# Transition Testcases

## Client Configurations

Each test case should be run with following configurations with at least `2^14` validators:
1) 100% of each EL+CL combo (60?)
2) Something that roughly mimics client currently share on EL+CL

## Test Cases

### Happy Case
A mock client mines a normal PoW chain which reaches `TotalTerminalDifficulty`, CL+EL continue to finalization with live `ExecutionPayloads`.

#### Steps
* Mock client mines a terminal PoW block and propogates it to all EL clients.
* The next proposer constructs a beacon block with a `TRANSITION_BLOCK`.
* The proposer after that should build a block which builds an execution payload on top of the `TRANSITION_BLOCK`.
* So on and so forth until the chain finalizes a checkpoint that includes a non-zero `ExecutionPayload`.

#### Checks
- [ ] Verify the chain post-transition finalizes.
- [ ] Verify every CL client agrees on the head.
- [ ] Verify `execution_payload.block_hash` of a finalized checkpoint is in the canonical chain of all ELs.
- [ ] Verify all beacon clients have proposed a block with a valid `ExecutionPayload`.
- [ ] Verify `TRANSITION_BLOCK.parent` is the terminal PoW block.

### Withholding Terminal PoW Block
A mock client mines a normal PoW chain and propogates `TRANSITION_BLOCK` to a single partition in the network. After missing finalization, propogate to the rest of the network.

#### Steps

* Mock client mines up to a terminal PoW block and propogates it to all EL clients, except the terminal block.
* The mock client reveals the terminal PoW block to one partition of the network.
* There seems like three main test cases here:
* Partition $A$ where $|A| > 2n/3$ of validators and partition $B$ where $|B| < n/3$. In this case, the chain will finalize a `TRANSITION_BLOCK`. Once the terminal block is released to partition $B$, partition $B$ should begin accepting current canonical chain.
* Partition $A$ where $|A| < n/3$ of validators and partition $B$ where $|B| > 2n/3$. In this case, the chain will continue to finalize. Once the terminal block is released to partition $B$, partition $A$ and $B$ should accept a `TRANSITION_BLOCK` that builds on the terminal block.
* Partition $A$ where $|A| = n/2$ and parition $B$ where $|B| = n/2$. Similar to above, although it's not clear to me how quickly the network will resolve these issues and finalize a chain without a `TRANSITION_BLOCK`.

#### Checks

- [ ] Verify the chain does not finalize a `TRANSITION_BLOCK` before it is propogated to all partitions.
- [ ] Verify the chain finalizes after the `TRANSITION_BLOCK` is propogated to all partitions.
- [ ] Verify all CL clients agree on the head.
- [ ] Verify `execution_payload.block_hash` of a finalized checkpoint is in the canonical chain of all EL clients.
- [ ] Verify all CL clients have proposed a block with a valid `ExecutionPayload`.

### Multiple Terminal PoW Blocks
A mock client mines a normal PoW chain and propogates multiple `TRANSITION_BLOCK`s to different partitions of the network.

#### Steps

* Mock client mines up to a terminal PoW block and propogates it to all EL clients, except the terminal block.
* The mock client reveals a distinct terminal PoW block for each partition of the network.
* There seems like three main test cases here are roughly the same as in the withholding test case, except it's testing that a client can let go of it's current terminal block and accept a new one.

#### Checks

- [ ] Verify the chain finalizes.
- [ ] Verify all CL clients agree on the head.
- [ ] Verify `execution_payload.block_hash` of a finalized checkpoint is in the canonical chain of all EL clients.
- [ ] Verify all beacon clients have proposed a block with a valid `ExecutionPayload`.

### Syncing Test Case(s) (?)
I don't quite understand this [test case](https://hackmd.io/@n0ble/Hk8X_hvwY#Hive):
> passing a terminal block point while syncing; then CL must go back and validate terminal block conditions, finalized and not yet finalized cases should be covered; similar to the case when block is withheld

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Another one: CL+EL both fully partitioned with miners on both and after a few epochs reveal one partition to the other