SCP Gherkin Tests

gherkin/scp/publisher/start_instance.feature

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+Feature: Publisher Start Instance
+  The shared publisher is responsible for launching every SCP instance.
+  When an instance starts, it broadcasts the StartInstance message to each rollup that
+  appears in the XTRequest and starts a local timeout for the decision phase.
+
+  Background:
+    Given there is a shared publisher "SP"
+    And there is a chain "1" with sequencer "A"
+    And there is a chain "2" with sequencer "B"
+    And there is a chain "3" with sequencer "C"
+    And there is a chain "4" with sequencer "D"
+
+  @publisher @scp @start-instance
+  Scenario: Broadcasts StartInstance to all participating sequencers
+    When the shared publisher "SP" starts an instance:
+      """
+      instance_id: 0x1
+      period_id: 7
+      sequence_number: 3
+      xtrequest:
+        1: [tx1_1, tx1_2]
+        2: [tx2]
+        3: [tx3]
+      """
+    Then sequencers "A,B,C" should receive StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 7
+      sequence_number: 3
+      xtrequest:
+        1: [tx1_1, tx1_2]
+        2: [tx2]
+        3: [tx3]
+      """
+    And a timer for instance "0x1" should start at the shared publisher
+
+  @publisher @scp @start-instance
+  Scenario: Notifies only chains referenced in the XTRequest
+    When the shared publisher "SP" starts an instance:
+      """
+      instance_id: 0x2
+      period_id: 8
+      sequence_number: 4
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    Then sequencer "A" should receive StartInstance with instance ID "0x2"
+    And sequencer "B" should receive StartInstance with instance ID "0x2"
+    And sequencer "C" should not receive StartInstance for instance "0x2"
+    And sequencer "D" should not receive StartInstance for instance "0x2"

gherkin/scp/publisher/timeout.feature

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+Feature: Publisher Timeout
+  The shared publisher starts a local timer when it launches an SCP instance.
+  If the timer expires before a decision is sent, it must reject the instance and notify
+  every participant. Once a decision is broadcast, any subsequent timeout should be ignored.
+
+  Background:
+    Given there is a shared publisher "SP"
+    And there is a chain "1" with sequencer "A"
+    And there is a chain "2" with sequencer "B"
+
+  @publisher @scp @timeout
+  Scenario: Rejects instance when the timer expires before all votes are received
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x8
+      period_id: 14
+      sequence_number: 10
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x8   |
+      | chain_id    | 1     |
+      | vote        | true  |
+    When the timer for the shared publisher "SP" expires for instance "0x8"
+    Then the shared publisher "SP" should publish Decided with:
+      | field       | value |
+      | instance_id | 0x8   |
+      | decision    | false |
+    And the shared publisher "SP" should mark the instance "0x8" as rejected
+
+  @publisher @scp @timeout
+  Scenario Outline: Ignores timer expiry after a decision has been published
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x9
+      period_id: 15
+      sequence_number: 11
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And the shared publisher "SP" has already published Decided for instance "0x9" with decision "<decision>"
+    When the timer for the shared publisher "SP" expires for instance "0x9"
+    Then no additional Decided message should be sent for instance "0x9"
+
+    Examples:
+      | decision |
+      | true     |
+      | false    |

