Make empty web test discovery version-stable

.github/workflows/ci.yml

@@ -300,11 +300,7 @@ jobs:
         run: bun run typecheck
 
       - name: Web tests
-        # Explicit sorted file list: bun discovers test files in filesystem
-        # readdir order, which differs between Linux runners and local macOS,
-        # so an unpinned run exercises a file order no developer can
-        # reproduce. Sorted order makes CI failures replayable locally.
-        run: bun test $(ls tests/*.test.ts tests/*.test.tsx | sort)
+        run: bun run test
 
   # Checks for in-app React webviews (currently the diff viewer; more cmux React
   # surfaces will live alongside it).

tests/test_ci_self_hosted_guard.sh

@@ -839,6 +839,68 @@ check_web_db_behavior_tests() {
   echo "PASS: web DB behavior tests run through the discovery runner"
 }
 
+check_web_test_runner_wiring() {
+  local runner="$ROOT_DIR/web/scripts/run-tests.sh"
+  if [[ ! -f "$runner" ]]; then
+    echo "FAIL: shared web test runner is missing"
+    exit 1
+  fi
+
+  if ! grep -Fq '"test": "bash scripts/run-tests.sh"' "$ROOT_DIR/web/package.json"; then
+    echo "FAIL: web/package.json must expose the shared web test runner"
+    exit 1
+  fi
+
+  if ! awk '
+    /^  web-typecheck:/ { in_job=1; next }
+    in_job && /^  [^[:space:]#][^:]*:[[:space:]]*(#.*)?$/ { in_job=0 }
+    in_job && /- name: Web tests/ { in_step=1; next }
+    in_step && /^[[:space:]]*- name:/ { in_step=0 }
+    in_step && /^[[:space:]]*run:[[:space:]]*bun run test([[:space:]]|$)/ { saw_shared_runner=1 }
+    END { exit !saw_shared_runner }
+  ' "$CI_FILE"; then
+    echo "FAIL: web-typecheck must use the shared local web test runner"
+    exit 1
+  fi
+
+  echo "PASS: CI and local web tests use the shared runner"
+}
+
+check_web_test_runner_behavior() {
+  local fixture_dir fixture_runner args_log expected_args
+  fixture_dir="$(mktemp -d)"
+  fixture_runner="$fixture_dir/web/scripts/run-tests.sh"
+  args_log="$fixture_dir/bun-args.log"
+  mkdir -p "$fixture_dir/web/scripts" "$fixture_dir/bin"
+  cp "$ROOT_DIR/web/scripts/run-tests.sh" "$fixture_runner"
+
+  cat > "$fixture_dir/bin/bun" <<'EOF'
+#!/usr/bin/env bash
+set -euo pipefail
+printf '%s\n' "$@" > "$CMUX_WEB_TEST_RUNNER_ARGS_LOG"
+EOF
+  chmod +x "$fixture_dir/bin/bun"
+
+  if ! PATH="$fixture_dir/bin:/usr/bin:/bin" \
+    CMUX_WEB_TEST_RUNNER_ARGS_LOG="$args_log" \
+    /bin/bash "$fixture_runner"; then
+    rm -rf "$fixture_dir"
+    echo "FAIL: shared web test runner default discovery should execute"
+    exit 1
+  fi
+
+  expected_args=$'test\n--isolate'
+  if [[ "$(cat "$args_log")" != "$expected_args" ]]; then
+    echo "FAIL: shared web test runner must preserve Bun's default discovery with isolation"
+    cat "$args_log"
+    rm -rf "$fixture_dir"
+    exit 1
+  fi
+
+  rm -rf "$fixture_dir"
+  echo "PASS: shared web test runner delegates default discovery to Bun with isolation"
+}
+
 check_tmux_terminal_nightly_isolation() {
   check_macos_runner "$TMUX_CORPUS_FILE" "terminal-nightly"
 
@@ -1027,4 +1089,6 @@ check_gui_smoke_unsupported_launch_handling
 check_no_ci_xctest_skips
 check_no_ci_swift_package_skips
 check_web_db_behavior_tests
+check_web_test_runner_wiring
+check_web_test_runner_behavior
 check_tmux_terminal_nightly_isolation

web/package.json

@@ -25,7 +25,7 @@
     "db:up": "bash scripts/db-local.sh up",
     "db:url": "bash scripts/db-local.sh url",
     "start": "next start",
-    "test": "bun test",
+    "test": "bash scripts/run-tests.sh",
     "test:db:behavior": "bash scripts/run-db-behavior-tests.sh",
     "typecheck": "tsgo --noEmit",
     "lint": "eslint"

