test: improve error message for policy failures

PR-URL: https://github.com/nodejs/node/pull/35633
Fixes: https://github.com/nodejs/node/issues/35600
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/common/README.md

@@ -378,6 +378,11 @@ const { spawn } = require('child_process');
 spawn(...common.pwdCommand, { stdio: ['pipe'] });
 ```
 
+### `requireNoPackageJSONAbove()`
+
+Throws an `AssertionError` if a `package.json` file is in any ancestor
+directory. Such files may interfere with proper test functionality.
+
 ### `runWithInvalidFD(func)`
 
 * `func` [<Function>][]

test/common/index.js

@@ -697,6 +697,20 @@ function gcUntil(name, condition) {
   });
 }
 
+function requireNoPackageJSONAbove() {
+  let possiblePackage = path.join(__dirname, '..', 'package.json');
+  let lastPackage = null;
+  while (possiblePackage !== lastPackage) {
+    if (fs.existsSync(possiblePackage)) {
+      assert.fail(
+        'This test shouldn\'t load properties from a package.json above ' +
+        `its file location. Found package.json at ${possiblePackage}.`);
+    }
+    lastPackage = possiblePackage;
+    possiblePackage = path.join(possiblePackage, '..', '..', 'package.json');
+  }
+}
+
 const common = {
   allowGlobals,
   buildType,
@@ -736,6 +750,7 @@ const common = {
   platformTimeout,
   printSkipMessage,
   pwdCommand,
+  requireNoPackageJSONAbove,
   runWithInvalidFD,
   skip,
   skipIf32Bits,

test/parallel/test-policy-dependencies.js

@@ -3,6 +3,7 @@
 const common = require('../common');
 if (!common.hasCrypto)
   common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const fixtures = require('../common/fixtures');
 

test/parallel/test-policy-dependency-conditions.js

@@ -4,6 +4,7 @@
 const common = require('../common');
 
 if (!common.hasCrypto) common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const Manifest = require('internal/policy/manifest').Manifest;
 

test/parallel/test-policy-integrity-flag.js

@@ -3,6 +3,7 @@
 const common = require('../common');
 if (!common.hasCrypto)
   common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const fixtures = require('../common/fixtures');
 

test/parallel/test-policy-parse-integrity.js

@@ -2,6 +2,7 @@
 
 const common = require('../common');
 if (!common.hasCrypto) common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const tmpdir = require('../common/tmpdir');
 const assert = require('assert');

test/parallel/test-policy-scopes-dependencies.js

@@ -4,6 +4,7 @@
 const common = require('../common');
 
 if (!common.hasCrypto) common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const Manifest = require('internal/policy/manifest').Manifest;
 const assert = require('assert');

test/parallel/test-policy-scopes-integrity.js

@@ -4,6 +4,7 @@
 const common = require('../common');
 
 if (!common.hasCrypto) common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const Manifest = require('internal/policy/manifest').Manifest;
 const assert = require('assert');

test/parallel/test-policy-scopes.js

@@ -3,6 +3,7 @@
 const common = require('../common');
 if (!common.hasCrypto)
   common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const fixtures = require('../common/fixtures');
 

test/pummel/test-policy-integrity.js

@@ -2,6 +2,7 @@
 
 const common = require('../common');
 if (!common.hasCrypto) common.skip('missing crypto');
+common.requireNoPackageJSONAbove();
 
 const { debuglog } = require('util');
 const debug = debuglog('test');