Initial Commit

packages/media/audio/audio-core/tests/purity.test.ts

@@ -0,0 +1,115 @@
+import { readdirSync, readFileSync, statSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { metrics, trace } from "@opentelemetry/api";
+import { describe, expect, it } from "@suaveplan/testing/runner";
+
+const PKG_ROOT = join(dirname(fileURLToPath(import.meta.url)), "..");
+
+// The complete set the spec's "Universal purity" requirement allows
+// in package.json `dependencies`.
+const ALLOWED_DEPENDENCIES = new Set([
+    "@opentelemetry/api",
+    "@suaveplan/error",
+    "@suaveplan/events",
+    "@suaveplan/serialize",
+    "@suaveplan/streams",
+    "@suaveplan/types",
+    "tslib",
+    "zod",
+]);
+
+// Bare-identifier globals with no legitimate use in a universal package.
+const FORBIDDEN_GLOBALS = [
+    "window",
+    "document",
+    "navigator",
+    "AudioContext",
+    "Buffer",
+];
+
+function collectDistJs(dir: string, acc: string[] = []): string[] {
+    for (const entry of readdirSync(dir)) {
+        const full = join(dir, entry);
+        if (statSync(full).isDirectory()) {
+            collectDistJs(full, acc);
+        } else if (entry.endsWith(".js")) {
+            acc.push(full);
+        }
+    }
+    return acc;
+}
+
+// Remove comments and string/template literals so import-path substrings
+// (e.g. "./process/...") and message text cannot trigger false positives.
+function stripStringsAndComments(src: string): string {
+    return src
+        .replace(/\/\*[\s\S]*?\*\//g, " ")
+        .replace(/\/\/[^\n]*/g, " ")
+        .replace(/"(?:[^"\\]|\\.)*"/g, '""')
+        .replace(/'(?:[^'\\]|\\.)*'/g, "''")
+        .replace(/`(?:[^`\\]|\\.)*`/g, "``");
+}
+
+describe("universal purity", () => {
+    it("dist references no browser or Node globals", {
+        timeout: 5000,
+    }, () => {
+        const files = collectDistJs(join(PKG_ROOT, "dist"));
+        expect(files.length).toBeGreaterThan(0);
+        const offenders: string[] = [];
+        for (const file of files) {
+            const raw = readFileSync(file, "utf8");
+            const code = stripStringsAndComments(raw);
+            for (const name of FORBIDDEN_GLOBALS) {
+                const re = new RegExp(`(?<![.\\w])${name}(?![\\w])`);
+                if (re.test(code)) offenders.push(`${file}: ${name}`);
+            }
+            // `process` is also a domain identifier here (audio "process"
+            // ops/methods), so only the Node-global access pattern — a
+            // free `process` followed by member access — is forbidden.
+            if (/(?<![.\w])process\s*\./.test(code)) {
+                offenders.push(`${file}: process global`);
+            }
+            if (/node:fs|node:path/.test(raw)) {
+                offenders.push(`${file}: node: import`);
+            }
+        }
+        expect(offenders).toEqual([]);
+    });
+
+    it("dependency set is limited to the declared workspace and zod", {
+        timeout: 5000,
+    }, () => {
+        const pkg = JSON.parse(
+            readFileSync(join(PKG_ROOT, "package.json"), "utf8")
+        ) as { dependencies?: Record<string, string> };
+        const deps = Object.keys(pkg.dependencies ?? {});
+        expect(deps.length).toBeGreaterThan(0);
+        for (const dep of deps) {
+            expect({ dep, allowed: ALLOWED_DEPENDENCIES.has(dep) }).toEqual({
+                dep,
+                allowed: true,
+            });
+        }
+    });
+
+    it("importing the package mutates no global state", {
+        timeout: 5000,
+    }, async () => {
+        // Ignore tooling/dependency internals (vitest, zod's registry);
+        // the assertion is that *this package* registers nothing global.
+        const userGlobals = (): string[] =>
+            Object.keys(globalThis)
+                .filter((k) => !k.startsWith("__"))
+                .sort();
+        const globalsBefore = userGlobals();
+        const tracerProviderBefore = trace.getTracerProvider();
+        const meterProviderBefore = metrics.getMeterProvider();
+        await import("../src/index.js");
+        // No new globals, and no global OTel provider registered at import.
+        expect(userGlobals()).toEqual(globalsBefore);
+        expect(trace.getTracerProvider()).toBe(tracerProviderBefore);
+        expect(metrics.getMeterProvider()).toBe(meterProviderBefore);
+    });
+});