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);
+    }
+  });
+};