cmd/pkgserver/ui_test: implement DSL and runner

cmd/pkgserver/ui_test/all_tests.ts

@@ -0,0 +1,2 @@
+// Import all test files to register their test suites.
+import "./sample_tests.js";

cmd/pkgserver/ui_test/lib/cli.ts

@@ -0,0 +1,48 @@
+#!/usr/bin/env node
+
+// Many editors have terminal emulators built in, so running tests with NodeJS
+// provides faster iteration, especially for those acclimated to test-driven
+// development.
+
+import "../all_tests.js";
+import { StreamReporter, GLOBAL_REGISTRAR } from "./test.js";
+
+// TypeScript doesn't like process and Deno as their type definitions aren't
+// installed, but doesn't seem to complain if they're accessed through
+// globalThis.
+const process: any = (globalThis as any).process;
+const Deno: any = (globalThis as any).Deno;
+
+function getArgs(): string[] {
+    if (process) {
+        const [runtime, program, ...args] = process.argv;
+        return args;
+    }
+    if (Deno) return Deno.args;
+    return [];
+}
+
+function exit(code?: number): never {
+    if (Deno) Deno.exit(code);
+    if (process) process.exit(code);
+    throw `exited with code ${code ?? 0}`;
+}
+
+const args = getArgs();
+let verbose = false;
+if (args.length > 1) {
+    console.error("Too many arguments");
+    exit(1);
+}
+if (args.length === 1) {
+    if (args[0] === "-v" || args[0] === "--verbose" || args[0] === "-verbose") {
+        verbose = true;
+    } else if (args[0] !== "--") {
+        console.error(`Unknown argument '${args[0]}'`);
+        exit(1);
+    }
+}
+
+let reporter = new StreamReporter({ writeln: console.log }, verbose);
+GLOBAL_REGISTRAR.run(reporter);
+exit(reporter.succeeded() ? 0 : 1);

cmd/pkgserver/ui_test/lib/test.ts

@@ -1,8 +1,133 @@
+// =============================================================================
+// DSL
+
+type TestTree = TestGroup | Test;
+type TestGroup = { name: string; children: TestTree[] };
+type Test = { name: string; test: (t: TestController) => void };
+
+export class TestRegistrar {
+    #suites: TestGroup[];
+
+    constructor() {
+        this.#suites = [];
+    }
+
+    suite(name: string, children: TestTree[]) {
+        checkDuplicates(name, children);
+        this.#suites.push({ name, children });
+    }
+
+    run(reporter: Reporter) {
+        for (const suite of this.#suites) {
+            for (const c of suite.children) runTests(reporter, [suite.name], c);
+        }
+        reporter.finalize();
+    }
+}
+
+export let GLOBAL_REGISTRAR = new TestRegistrar();
+
+// Register a suite in the global registrar.
+export function suite(name: string, children: TestTree[]) {
+    GLOBAL_REGISTRAR.suite(name, children);
+}
+
+export function group(name: string, children: TestTree[]): TestTree {
+    checkDuplicates(name, children);
+    return { name, children };
+}
+export const context = group;
+export const describe = group;
+
+export function test(name: string, test: (t: TestController) => void): TestTree {
+    return { name, test };
+}
+
+function checkDuplicates(parent: string, names: { name: string }[]) {
+    let seen = new Set<string>();
+    for (const { name } of names) {
+        if (seen.has(name)) {
+            throw new RangeError(`duplicate name '${name}' in '${parent}'`);
+        }
+        seen.add(name);
+    }
+}
+
+class FailNowSentinel {}
+
+export class TestController {
+    logs: string[];
+    #failed: boolean;
+
+    constructor() {
+        this.logs = [];
+        this.#failed = false;
+    }
+
+    fail() {
+        this.#failed = true;
+    }
+
+    failed(): boolean {
+        return this.#failed;
+    }
+
+    failNow(): never {
+        this.fail();
+        throw new FailNowSentinel();
+    }
+
+    log(message: string) {
+        this.logs.push(message);
+    }
+
+    error(message: string) {
+        this.log(message);
+        this.fail();
+    }
+
+    fatal(message: string): never {
+        this.log(message);
+        this.failNow();
+    }
+}
+
+// =============================================================================
+// Execution
+
 export interface TestResult {
     success: boolean;
     logs: string[];
 }
 
+function runTests(reporter: Reporter, parents: string[], node: TestTree) {
+    const path = [...parents, node.name];
+    if ("children" in node) {
+        for (const c of node.children) runTests(reporter, path, c);
+        return;
+    }
+    let controller = new TestController();
+    try {
+        node.test(controller);
+    } catch (e) {
+        if (!(e instanceof FailNowSentinel)) {
+            controller.error(extractExceptionString(e));
+        }
+    }
+    reporter.update(path, { success: !controller.failed(), logs: controller.logs });
+}
+
+function extractExceptionString(e: any): string {
+    // String() instead of .toString() as null and undefined don't have
+    // properties.
+    const s = String(e);
+    if (!(e instanceof Error && e.stack)) return s;
+    // v8 (Chromium, NodeJS) includes the error message, while Firefox and
+    // WebKit do not.
+    if (e.stack.startsWith(s)) return e.stack;
+    return `${s}\n${e.stack}`;
+}
+
 // =============================================================================
 // Reporting
 
