# Week 9

Hi everyone, this week I got started to writing unit tests for my PR which implements a function to calculate field roots for a block body in any fork.

## Setting up the tests

blockBodyXXX := hydrateBeaconBlockBodyXXX()
i, err := NewBeaconBlockBody(blockBodyXXX)
require.NoError(t, err)

b := i.(*BeaconBlockBody)

This block of code is common to all the forks, we just need to replace the `XXX` with the required fork name.

The first line just sets up a block body of the relevant fork with empty fields but correct sizes. The second line returns an interface which is then then typecasted into a `BeaconBlockBody` for further work.

## Phase 0 test

fieldRoots, err := ComputeBlockBodyFieldRoots(context.Background(), b)
require.NoError(t, err)
trie, err := trie.GenerateTrieFromItems(fieldRoots, 3)
require.NoError(t, err)
layers := trie.ToProto().GetLayers()

hash := layers[len(layers)-1].Layer[0]
require.NoError(t, err)

correctHash, err := b.HashTreeRoot()
require.NoError(t, err)

require.DeepEqual(t, correctHash[:], hash)

The `HashTreeRoot` function is called on the typecasted block body which returns the correct hash. The test hash is computed by the `ComputeBlockBodyFieldRoots` function(the function we are testing mainly) and is then compared with the correct hash to check for the correctness of the former.

## What's Next

Right now I am yet to write the tests upto Electra, which I should be finishing soon unless I get some blockers.