boot: allow plans with None bootloader

subiquity/common/filesystem/boot.py

@@ -142,6 +142,14 @@ class MountBootEfiPlan(MakeBootDevicePlan):
         manipulator._mount_esp(self.part)
 
 
+@attr.s(auto_attribs=True)
+class NoOpBootPlan(MakeBootDevicePlan):
+    """Do nothing, successfully"""
+
+    def apply(self, manipulator):
+        pass
+
+
 @attr.s(auto_attribs=True)
 class MultiStepPlan(MakeBootDevicePlan):
     """Execute several MakeBootDevicePlans in sequence."""
@@ -296,6 +304,8 @@ def get_boot_device_plan(device, resize_partition=None):
         return get_boot_device_plan_uefi(device, resize_partition)
     if bl == Bootloader.PREP:
         return get_boot_device_plan_prep(device, resize_partition)
+    if bl == Bootloader.NONE:
+        return NoOpBootPlan()
     raise Exception(f'unexpected bootloader {bl} here')
 
 

subiquity/server/controllers/tests/test_filesystem.py

@@ -139,7 +139,7 @@ class TestLayout(TestCase):
 
 
 bootloaders_and_ptables = [(bl, pt)
-                           for bl in list(Bootloader) if bl != Bootloader.NONE
+                           for bl in list(Bootloader)
                            for pt in ('gpt', 'msdos', 'vtoc')]