test(testkit): cover the env-driven E2E ports instead of a fixed list

The ports test parsed a hard-coded array that no longer exists. It now
runs the script on a fake host whose fuser finds nothing, and checks the
default ports, the per-runner override, the rejection of a non-numeric
setting, and that the workflow picks the ports before freeing them.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MRtGG9ARfqqhma3t85Ro2u

packages/testkit/src/e2e-ports.test.ts

@@ -1,9 +1,12 @@
-import { readFileSync } from "node:fs";
+import { execFileSync } from "node:child_process";
+import { chmodSync, mkdtempSync, readFileSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
 import path from "node:path";
 import { describe, expect, it } from "vitest";
 
 const repoRoot = path.resolve(import.meta.dirname, "../../..");
 const scriptPath = path.join(repoRoot, "scripts/free-e2e-ports.sh");
+const script = readFileSync(scriptPath, "utf8");
 const playwrightWorkflow = readFileSync(
   path.join(repoRoot, ".github/workflows/playwright.yml"),
   "utf8",
@@ -15,20 +18,62 @@ function portsFromShellArray(source: string, name: string): number[] {
   return [...match![1].matchAll(/\b(\d+)\b/g)].map(([, port]) => Number(port));
 }
 
+/** Runs the script on a fake Linux host whose fuser never finds a listener, so nothing is killed. */
+function runScript(env: Record<string, string>): { status: number; output: string } {
+  const fakeBin = mkdtempSync(path.join(tmpdir(), "evoo-e2e-ports-"));
+  for (const [name, body] of [
+    ["uname", "echo Linux"],
+    ["fuser", "exit 1"],
+  ] as const) {
+    const file = path.join(fakeBin, name);
+    writeFileSync(file, `#!/usr/bin/env bash\n${body}\n`);
+    chmodSync(file, 0o755);
+  }
+  try {
+    const output = execFileSync("bash", [scriptPath], {
+      env: { PATH: `${fakeBin}:${process.env.PATH}`, ...env },
+      encoding: "utf8",
+      stdio: ["ignore", "pipe", "pipe"],
+    });
+    return { status: 0, output };
+  } catch (error) {
+    const failure = error as { status: number; stdout: string; stderr: string };
+    return { status: failure.status, output: `${failure.stdout}${failure.stderr}` };
+  }
+}
+
+function announcedPorts(output: string): number[] {
+  const match = output.match(/E2E ports \(([^)]*)\)/);
+  expect(match, "announced E2E ports").toBeTruthy();
+  return match![1].split(" ").map(Number);
+}
+
 describe("free-e2e-ports.sh", () => {
-  const script = readFileSync(scriptPath, "utf8");
-
-  it("declares dedicated E2E ports separate from live dev ports", () => {
+  it("keeps the live dev ports apart from the default E2E ports", () => {
     const livePorts = portsFromShellArray(script, "LIVE_PORTS");
-    const e2ePorts = portsFromShellArray(script, "E2E_PORTS");
-
     expect(livePorts).toEqual([3100, 5173]);
+
+    const run = runScript({});
+    expect(run.status).toBe(0);
+    const e2ePorts = announcedPorts(run.output);
     expect(e2ePorts).toEqual([3110, 3111, 5180, 4321]);
     for (const livePort of livePorts) {
       expect(e2ePorts).not.toContain(livePort);
     }
   });
 
+  it("follows the harness port settings so runners on one host never touch each other", () => {
+    const run = runScript({ API_PORT: "3310", WEB_PORT: "5380", WWW_PORT: "4521" });
+    expect(run.status).toBe(0);
+    expect(announcedPorts(run.output)).toEqual([3310, 3311, 5380, 4521]);
+  });
+
+  it("refuses a port setting that is not a number", () => {
+    const run = runScript({ API_PORT: "abc" });
+    expect(run.status).toBe(1);
+    expect(run.output).toContain("API_PORT must be a port number");
+  });
+
   it("uses fuser and skips non-Linux hosts", () => {
     expect(script).toContain('fuser -k "$spec"');
     expect(script).toContain('uname -s)" != "Linux"');
@@ -44,4 +89,13 @@ describe("free-e2e-ports.sh", () => {
       playwrightWorkflow.indexOf("Run marketing homepage E2E"),
     );
   });
+
+  it("gets its ports from the workflow step that picks them per runner", () => {
+    const pickStep = playwrightWorkflow.indexOf("Pick E2E ports for this runner");
+    expect(pickStep).toBeGreaterThan(-1);
+    expect(pickStep).toBeLessThan(playwrightWorkflow.indexOf("free-e2e-ports.sh"));
+    for (const setting of ["API_PORT=", "WEB_PORT=", "WWW_PORT="]) {
+      expect(playwrightWorkflow).toContain(setting);
+    }
+  });
 });