SubscriptionUpgrade

1mission SubscriptionUpgrade
2use product
3use delivery
4
5title "Upgrade a customer to a higher subscription tier"
6for BillingCustomer
7
8goal
9  Let a customer move to a higher tier, charged correctly and reversibly.
10
11guarantee the customer is charged at most once per upgrade
12  because a double charge on an upgrade is a trust-breaking billing error
13  verify idempotent charge test
14
15never
16  charge a customer whose payment method is invalid
17  downgrade entitlements before the new charge settles
18
19never charge a customer whose payment method is invalid
20  because a charge that cannot settle becomes a failed payment and a refund cycle
21  verify test CanUpgrade
22
23outcome FasterUpgrades
24  "customers complete an upgrade in one step, without contacting support"
25
26metric upgrade_completion_rate
27  baseline 71%
28  target 85%
29  window 30 days after release
30
31# An executable decision: run it with `thunder run`, assert it with `thunder test`.
32decision CanUpgrade
33  inputs
34    currentTier
35    targetTier
36    paymentValid
37    outstandingBalance
38  rule noPayment
39    when paymentValid == false
40    return Blocked
41  rule owesMoney
42    when outstandingBalance > 0
43    return Blocked
44  rule higherTier
45    when targetTier > currentTier
46    return Allowed
47  default
48    return NoChange
49
50# A lifecycle: walk it with `thunder simulate`.
51lifecycle UpgradeFlow
52  state Requested
53  state Charged
54  state Active
55  state Failed
56  transition charge
57    from Requested
58    to Charged
59  transition activate
60    from Charged
61    to Active
62  transition chargeFailed
63    from Requested
64    to Failed
65  terminal Active, Failed
66
67command ChargeUpgrade
68  idempotency_key upgradeId
69  timeout 20 seconds
70on ChargeUpgradeFailed
71  compensate release entitlement hold
72
73# An outcome contract + the delivery result that measures it: `thunder outcomes`.
74outcome_contract UpgradeConversion
75  outcome FasterUpgrades
76  metric upgrade_completion_rate
77  baseline 71%
78  target 85%
79  window 30 days after release
80  owner GrowthPM
81
82result Q3Upgrades
83  measures FasterUpgrades
84  metric upgrade_completion_rate
85  value 88%
86  baseline 71%
87
88# Tests live in the file , `thunder test` runs them through the deterministic runtime.
89test CanUpgrade
90  case valid upgrade
91    given currentTier 1, targetTier 2, paymentValid true, outstandingBalance 0
92    expect Allowed
93  case invalid payment
94    given currentTier 1, targetTier 2, paymentValid false, outstandingBalance 0
95    expect Blocked
96  case owes money
97    given currentTier 1, targetTier 2, paymentValid true, outstandingBalance 25
98    expect Blocked
99  case same tier
100    given currentTier 2, targetTier 2, paymentValid true, outstandingBalance 0
101    expect NoChange
102
103test UpgradeFlow
104  scenario happy path
105    events charge, activate
106    expect Active
107    valid
108  scenario cannot activate first
109    events activate
110    invalid