TODO: consider dom sandbox for testing ui (see long desc)

see https://discord.com/channels/1388415325036609617/1458088018232479824/1484195713347879012

cmd/pkgserver/ui.go

@@ -29,6 +29,10 @@ func serveStaticContent(w http.ResponseWriter, r *http.Request) {
 		http.ServeFileFS(w, r, content, "ui/static/test.js")
 	case "/static/test.css":
 		http.ServeFileFS(w, r, content, "ui/static/test.css")
+	case "/static/all_tests.js":
+		http.ServeFileFS(w, r, content, "ui/static/all_tests.js")
+	case "/static/test_tests.js":
+		http.ServeFileFS(w, r, content, "ui/static/test_tests.js")
 	default:
 		http.NotFound(w, r)
 

cmd/pkgserver/ui/static/all_tests.ts

@@ -0,0 +1 @@
+import "./test_tests.js";

cmd/pkgserver/ui/static/run_tests.ts

@@ -0,0 +1,7 @@
+#!/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 { run, StreamReporter } from "./test.js";
+run(new StreamReporter({ writeln: console.log }));

cmd/pkgserver/ui/static/test.scss

@@ -21,6 +21,9 @@ details.test-node {
 p.test-desc {
     margin: 0 0 0 1rem;
     padding: 2px 0;
+    > pre {
+        margin: 0;
+    }
 }
 
 .italic {

cmd/pkgserver/ui/static/test.ts

@@ -1,12 +1,129 @@
+// =============================================================================
+// DSL
+
+type TestTree = TestGroup | Test;
+type TestGroup = { name: string, children: TestTree[] };
+type Test = { name: string, 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 {}
+
+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();
+    }
+
+    getLog(): string[] {
+        return this.#logs;
+    }
+}
+
+// =============================================================================
+// Execution
+
 export interface TestResult {
     success: boolean;
-    output: string;
+    logs: string[];
+}
+
+export function run(reporter: Reporter) {
+    reporter.register(TESTS);
+    for (const suite of TESTS) {
+        for (const c of suite.children) runTests(reporter, [suite.name], c);
+    }
+    reporter.finalize();
+}
+
+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.getLog() });
+}
+
+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.startsWith(s)) return e.stack;
+    return `${s}\n${e.stack}`;
 }
 
 // =============================================================================
 // Reporting
 
 export interface Reporter {
+    register(suites: TestGroup[]): void
     update(path: string[], result: TestResult): void;
     finalize(): void;
 }
@@ -30,6 +147,8 @@ export class StreamReporter implements Reporter {
         this.counts = { successes: 0, failures: 0 };
     }
 
+    register(suites: TestGroup[]) {}
+
     update(path: string[], result: TestResult) {
         if (path.length === 0) throw new RangeError("path is empty");
         const pathStr = path.join(SEP);
@@ -59,16 +178,10 @@ export class StreamReporter implements Reporter {
 
         for (const [path, tests] of pathMap) {
             if (tests.length === 1) {
-                const t = tests[0];
-                const pathStr = path ? `${path}${SEP}` : "";
-                const output = t.output ? `: ${t.output}` : "";
-                this.stream.writeln(`${pathStr}${t.name}${output}`);
+                this.#writeOutput(tests[0], path ? `${path}${SEP}` : "", false);
             } else {
                 this.stream.writeln(path);
-                for (const t of tests) {
-                    const output = t.output ? `: ${t.output}` : "";
-                    this.stream.writeln(`  - ${t.name}${output}`);
-                }
+                for (const t of tests) this.#writeOutput(t, "  - ", true);
             }
         }
 
@@ -76,9 +189,28 @@ export class StreamReporter implements Reporter {
         const { successes, failures } = this.counts;
         this.stream.writeln(`${successes} succeeded, ${failures} failed`);
     }
+
+    #writeOutput(test: { name: string } & TestResult, prefix: string, nested: boolean) {
+        let output = "";
+        if (test.logs.length) {
+            // Individual logs might span multiple lines, so join them together
+            // then split it again.
+            const logStr = test.logs.join("\n");
+            const lines = logStr.split("\n");
+            if (lines.length <= 1) {
+                output = `: ${logStr}`;
+            } else {
+                const padding = nested ? "      " : "  ";
+                output = ":\n" + lines.map((line) => padding + line).join("\n");
+            }
+        }
+        this.stream.writeln(`${prefix}${test.name}${output}`);
+    }
 }
 
 export class DOMReporter implements Reporter {
+    register(suites: TestGroup[]) {}
+
     update(path: string[], result: TestResult) {
         if (path.length === 0) throw new RangeError("path is empty");
         const counter = document.getElementById(result.success ? "successes" : "failures");
@@ -110,10 +242,10 @@ export class DOMReporter implements Reporter {
         }
         const p = document.createElement("p");
         p.classList.add("test-desc");
-        if (result.output) {
-            const code = document.createElement("code");
-            code.appendChild(document.createTextNode(result.output));
-            p.appendChild(code);
+        if (result.logs.length) {
+            const pre = document.createElement("pre");
+            pre.appendChild(document.createTextNode(result.logs.join("\n")));
+            p.appendChild(pre);
         } else {
             p.classList.add("italic");
             p.appendChild(document.createTextNode("No output."));
@@ -124,12 +256,30 @@ 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();
+interface GoNode {
+    name: string;
+    subtests?: GoNode[];
+}
+
+// Used to display results via `go test`, via some glue code from the Go side.
+export class GoTestReporter implements Reporter {
+    // Convert a test tree into the one expected by the Go code.
+    static serialize(node: TestTree): GoNode {
+        return {
+            name: node.name,
+            subtests: "children" in node ? node.children.map(GoTestReporter.serialize) : null,
+        };
+    }
+
+    register(suites: TestGroup[]) {
+        console.log(JSON.stringify(suites.map(GoTestReporter.serialize)));
+    }
+
+    update(path: string[], result: TestResult) {
+        console.log(JSON.stringify({ path: path, ...result }));
+    }
+
+    finalize() {
+        console.log("null");
+    }
+}

cmd/pkgserver/ui/static/test_tests.ts

@@ -0,0 +1,40 @@
+import { context, group, suite, test } from "./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");
+    }),
+]);

cmd/pkgserver/ui/test.html

@@ -18,7 +18,11 @@
 <div id="root">
 </div>
 
-<script type="module" src="./static/test.js"></script>
+<script type="module" src="./static/all_tests.js"></script>
+<script type="module">
+    import { DOMReporter, run } from "./static/test.js";
+    run(new DOMReporter());
+</script>
 </main>
 </body>
 </html>