web/scripts/run-tests.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+WEB_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$WEB_ROOT"
+
+default_test_file_exists() {
+  while IFS= read -r -d '' file; do
+    case "$file" in
+      *.js | *.jsx | *.ts | *.tsx | *.mjs | *.cjs | *.mts | *.cts) ;;
+      *) continue ;;
+    esac
+    case "${file##*/}" in
+      *".test"* | *"_test_"* | *".spec"* | *"_spec_"*) return 0 ;;
+    esac
+  done < <(
+    find . \
+      \( -path "./node_modules" -o -path "./.next" \) -prune \
+      -o -type f -print0
+  )
+  return 1
+}
+
+if (( $# == 0 )) && ! default_test_file_exists; then
+  echo "cmux web test runner found no test files" >&2
+  exit 1
+fi
+
+exec bun test --isolate "$@"

web/tests/web-test-runner-isolation.test.ts

@@ -0,0 +1,122 @@
+import { expect, test } from "bun:test";
+import { spawnSync } from "node:child_process";
+import {
+  copyFileSync,
+  mkdirSync,
+  mkdtempSync,
+  rmSync,
+  writeFileSync,
+} from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const webRoot = fileURLToPath(new URL("..", import.meta.url));
+const runnerPath = fileURLToPath(
+  new URL("../scripts/run-tests.sh", import.meta.url),
+);
+const fixtureTestSource = `
+import { test } from "bun:test";
+test("fixture runs", () => {});
+`;
+
+test("shared web test runner isolates module mocks across files", () => {
+  const result = runChild(
+    process.execPath,
+    [
+      "run",
+      "test",
+      "--",
+      "--randomize",
+      "--seed=1",
+      "tests/feedback-route.test.ts",
+      "tests/founders-welcome-route.test.ts",
+    ],
+    webRoot,
+  );
+
+  if (result.status !== 0) {
+    throw new Error(
+      `shared web test runner leaked module state:\n${result.output}`,
+    );
+  }
+  expect(result.output).toContain("tests/feedback-route.test.ts:");
+  expect(result.output).toContain("tests/founders-welcome-route.test.ts:");
+  expect(result.output).toContain("0 fail");
+});
+
+test("shared web test runner preserves recursive default discovery", () => {
+  const fixtureRoot = createRunnerFixture();
+  try {
+    mkdirSync(join(fixtureRoot, "tests", "nested"), { recursive: true });
+    writeFileSync(
+      join(fixtureRoot, "tests", "top-level.test.ts"),
+      fixtureTestSource,
+    );
+    writeFileSync(
+      join(fixtureRoot, "tests", "nested", "nested.test.ts"),
+      fixtureTestSource,
+    );
+
+    const result = runChild(
+      "/bin/bash",
+      ["scripts/run-tests.sh"],
+      fixtureRoot,
+    );
+    if (result.status !== 0) {
+      throw new Error(
+        `shared web test runner skipped recursive discovery:\n${result.output}`,
+      );
+    }
+    expect(result.output).toContain("tests/top-level.test.ts:");
+    expect(result.output).toContain("tests/nested/nested.test.ts:");
+  } finally {
+    rmSync(fixtureRoot, { recursive: true, force: true });
+  }
+});
+
+test("shared web test runner fails when default discovery finds no tests", () => {
+  const fixtureRoot = createRunnerFixture();
+  try {
+    mkdirSync(join(fixtureRoot, "tests"));
+    const result = runChild(
+      "/bin/bash",
+      ["scripts/run-tests.sh"],
+      fixtureRoot,
+    );
+    expect(result.status).not.toBe(0);
+    expect(result.output).toContain(
+      "cmux web test runner found no test files",
+    );
+  } finally {
+    rmSync(fixtureRoot, { recursive: true, force: true });
+  }
+});
+
+function createRunnerFixture(): string {
+  const fixtureRoot = mkdtempSync(join(tmpdir(), "cmux-web-test-runner-"));
+  mkdirSync(join(fixtureRoot, "scripts"));
+  copyFileSync(runnerPath, join(fixtureRoot, "scripts", "run-tests.sh"));
+  return fixtureRoot;
+}
+
+function runChild(
+  command: string,
+  args: string[],
+  cwd: string,
+): { status: number | null; output: string } {
+  const result = spawnSync(command, args, {
+    cwd,
+    encoding: "utf8",
+    timeout: 30_000,
+    killSignal: "SIGKILL",
+  });
+  const output = [result.stdout, result.stderr].join("\n");
+
+  if (result.error) {
+    throw new Error(
+      `shared web test runner did not finish: ${result.error.message}\n${output}`,
+    );
+  }
+  return { status: result.status, output };
+}