Fix NavMenuHighlightsCurrentLocation in headless mode by setting window size explictly, add SetWindowSize extension method

Author: oroztocil

src/Components/test/E2ETest/Tests/ComponentRenderingTestBase.cs

@@ -374,7 +374,7 @@ public void CanUseJsInteropToReferenceElements()
     [Fact]
     public void CanUseFocusExtensionToFocusElement()
     {
-        Browser.Manage().Window.Size = new System.Drawing.Size(100, 300);
+        Browser.SetWindowSize(100, 300);
         var appElement = Browser.MountTestComponent<ElementFocusComponent>();
 
         // y scroll position before click
@@ -408,7 +408,7 @@ public void CanUseFocusExtensionToFocusElement()
     [Fact]
     public void CanUseFocusExtensionToFocusSvgElement()
     {
-        Browser.Manage().Window.Size = new System.Drawing.Size(100, 300);
+        Browser.SetWindowSize(100, 300);
         var appElement = Browser.MountTestComponent<SvgFocusComponent>();
 
         var buttonElement = appElement.FindElement(By.Id("focus-button"));
@@ -430,7 +430,7 @@ public void CanUseFocusExtensionToFocusSvgElement()
     [Fact]
     public void CanUseFocusExtensionToFocusElementPreventScroll()
     {
-        Browser.Manage().Window.Size = new System.Drawing.Size(600, 600);
+        Browser.SetWindowSize(600, 600);
         var appElement = Browser.MountTestComponent<ElementFocusComponent>();
 
         var buttonElement = Browser.Exists(By.Id("focus-button-prevented"));

src/Components/test/E2ETest/Tests/StandaloneAppTest.cs

@@ -44,6 +44,12 @@ public void NavMenuHighlightsCurrentLocation()
         var activeNavLinksSelector = By.CssSelector(".sidebar a.active");
         var mainHeaderSelector = By.TagName("h1");
 
+        // The sidebar is hidden if the screen is too narrow.
+        // Without setting the window size explicitly, visibility-sensitive properties
+        // such as IWebElement.Text can return empty strings, causing assertions to fail.
+        // In particular, this happens in the headless mode (used when running without debugger).
+        Browser.SetWindowSize(1920, 1080);
+
         // Verify we start at home, with the home link highlighted
         Assert.Equal("Hello, world!", Browser.Exists(mainHeaderSelector).Text);
         Assert.Collection(Browser.FindElements(activeNavLinksSelector),

src/Shared/E2ETesting/WebDriverExtensions.cs

@@ -51,4 +51,11 @@ private static bool ShouldIgnore(LogEntry entry)
 
         return false;
     }
+
+    public static void SetWindowSize(this IWebDriver driver, int width, int height)
+    {
+        ArgumentNullException.ThrowIfNull(driver);
+
+        driver.Manage().Window.Size = new System.Drawing.Size(width, height);
+    }
 }