feat(tracing): show browser console errors in the trace file

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Unreleased
 
+- **Trace shows browser console errors** — when `browser.captureConsoleErrors: true`, the JS errors collected for a test now appear in its trace file under "Console Errors", next to the steps and failure details, so a shared trace includes what the browser logged. No change when the option is off. (#130)
+
 - **Network mocking on Firefox via WebDriver BiDi** — `networkMock().stub(...)` now uses WebDriver BiDi network interception under the hood when supported by the driver (including Firefox and BiDi-enabled drivers), falling back to Chrome DevTools Protocol (CDP) for Chromium-based drivers. The existing stubbing API (`returnJson`, `returnBody`, `returnStatus`, `delay`, `clear`) works identically across Chrome and Firefox. (#196)
 
 ---

docs-site/docs/changelog.md

@@ -11,6 +11,8 @@ All notable changes to Selenium Boot are documented here.
 
 ## [Unreleased]
 
+- **Trace shows browser console errors** — when `browser.captureConsoleErrors: true`, the JS errors collected for a test now appear in its trace file under "Console Errors", next to the steps and failure details, so a shared trace includes what the browser logged. No change when the option is off. (#130)
+
 - **Network mocking on Firefox via WebDriver BiDi** — `networkMock().stub(...)` now uses WebDriver BiDi network interception under the hood when supported by the driver (including Firefox and BiDi-enabled drivers), falling back to Chrome DevTools Protocol (CDP) for Chromium-based drivers. The existing stubbing API (`returnJson`, `returnBody`, `returnStatus`, `delay`, `clear`) works identically across Chrome and Firefox. (#196)
 
 ---

src/main/java/com/seleniumboot/tracing/TraceRecorder.java

@@ -28,6 +28,7 @@
  *   <li>Named step timeline — each step logged via {@code StepLogger} as a clickable block</li>
  *   <li>Per-step screenshots — click a step to reveal its screenshot</li>
  *   <li>Final-state screenshot — taken at the moment of failure</li>
+ *   <li>Browser console errors — when {@code browser.captureConsoleErrors} is on</li>
  *   <li>Error message + full stack trace</li>
  * </ul>
  *
@@ -196,6 +197,17 @@ public static String buildHtml(TestTiming timing, String testName, String finalS
             sb.append("  </div>\n</div>\n");
         }
 
+        // ── Console errors ──
+        List<String> consoleErrors = timing.getConsoleErrors();
+        if (!consoleErrors.isEmpty()) {
+            sb.append("<div class=\"section\">\n");
+            sb.append("  <div class=\"section-title\">Console Errors");
+            sb.append("  <span class=\"step-count\">(").append(consoleErrors.size()).append(")</span></div>\n");
+            sb.append("  <pre class=\"stack-trace console-errors\">");
+            for (String e : consoleErrors) sb.append(escHtml(e)).append('\n');
+            sb.append("</pre>\n</div>\n");
+        }
+
         // ── Error section ──
         if (errorMsg != null || stackTrace != null) {
             sb.append("<div class=\"section error-section\">\n");

src/test/java/com/seleniumboot/unit/TraceRecorderTest.java

@@ -186,6 +186,23 @@ public void buildHtml_escapesHtmlInErrorMessage() {
     // Helper
     // ------------------------------------------------------------------
 
+    @Test
+    public void buildHtml_rendersConsoleErrors_escaped() {
+        TestTiming t = timing("jsErrTest");
+        t.setConsoleErrors(List.of("TypeError: x is undefined", "<script>alert(1)</script>"));
+        String html = TraceRecorder.buildHtml(t, "jsErrTest", null);
+        Assert.assertTrue(html.contains("Console Errors"), "console section expected");
+        Assert.assertTrue(html.contains("TypeError: x is undefined"));
+        Assert.assertTrue(html.contains("&lt;script&gt;alert(1)&lt;/script&gt;"), "must be HTML-escaped");
+        Assert.assertFalse(html.contains("<script>alert(1)</script>"));
+    }
+
+    @Test
+    public void buildHtml_omitsConsoleSection_whenNoErrors() {
+        String html = TraceRecorder.buildHtml(timing("cleanJs"), "cleanJs", null);
+        Assert.assertFalse(html.contains("Console Errors"));
+    }
+
     private static TestTiming timing(String testName) {
         TestTiming t = new TestTiming(testName, "test-thread");
         t.setStatus("FAILED");