fix(test-runner): undefined body crash with manual attachments (#11995)

The new (as of 1.18) `async testInfo.attach(…)` API handles this
gracefully (and is part of the reason for the new API's existence).
However, for the foreseeable future, it's still possible to manually
push onto the attachments array where we can't validate the contents
until it's too late, so this change ensures more graceful handling in
that case.

Fixes #11565

packages/playwright-test/src/reporters/base.ts

@@ -258,8 +258,8 @@ export function formatFailure(config: FullConfig, test: TestCase, options: {inde
             resultLines.push('');
           }
         } else {
-          if (attachment.contentType.startsWith('text/')) {
+          if (attachment.contentType.startsWith('text/') && attachment.body) {
-            let text = attachment.body!.toString();
+            let text = attachment.body.toString();
             if (text.length > 300)
               text = text.slice(0, 300) + '...';
             resultLines.push(colors.cyan(`    ${text}`));

tests/playwright-test/reporter-base.spec.ts

@@ -270,3 +270,22 @@ test('should print "no tests found" error', async ({ runInlineTest }) => {
   expect(result.exitCode).toBe(1);
   expect(result.output).toContain('no tests found.');
 });
+
+test('should not crash on undefined body with manual attachments', async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'a.test.js': `
+      const { test } = pwt;
+      test('one', async ({}, testInfo) => {
+        testInfo.attachments.push({
+          name: 'foo.txt',
+          body: undefined,
+          contentType: 'text/plain'
+        });
+        expect(1).toBe(2);
+      });
+    `,
+  });
+  expect(stripAnsi(result.output)).not.toContain('Error in reporter');
+  expect(result.failed).toBe(1);
+  expect(result.exitCode).toBe(1);
+});