diff --git a/packages/core/src/generators/ast/__tests__/generate.test.mjs b/packages/core/src/generators/ast/__tests__/generate.test.mjs
index 3f2e3b224..00e88cd50 100644
--- a/packages/core/src/generators/ast/__tests__/generate.test.mjs
+++ b/packages/core/src/generators/ast/__tests__/generate.test.mjs
@@ -1,7 +1,7 @@
 import assert from 'node:assert/strict';
 import { mkdtemp, writeFile, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join, sep } from 'node:path';
 import { after, before, describe, it } from 'node:test';
 
 import { STABILITY_INDEX_URL } from '../constants.mjs';
@@ -9,12 +9,14 @@ import { processChunk } from '../generate.mjs';
 
 let dir;
 
+const toPosixPath = value => value.split(sep).join('/');
+
 // Writes `content` to `<name>` in the temp dir and returns the
 // `[path, parent]` tuple `processChunk` expects.
 const file = async (name, content) => {
   const path = join(dir, name);
   await writeFile(path, content);
-  return [path, dir];
+  return [toPosixPath(path), toPosixPath(dir)];
 };
 
 // Runs a single file through `processChunk` and returns its result entry.
diff --git a/packages/react/src/html/utils/__tests__/copying.test.mjs b/packages/react/src/html/utils/__tests__/copying.test.mjs
index 7363dcd63..b18ec2d56 100644
--- a/packages/react/src/html/utils/__tests__/copying.test.mjs
+++ b/packages/react/src/html/utils/__tests__/copying.test.mjs
@@ -118,9 +118,9 @@ describe('copyStaticAssets', () => {
     assert.strictEqual(mockLogError.mock.callCount(), 1);
 
     const logMessage = mockLogError.mock.calls[0].arguments[0];
-    assert.match(
+    assert.equal(
       logMessage,
-      /\[html-generator\] Failed to copy asset from protected-file to \/out\/protected-file: Permission denied/
+      `[html-generator] Failed to copy asset from protected-file to ${join('/out', 'protected-file')}: Permission denied`
     );
   });
 });
diff --git a/scripts/__tests__/comparators.test.mjs b/scripts/__tests__/comparators.test.mjs
index ddcde32d4..e398ae7da 100644
--- a/scripts/__tests__/comparators.test.mjs
+++ b/scripts/__tests__/comparators.test.mjs
@@ -163,10 +163,20 @@ test('comparators report added and removed output files', async t => {
   ]);
 
   assert.match(sizes, /2 files changed/);
-  assert.match(sizes, /`generator\/added\.json` \| — \| 12\.00 B/);
-  assert.match(sizes, /`generator\/removed\.json` \| 12\.00 B \| —/);
-  assert.match(objects, /`generator\/added\.json` added/);
-  assert.match(objects, /`generator\/removed\.json` removed/);
+  const added = `generator${path.sep}added.json`;
+  const removed = `generator${path.sep}removed.json`;
+  const escapeRegExp = value => value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+
+  assert.match(
+    sizes,
+    new RegExp(`\`${escapeRegExp(added)}\` \\| — \\| 12\\.00 B`)
+  );
+  assert.match(
+    sizes,
+    new RegExp(`\`${escapeRegExp(removed)}\` \\| 12\\.00 B \\| —`)
+  );
+  assert.match(objects, new RegExp(`\`${escapeRegExp(added)}\` added`));
+  assert.match(objects, new RegExp(`\`${escapeRegExp(removed)}\` removed`));
   assert.doesNotMatch(sizes, /comparison\.txt|4\.00 KB/);
   assert.doesNotMatch(objects, /comparison\.txt/);
 });