Add themed NavigationBar integration tests for macOS

Renamed navigation_bar.png to basic.png and added new golden images for themed NavigationBar states. Updated test_navigation_bar.py to include separate tests for basic and themed NavigationBar, verifying appearance under different theme settings and user interactions.

Author: InesaFitsner

…/macos/navigation_bar/navigation_bar.png …ls/golden/macos/navigation_bar/basic.pngsdk/python/packages/flet/integration_tests/controls/golden/macos/navigation_bar/navigation_bar.png renamed to sdk/python/packages/flet/integration_tests/controls/golden/macos/navigation_bar/basic.png sdk/python/packages/flet/integration_tests/controls/golden/macos/navigation_bar/navigation_bar.png renamed to sdk/python/packages/flet/integration_tests/controls/golden/macos/navigation_bar/basic.png

@@ -1,11 +1,18 @@
 import pytest
+import pytest_asyncio
 
 import flet as ft
 import flet.testing as ftt
 
 
-@pytest.mark.asyncio(loop_scope="module")
-async def test_navigation_bar(flet_app: ftt.FletTestApp, request):
+# Create a new flet_app instance for each test method
+@pytest_asyncio.fixture(scope="function", autouse=True)
+def flet_app(flet_app_function):
+    return flet_app_function
+
+
+@pytest.mark.asyncio(loop_scope="function")
+async def test_basic(flet_app: ftt.FletTestApp, request):
     await flet_app.assert_control_screenshot(
         request.node.name,
         ft.NavigationBar(
@@ -20,3 +27,72 @@ async def test_navigation_bar(flet_app: ftt.FletTestApp, request):
             ]
         ),
     )
+
+
+@pytest.mark.asyncio(loop_scope="function")
+async def test_theme(flet_app: ftt.FletTestApp):
+    flet_app.page.theme = ft.Theme(
+        navigation_bar_theme=ft.NavigationBarTheme(
+            bgcolor=ft.Colors.GREEN_200,
+            shadow_color=ft.Colors.ORANGE_500,
+            elevation=50,
+            indicator_color=ft.Colors.GREEN,
+            overlay_color=ft.Colors.YELLOW_300,
+            height=200,
+            label_text_style=ft.TextStyle(color=ft.Colors.ORANGE_900, size=20),
+            indicator_shape=ft.RoundedRectangleBorder(
+                radius=ft.BorderRadius.all(10),
+                side=ft.BorderSide(color=ft.Colors.PURPLE, width=3),
+            ),
+            label_behavior=ft.NavigationBarLabelBehavior.ONLY_SHOW_SELECTED,
+            label_padding=ft.Padding.all(20),
+        )
+    )
+
+    flet_app.page.enable_screenshots = True
+    flet_app.page.window.width = 400
+    flet_app.page.window.height = 600
+
+    scr_1 = ft.Screenshot(
+        ft.NavigationBar(
+            key="nb",
+            elevation=100,
+            destinations=[
+                ft.NavigationBarDestination(icon=ft.Icons.EXPLORE, label="Explore"),
+                ft.NavigationBarDestination(key="add", icon=ft.Icon(ft.Icons.ADD)),
+                ft.NavigationBarDestination(
+                    icon=ft.Icons.PHONE_ENABLED,
+                    label="Explore",
+                ),
+            ],
+        )
+    )
+    flet_app.page.add(scr_1)
+    flet_app.page.update()
+    await flet_app.tester.pump_and_settle()
+
+    flet_app.assert_screenshot(
+        "theme_1",
+        await scr_1.capture(pixel_ratio=flet_app.screenshots_pixel_ratio),
+    )
+
+    # hover to check overlay color
+    add = await flet_app.tester.find_by_key("add")
+    assert add.count == 1
+    await flet_app.tester.mouse_hover(add)
+    await flet_app.tester.pump_and_settle()
+
+    flet_app.assert_screenshot(
+        "theme_2",
+        await scr_1.capture(pixel_ratio=flet_app.screenshots_pixel_ratio),
+    )
+
+    # click to check label behaviour
+    await flet_app.tester.tap(add)
+    flet_app.page.update()
+    await flet_app.tester.pump_and_settle()
+
+    flet_app.assert_screenshot(
+        "theme_3",
+        await scr_1.capture(pixel_ratio=flet_app.screenshots_pixel_ratio),
+    )