Add integration tests for Align and Margin controls

Introduces new integration tests for Align and Margin controls in Flet, including golden images for macOS. Also refactors sunflower.py to compute seeds in State's __post_init__ method for improved initialization.

Author: FeodorFitsner

sdk/python/examples/apps/declarative/sunflower.py

@@ -23,6 +23,9 @@ class State:
     seeds_count: int = MAX_SEEDS // 2
     seeds: list[Seed] = field(default_factory=list)
 
+    def __post_init__(self):
+        self.compute_seeds()
+
     def update_seeds_count(self, new_seeds_count: int):
         self.seeds_count = new_seeds_count
         self.compute_seeds()
@@ -114,7 +117,5 @@ def main(page: ft.Page):
         ),
     )
 
-    state.compute_seeds()
-
 
 ft.run(main)

sdk/python/packages/flet/integration_tests/controls/golden/macos/align/align_inside_container.png

@@ -0,0 +1,34 @@
+import pytest
+
+import flet as ft
+import flet.testing as ftt
+
+
+@pytest.mark.asyncio(loop_scope="module")
+async def test_align_inside_stack(flet_app: ftt.FletTestApp, request):
+    flet_app.page.theme_mode = ft.ThemeMode.LIGHT
+    await flet_app.assert_control_screenshot(
+        request.node.name,
+        ft.Stack(
+            [
+                ft.Button("A", align=ft.Alignment(0, 0)),
+                ft.Button("B", align=ft.Alignment(0.9, 0.9)),
+                ft.Button("C", align=ft.Alignment.BOTTOM_LEFT),
+            ],
+            width=200,
+            height=200,
+        ),
+    )
+
+
+@pytest.mark.asyncio(loop_scope="module")
+async def test_align_inside_container(flet_app: ftt.FletTestApp, request):
+    flet_app.page.theme_mode = ft.ThemeMode.LIGHT
+    await flet_app.assert_control_screenshot(
+        request.node.name,
+        ft.Container(
+            ft.Button("B", align=ft.Alignment(0.9, 0.9)),
+            width=200,
+            height=200,
+        ),
+    )

sdk/python/packages/flet/integration_tests/controls/golden/macos/align/align_inside_stack.png

@@ -0,0 +1,28 @@
+import pytest
+
+import flet as ft
+import flet.testing as ftt
+
+
+@pytest.mark.asyncio(loop_scope="module")
+async def test_margin_around(flet_app: ftt.FletTestApp, request):
+    flet_app.page.theme_mode = ft.ThemeMode.LIGHT
+    await flet_app.assert_control_screenshot(
+        request.node.name,
+        ft.Button(
+            "Button with margin",
+            margin=ft.Margin.all(20),
+        ),
+    )
+
+
+@pytest.mark.asyncio(loop_scope="module")
+async def test_margin_bottom_right(flet_app: ftt.FletTestApp, request):
+    flet_app.page.theme_mode = ft.ThemeMode.LIGHT
+    await flet_app.assert_control_screenshot(
+        request.node.name,
+        ft.Button(
+            "Button with margin",
+            margin=ft.Margin.only(bottom=20, right=20),
+        ),
+    )