Add BeaconBlock genesis

beacon_chain/genesis/src/beacon_block.rs

@@ -0,0 +1,38 @@
+use bls::Signature;
+use spec::ChainSpec;
+use types::{BeaconBlock, BeaconBlockBody};
+
+/// Generate a genesis BeaconBlock.
+pub fn genesis_beacon_block(spec: &ChainSpec) -> BeaconBlock {
+    BeaconBlock {
+        slot: spec.initial_slot_number,
+        parent_root: spec.zero_hash,
+        state_root: spec.zero_hash,
+        randao_reveal: spec.zero_hash,
+        candidate_pow_receipt_root: spec.zero_hash,
+        signature: Signature::default(),
+        body: BeaconBlockBody {
+            proposer_slashings: vec![],
+            casper_slashings: vec![],
+            attestations: vec![],
+            deposits: vec![],
+            exits: vec![],
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // TODO: enhance these tests.
+    // https://github.com/sigp/lighthouse/issues/117
+
+    #[test]
+    fn test_genesis() {
+        let spec = ChainSpec::foundation();
+
+        // This only checks that the function runs without panic.
+        genesis_beacon_block(&spec);
+    }
+}