // moduleDirectories: ["node_modules", "<rootDir>/"],
+  testEnvironment: "jest-environment-node",
+};
+
+// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
+module.exports = createJestConfig(customJestConfig);

package.json

@@ -6,6 +6,7 @@
     "build": "next build",
     "start": "next start",
     "lint": "next lint",
+    "test": "jest",
     "dev:worker": "webpack -c worker-pack/webpack.dev.js --watch",
     "build:worker": "webpack -c worker-pack/webpack.prod.js"
   },
@@ -19,10 +20,12 @@
     "react-mosaic-component": "^5.0.0"
   },
   "devDependencies": {
+    "@types/jest": "^27.4.0",
     "@types/node": "16.11.11",
     "@types/react": "17.0.37",
     "eslint": "8.4.0",
     "eslint-config-next": "12.0.7",
+    "jest": "^27.4.7",
     "ts-loader": "^9.2.6",
     "typescript": "4.5.2",
     "webpack": "^5.65.0",