gherkin/scp/publisher/votes.feature

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+Feature: Publisher Vote Processing
+  The shared publisher collects votes from the sequencers that were included in the XTRequest.
+  It keeps one vote per chain, rejects invalid senders, and finalizes the instance once the
+  voting rules are satisfied.
+
+  Background:
+    Given there is a shared publisher "SP"
+    And there is a chain "1" with sequencer "A"
+    And there is a chain "2" with sequencer "B"
+    And there is a chain "3" with sequencer "C"
+
+  @publisher @scp @votes
+  Scenario: Accepts instance after collecting all positive votes
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x3
+      period_id: 9
+      sequence_number: 5
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    When sequencer "A" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x3   |
+      | chain_id    | 1     |
+      | vote        | true  |
+    And sequencer "B" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x3   |
+      | chain_id    | 2     |
+      | vote        | true  |
+    Then the shared publisher "SP" should publish Decided with:
+      | field       | value |
+      | instance_id | 0x3   |
+      | decision    | true  |
+    And the shared publisher "SP" should mark the instance "0x3" as accepted
+
+  @publisher @scp @votes
+  Scenario: Rejects instance immediately when a vote is false
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x4
+      period_id: 10
+      sequence_number: 6
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+        3: [tx3]
+      """
+    When sequencer "C" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x4   |
+      | chain_id    | 3     |
+      | vote        | false |
+    Then the shared publisher "SP" should publish Decided with:
+      | field       | value |
+      | instance_id | 0x4   |
+      | decision    | false |
+    And the shared publisher "SP" should mark the instance "0x4" as rejected
+    And subsequent votes for instance "0x4" should be ignored
+
+  @publisher @scp @votes
+  Scenario: Errors when receiving a duplicated vote from the same chain
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x5
+      period_id: 11
+      sequence_number: 7
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" has already published Vote with:
+      | field       | value |
+      | instance_id | 0x5   |
+      | chain_id    | 1     |
+      | vote        | true  |
+    When sequencer "A" publishes another Vote for instance "0x5"
+    Then an error occurs:
+      """
+      duplicated vote for chain 1
+      """
+
+  @publisher @scp @votes
+  Scenario: Rejects votes from chains that are not part of the instance
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x6
+      period_id: 12
+      sequence_number: 8
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    When sequencer "C" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x6   |
+      | chain_id    | 3     |
+      | vote        | true  |
+    Then an error occurs:
+      """
+      vote from non-participant chain
+      """
+
+  @publisher @scp @votes
+  Scenario: Ignores votes that arrive after the instance has been decided
+    Given the shared publisher "SP" started an instance:
+      """
+      instance_id: 0x7
+      period_id: 13
+      sequence_number: 9
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" has already published Vote with:
+      | field       | value |
+      | instance_id | 0x7   |
+      | chain_id    | 1     |
+      | vote        | false |
+    And the shared publisher "SP" has already published Decided for instance "0x7" with decision "false"
+    When sequencer "B" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x7   |
+      | chain_id    | 2     |
+      | vote        | true  |
+    Then no additional Decided message should be sent for instance "0x7"

gherkin/scp/sequencer/decision.feature

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+Feature: Sequencer Decision
+  On the sequencer perspective, an instance terminates in two cases:
+  - when it sends a rejection vote (either due simulation failure or timeout)
+  - when it receives a decision from the SP
+  If the instance is decided as rejected, the sequencer should not include its transactions in a block.
+  Else, it should include the transactions along with the created mailbox.putInbox ones.
+  Note that the shared publisher can only send a decision true if all sequencers have voted true.
+  Thus, receiving a decision true without having voted true is an invalid protocol state.
+
+  Background:
+    Given there is a chain "1" with sequencer "A"
+    And there is a chain "2" with sequencer "B"
+
+  @sequencer @scp @decision
+  Scenario: Rejects instance upon simulation failure
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And the execution engine simulates "tx1" and returns an error other than "Read miss"
+    When sequencer "A" publishes Vote with:
+      | field       | value |
+      | instance_id | 0x1   |
+      | chain_id    | 1     |
+      | vote        | false |
+    Then sequencer "A" should mark the instance "0x1" as rejected
+
+  @sequencer @scp @decision
+  Scenario: Rejects instance when decision is false
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    When sequencer "A" receives Decided for instance "0x1" with decision "false"
+    Then sequencer "A" should mark the instance "0x1" as rejected
+
+  @sequencer @scp @decision
+  Scenario: Errors when decision true arrives without a prior vote
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" has not published a Vote for instance "0x1"
+    When sequencer "A" receives Decided for instance "0x1" with decision "true"
+    Then an error occurs:
+      """
+      decision true but no vote sent is an impossible state
+      """
+
+  @sequencer @scp @decision
+  Scenario: Errors when decision true contradicts a prior false vote
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" previously published Vote with:
+      | field       | value |
+      | instance_id | 0x1   |
+      | chain_id    | 1     |
+      | vote        | false |
+    When sequencer "A" receives Decided for instance "0x1" with decision "true"
+    Then an error occurs:
+      """
+      decision true but previous vote was false is an impossible state
+      """
+
+  @sequencer @scp @decision
+  Scenario: Finalizes instance when decision is received from SP
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And the execution engine simulates "tx1" and returns success
+    And sequencer "A" previously published Vote with:
+      | field       | value |
+      | instance_id | 0x1   |
+      | chain_id    | 1     |
+      | vote        | true  |
+    When sequencer "A" receives Decided for instance "0x1" with decision <decision>
+    Then sequencer "A" should mark the instance "0x1" as <outcome>
+    Examples:
+      | decision | outcome   |
+      | true     | accepted  |
+      | false    | rejected  |
+
+  @sequencer @scp @decision
+  Scenario: Raises error when a decided instance receives a second decision
+    Given sequencer "A" receives StartInstance:
+      """
+      instance_id: 0x1
+      period_id: 2
+      sequence_number: 2
+      xtrequest:
+        1: [tx1]
+        2: [tx2]
+      """
+    And sequencer "A" receives Decided for instance "0x1" with decision "false"
+    When sequencer "A" later receives Decided for instance "0x1" with decision "true"
+    Then an error occurs:
+      """
+      instance already decided
+      """