eth2.0-specs/tests/formats/transition

Transition testing

Transition tests to cover processing the chain across a fork boundary.

Each test case contains a post_fork key in the meta.yaml that indicates the target fork which also fixes the fork the test begins in.

Clients should assume forks happen sequentially in the following manner:

0. phase0
1. altair
2. bellatrix
3. capella
4. deneb

For example, if a test case has post_fork of altair, the test consumer should assume the test begins in phase0 and use that specification to process the initial state and any blocks up until the fork epoch. After the fork happens, the test consumer should use the specification according to the altair fork to process the remaining data.

Test case format

meta.yaml

post_fork: string              -- String name of the spec after the fork.
fork_epoch: int                -- The epoch at which the fork takes place.
fork_block: int                -- Optional. The `<index>` of the last block on the initial fork.
blocks_count: int              -- The number of blocks processed in this test.

Note: There may be a fork transition function to run at the fork_epoch. Refer to the specs for the relevant fork for further details.

pre.ssz_snappy

A SSZ-snappy encoded BeaconState according to the specification of the initial fork, the state before running the block transitions.

blocks_<index>.ssz_snappy

A series of files, with <index> in range [0, blocks_count). Blocks must be processed in order, following the main transition function (i.e. process slot and epoch transitions in between blocks as normal).

Blocks are encoded as SignedBeaconBlocks from the relevant spec version as indicated by the post_fork and fork_block data in the meta.yaml.

As blocks span fork boundaries, a fork_block number is given in the meta.yaml to help resolve which blocks belong to which fork.

The fork_block is the index in the test data of the last block of the initial fork.

To demonstrate, the following diagram shows slots with _ and blocks in those slots as x. The fork happens at the epoch delineated by the |.

x   x     x x
_ _ _ _ | _ _ _ _

The blocks_count value in the meta.yaml in this case is 4 where the fork_block value in the meta.yaml is 1. If this particular example were testing the fork from Phase 0 to Altair, blocks with indices 0, 1 represent SignedBeaconBlocks defined in the Phase 0 spec and blocks with indices 2, 3 represent SignedBeaconBlocks defined in the Altair spec.

Note: If fork_block is missing, then all block data should be interpreted as belonging to the post fork.

post.ssz_snappy

A SSZ-snappy encoded BeaconState according to the specification of the post fork, the state after running the block transitions.

Condition

The resulting state should match the expected post state.