add some validation of curtin config generated from answers

scripts/runtests.sh

@@ -1,4 +1,9 @@
 #!/bin/bash
+set -eux
 python3 -m unittest discover
-# The --foreground is important to avoid subiquity getting SIGTTOU-ed.
-timeout --foreground 60 sh -c 'LANG=C.UTF-8 PYTHONPATH=. python3 -m subiquity.cmd.tui --answers examples/answers.yaml --dry-run --machine-config examples/mwhudson.json'
+export SUBIQUITY_REPLAY_TIMESCALE=10
+for answers in examples/answers*.yaml; do
+    # The --foreground is important to avoid subiquity getting SIGTTOU-ed.
+    timeout --foreground 60 sh -c "LANG=C.UTF-8 python3 -m subiquity.cmd.tui --answers $answers --dry-run --machine-config examples/mwhudson.json"
+    python3 scripts/validate-yaml.py .subiquity/subiquity-curtin-install.conf
+done

scripts/validate-yaml.py

@@ -0,0 +1,62 @@
+#!/usr/bin/python3
+import sys
+
+import yaml
+
+
+class StorageChecker:
+
+    def __init__(self):
+        self.actions = {}
+        self.unmounted_swap_ids = set()
+
+    def _check_partition(self, action):
+        assert 'device' in action
+        assert action['device'] in self.actions
+        assert 'ptable' in self.actions[action['device']]
+
+    def _check_format(self, action):
+        assert 'volume' in action
+        assert action['volume'] in self.actions
+        if action['fstype'] == 'swap':
+            self.unmounted_swap_ids.add(action['id'])
+
+    def _check_mount(self, action):
+        assert 'device' in action
+        assert action['device'] in self.actions
+        if not action.get('path'):
+            assert self.actions[action['device']]['fstype'] == "swap"
+            self.unmounted_swap_ids.remove(action['device'])
+
+    def check(self, action):
+        assert 'type' in action
+        assert 'id' in action
+        m = getattr(self, '_check_{type}'.format(**action), None)
+        if m:
+            m(action)
+        self.actions[action['id']] = action
+
+    def final_checks(self):
+        if len(self.unmounted_swap_ids) > 0:
+            raise Exception(
+                "some swap formats had no mounts: {}".format(
+                    self.unmounted_swap_ids))
+
+
+config = yaml.safe_load(open(sys.argv[1]))
+
+
+def main():
+    storage_checker = StorageChecker()
+
+    for action in config['storage']['config']:
+        try:
+            storage_checker.check(action)
+        except Exception:
+            print('checking {} failed'.format(action))
+            raise
+
+    storage_checker.final_checks()
+
+
+main()