Update browser.userAgent to return cached data

browser/browser_mapping.go

@@ -56,7 +56,7 @@ func mapBrowser(vu moduleVU) mapping { //nolint:funlen,cyclop
 			if err != nil {
 				return "", err
 			}
-			return b.UserAgent() //nolint:wrapcheck
+			return b.UserAgent(), nil
 		},
 		"version": func() (string, error) {
 			b, err := vu.browser()

browser/mapping_test.go

@@ -255,7 +255,7 @@ type browserAPI interface {
 	NewContext(opts goja.Value) (*common.BrowserContext, error)
 	NewPage(opts goja.Value) (*common.Page, error)
 	On(string) (bool, error)
-	UserAgent() (string, error)
+	UserAgent() string
 	Version() string
 }
 

common/browser.go

@@ -647,13 +647,8 @@ func (b *Browser) On(event string) (bool, error) {
 }
 
 // UserAgent returns the controlled browser's user agent string.
-func (b *Browser) UserAgent() (string, error) {
-	action := cdpbrowser.GetVersion()
-	_, _, _, ua, _, err := action.Do(cdp.WithExecutor(b.ctx, b.conn)) //nolint:dogsled
-	if err != nil {
-		return "", fmt.Errorf("getting browser user agent: %w", err)
-	}
-	return ua, nil
+func (b *Browser) UserAgent() string {
+	return b.version.userAgent
 }
 
 // Version returns the controlled browser's version.

tests/browser_test.go

@@ -211,8 +211,7 @@ func TestBrowserUserAgent(t *testing.T) {
 
 	// testBrowserVersion() tests the version already
 	// just look for "Headless" in UserAgent
-	ua, err := b.UserAgent()
-	require.NoError(t, err)
+	ua := b.UserAgent()
 	if prefix := "Mozilla/5.0"; !strings.HasPrefix(ua, prefix) {
 		t.Errorf("UserAgent should start with %q, but got: %q", prefix, ua)
 	}