Add mobile platform capability planning

tests/test_platforms.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+import unittest
+
+from ampbrowser.platforms import capability_for, normalize_platform
+
+
+class PlatformsTest(unittest.TestCase):
+    def test_android_tor_is_managed_setup_capable(self) -> None:
+        capability = capability_for("tor", "android")
+
+        self.assertEqual("android", capability.platform)
+        self.assertEqual("planned", capability.manage)
+        self.assertTrue(capability.can_manage_setup)
+
+    def test_ios_tor_is_foreground_only(self) -> None:
+        capability = capability_for("tor", "ios")
+
+        self.assertEqual("foreground-only", capability.manage)
+        self.assertTrue(capability.can_manage_setup)
+        self.assertIn("foreground", capability.note)
+
+    def test_unknown_platform_is_rejected(self) -> None:
+        with self.assertRaises(ValueError):
+            normalize_platform("watch")
+
+
+if __name__ == "__main__":
+    unittest.main()