@@ -11,6 +136,24 @@ export interface Reporter {
     finalize(): void;
 }
 
+export class NoOpReporter implements Reporter {
+    results: ({ path: string[] } & TestResult)[];
+    finalized: boolean;
+
+    constructor() {
+        this.results = [];
+        this.finalized = false;
+    }
+
+    update(path: string[], result: TestResult) {
+        this.results.push({ path, ...result });
+    }
+
+    finalize() {
+        this.finalized = true;
+    }
+}
+
 export interface Stream {
     writeln(s: string): void;
 }
@@ -30,6 +173,10 @@ export class StreamReporter implements Reporter {
         this.counts = { successes: 0, failures: 0 };
     }
 
+    succeeded(): boolean {
+        return this.counts.successes > 0 && this.counts.failures === 0;
+    }
+
     update(path: string[], result: TestResult) {
         if (path.length === 0) throw new RangeError("path is empty");
         const pathStr = path.join(SEP);
@@ -145,14 +292,3 @@ export class DOMReporter implements Reporter {
 
     finalize() {}
 }
-
-let r = globalThis.document ? new DOMReporter() : new StreamReporter({ writeln: console.log });
-r.update(["alien", "can walk"], { success: false, logs: ["assertion failed"] });
-r.update(["alien", "can speak"], { success: false, logs: ["Uncaught ReferenceError: larynx is not defined"] });
-r.update(["alien", "sleep"], { success: true, logs: [] });
-r.update(["Tetromino", "generate", "tessellates"], { success: false, logs: ["assertion failed: 1 != 2"] });
-r.update(["Tetromino", "solve", "works"], { success: true, logs: [] });
-r.update(["discombobulate", "english"], { success: false, logs: ["hippopotomonstrosesquipedaliophobia\npneumonoultramicroscopicsilicovolcanoconiosis", "supercalifragilisticexpialidocious"] });
-r.update(["discombobulate", "geography"], { success: false, logs: ["Taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwhenuakitanatahu"] });
-r.update(["recombobulate"], { success: true, logs: [] });
-r.finalize();

cmd/pkgserver/ui_test/lib/ui.html

@@ -24,7 +24,11 @@
 <div id="root">
 </div>
 
-<script type="module" src="/test/lib/test.js"></script>
+<script type="module">
+    import "/test/all_tests.js";
+    import { DOMReporter, GLOBAL_REGISTRAR } from "/test/lib/test.js";
+    GLOBAL_REGISTRAR.run(new DOMReporter());
+</script>
 </main>
 </body>
 </html>

cmd/pkgserver/ui_test/sample_tests.ts

@@ -0,0 +1,64 @@
+import { NoOpReporter, TestRegistrar, context, group, suite, test } from "./lib/test.js";
+
+suite("dog", [
+    group("tail", [
+        test("wags when happy", (t) => {
+            if (0 / 0 !== Infinity / Infinity) {
+                t.fatal("undefined must not be defined");
+            }
+        }),
+        test("idle when down", (t) => {
+            t.log("test test");
+            t.error("dog whining noises go here");
+        }),
+    ]),
+    test("likes headpats", (t) => {
+        if (2 !== 2) {
+            t.error("IEEE 754 violated: 2 is NaN");
+        }
+    }),
+    context("near cat", [
+        test("is ecstatic", (t) => {
+            if (("b" + "a" + + "a" + "a").toLowerCase() === "banana") {
+                t.error("🍌🍌🍌");
+                t.error("🍌🍌🍌");
+                t.error("🍌🍌🍌");
+                t.failNow();
+            }
+        }),
+        test("playfully bites cats' tails", (t) => {
+            t.log("arf!");
+            throw new Error("nom");
+        }),
+    ]),
+]);
+
+suite("cat", [
+    test("likes headpats", (t) => {
+        t.log("meow");
+    }),
+    test("tester tester", (t) => {
+        const r = new TestRegistrar();
+        r.suite("explod", [
+            test("with yarn", (t) => {
+                t.log("YAY");
+            }),
+        ]);
+        const reporter = new NoOpReporter();
+        r.run(reporter);
+        if (!reporter.finalized) t.error(`expected reporter to have been finalized`);
+        if (reporter.results.length !== 1) {
+            t.fatal(`incorrect result count got=${reporter.results.length} want=1`);
+        }
+        const result = reporter.results[0];
+        if (!(result.path.length === 2 &&
+              result.path[0] === "explod" &&
+              result.path[1] === "with yarn")) {
+            t.error(`incorrect result path got=${result.path} want=["explod", "with yarn"]`);
+        }
+        if (!result.success) t.error(`expected test to succeed`);
+        if (!(result.logs.length === 1 && result.logs[0] === "YAY")) {
+            t.error(`incorrect result logs got=${result.logs} want=["YAY"]`);
+        }
+    }),
+]);