cmd/pkgserver: implement JS test DSL and runner

cmd/pkgserver/ui/static/test.ts

@@ -1,8 +1,127 @@
+// =============================================================================
+// DSL
+
+type TestTree = { name: string } & (TestGroup | Test);
+type TestGroup = { children: TestTree[] };
+type Test = { test: (TestController) => void };
+
+let TESTS: ({ name: string } & TestGroup)[] = [];
+
+export function suite(name: string, children: TestTree[]) {
+    checkDuplicates(name, children)
+    TESTS.push({ name, children });
+}
+
+export function context(name: string, children: TestTree[]): TestTree {
+    checkDuplicates(name, children)
+    return { name, children };
+}
+export const group = context;
+
+export function test(name: string, test: (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 {}
+
+class TestController {
+    #logBuf: string[];
+    #failed: boolean;
+
+    constructor() {
+        this.#logBuf = [];
+        this.#failed = false;
+    }
+
+    fail() {
+        this.#failed = true;
+    }
+
+    failed(): boolean {
+        return this.#failed;
+    }
+
+    failNow(): never {
+        this.fail();
+        throw new FailNowSentinel();
+    }
+
+    log(message: string) {
+        this.#logBuf.push(message);
+    }
+
+    error(message: string) {
+        this.log(message);
+        this.fail();
+    }
+
+    fatal(message: string): never {
+        this.log(message);
+        this.failNow();
+    }
+
+    getLog(): string {
+        return this.#logBuf.join("\n");
+    }
+}
+
+// =============================================================================
+// Execution
+
 export interface TestResult {
     success: boolean;
     output: string;
 }
 
+function runTests(reporter: Reporter, parents: string[], tree: TestTree) {
+    const path = [...parents, tree.name];
+    if ("children" in tree) {
+        for (const c of tree.children) runTests(reporter, path, c);
+        return;
+    }
+    let controller = new TestController();
+    let excStr: string;
+    try {
+        tree.test(controller);
+    } catch (e) {
+        if (!(e instanceof FailNowSentinel)) {
+            controller.fail();
+            excStr = extractExceptionString(e);
+        }
+    }
+    const log = controller.getLog();
+    const output = (log && excStr) ? `${log}\n${excStr}` : `${log}${excStr ?? ''}`;
+    reporter.update(path, { success: !controller.failed(), output });
+}
+
+export function run(reporter: Reporter) {
+    for (const suite of TESTS) {
+        for (const c of suite.children) runTests(reporter, [suite.name], c);
+    }
+    reporter.finalize();
+}
+
+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 && "stack" in e)) return s;
+    // v8 (Chromium, NodeJS) include the error message, while
+    // Firefox and WebKit do not.
+    if (e.stack.includes(s)) return e.stack;
+    return `${s}\n${e.stack}`;
+}
+
 // =============================================================================
 // Reporting
 
@@ -121,13 +240,3 @@ export class DOMReporter implements Reporter {
 
     finalize() {}
 }
-
-let r = typeof document !== "undefined" ? new DOMReporter() : new StreamReporter({ writeln: console.log });
-r.update(["alien", "can walk"], { success: false, output: "assertion failed" });
-r.update(["alien", "can speak"], { success: false, output: "Uncaught ReferenceError: larynx is not defined" });
-r.update(["alien", "sleep"], { success: true, output: "" });
-r.update(["Tetromino", "generate", "tessellates"], { success: false, output: "assertion failed: 1 != 2" });
-r.update(["Tetromino", "solve", "works"], { success: true, output: "" });
-r.update(["discombobulate"], { success: false, output: "hippopotamonstrosesquippedaliophobia" });
-r.update(["recombobulate"], { success: true, output: "" });
-r.finalize();