diff --git a/cryptarchia/sync/full_sync.py b/cryptarchia/sync/full_sync.py
index afb25c3..5ba7363 100644
--- a/cryptarchia/sync/full_sync.py
+++ b/cryptarchia/sync/full_sync.py
@@ -7,7 +7,7 @@ SLOT_TOLERANCE = 1
 
 
 def full_sync(local: Follower, remotes: list[Follower], start_slot: Slot):
-    while groups := group_sync_targets(remotes, start_slot):
+    while groups := group_targets(remotes, start_slot):
         for _, group in groups.items():
             remote = group[0]
             range_sync(local, remote, start_slot, remote.tip().slot)
@@ -19,7 +19,7 @@ def range_sync(local: Follower, remote: Follower, from_slot: Slot, to_slot: Slot
         local.on_block(block)
 
 
-def group_sync_targets(
+def group_targets(
     targets: list[Follower], start_slot: Slot
 ) -> dict[Id, list[Follower]]:
     groups: dict[Id, list[Follower]] = defaultdict(list)
diff --git a/cryptarchia/sync/test_full_sync.py b/cryptarchia/sync/test_full_sync.py
index f796d45..2538d7e 100644
--- a/cryptarchia/sync/test_full_sync.py
+++ b/cryptarchia/sync/test_full_sync.py
@@ -1,3 +1,4 @@
+from copy import deepcopy
 from unittest import TestCase
 
 from cryptarchia.cryptarchia import Coin, Follower
@@ -5,8 +6,8 @@ from cryptarchia.sync.full_sync import full_sync
 from cryptarchia.test_common import mk_block, mk_config, mk_genesis_state
 
 
-class TestRangeSync(TestCase):
-    def test_no_fork(self):
+class TestFullSync(TestCase):
+    def test_sync_single_chain(self):
         # b0 - b1 - b2
         coin = Coin(sk=0, value=10)
         config = mk_config([coin])
@@ -22,5 +23,173 @@ class TestRangeSync(TestCase):
 
         new_follower = Follower(genesis, config)
         full_sync(new_follower, [follower], genesis.block.slot)
-        assert new_follower.tip() == b2
-        assert new_follower.forks == []
+        assert new_follower.tip() == follower.tip()
+        assert new_follower.forks == follower.forks
+
+    def test_continue_syncing_single_chain(self):
+        # b0 - b1 - b2
+        coin = Coin(sk=0, value=10)
+        config = mk_config([coin])
+        genesis = mk_genesis_state([coin])
+        follower = Follower(genesis, config)
+        b0, coin = mk_block(genesis.block, 1, coin), coin.evolve()
+        b1, coin = mk_block(b0, 2, coin), coin.evolve()
+        b2, coin = mk_block(b1, 3, coin), coin.evolve()
+        for b in [b0, b1, b2]:
+            follower.on_block(b)
+        assert follower.tip() == b2
+        assert follower.forks == []
+
+        new_follower = deepcopy(follower)
+
+        # follower grows
+        # b0 - b1 - b2 - b3 - b4
+        b3, coin = mk_block(b2, 4, coin), coin.evolve()
+        b4, coin = mk_block(b3, 5, coin), coin.evolve()
+        for b in [b3, b4]:
+            follower.on_block(b)
+        assert follower.tip() == b4
+
+        # new_follower starts syncing from its tip slot
+        full_sync(new_follower, [follower], new_follower.tip().slot)
+        assert new_follower.tip() == follower.tip()
+        assert new_follower.forks == follower.forks
+
+    def test_sync_forks(self):
+        # b0 - b1 - b2 == tip
+        #    \
+        #      b3 - b4
+        c_a, c_b = Coin(sk=0, value=10), Coin(sk=1, value=10)
+        config = mk_config([c_a, c_b])
+        genesis = mk_genesis_state([c_a, c_b])
+        follower = Follower(genesis, config)
+        b0, c_a = mk_block(genesis.block, 1, c_a), c_a.evolve()
+        b1, c_a = mk_block(b0, 2, c_a), c_a.evolve()
+        b2, c_a = mk_block(b1, 3, c_a), c_a.evolve()
+        b3, c_b = mk_block(b0, 2, c_b), c_b.evolve()
+        b4, c_b = mk_block(b3, 3, c_b), c_b.evolve()
+        for b in [b0, b1, b2, b3, b4]:
+            follower.on_block(b)
+        assert follower.tip() == b2
+        assert follower.forks == [b4.id()]
+
+        new_follower = Follower(genesis, config)
+        full_sync(new_follower, [follower], genesis.block.slot)
+        assert new_follower.tip() == follower.tip()
+        assert new_follower.forks == follower.forks
+
+    def test_continue_syncing_forks(self):
+        # b0 - b1 - b2 == tip
+        #    \
+        #      b3 - b4
+        c_a, c_b = Coin(sk=0, value=10), Coin(sk=1, value=10)
+        config = mk_config([c_a, c_b])
+        genesis = mk_genesis_state([c_a, c_b])
+        follower = Follower(genesis, config)
+        b0, c_a = mk_block(genesis.block, 1, c_a), c_a.evolve()
+        b1, c_a = mk_block(b0, 2, c_a), c_a.evolve()
+        b2, c_a = mk_block(b1, 3, c_a), c_a.evolve()
+        b3, c_b = mk_block(b0, 2, c_b), c_b.evolve()
+        b4, c_b = mk_block(b3, 3, c_b), c_b.evolve()
+        for b in [b0, b1, b2, b3, b4]:
+            follower.on_block(b)
+        assert follower.tip() == b2
+        assert follower.forks == [b4.id()]
+
+        new_follower = deepcopy(follower)
+
+        # all forks grow. the tip is switched.
+        # b0 - b1 - b2 - b5
+        #    \
+        #      b3 - b4 - b6 - b7 == tip
+        b5, c_a = mk_block(b2, 4, c_a), c_a.evolve()
+        b6, c_b = mk_block(b4, 4, c_b), c_b.evolve()
+        b7, c_b = mk_block(b6, 5, c_b), c_b.evolve()
+        for b in [b5, b6, b7]:
+            follower.on_block(b)
+        assert follower.tip() == b7
+        assert follower.forks == [b5.id()]
+
+        # new_follower starts syncing from its tip slot
+        full_sync(new_follower, [follower], new_follower.tip().slot)
+        assert new_follower.tip() == follower.tip()
+        assert new_follower.forks == follower.forks
+
+    def test_sync_two_different_trees(self):
+        c_a, c_b = Coin(sk=0, value=10), Coin(sk=1, value=10)
+        config = mk_config([c_a, c_b])
+        genesis = mk_genesis_state([c_a, c_b])
+
+        # Peer 0
+        # b0 - b1 - b2
+        peer_0 = Follower(genesis, config)
+        b0, c_a = mk_block(genesis.block, 1, c_a), c_a.evolve()
+        b1, c_a = mk_block(b0, 2, c_a), c_a.evolve()
+        b2, c_a = mk_block(b1, 3, c_a), c_a.evolve()
+        for b in [b0, b1, b2]:
+            peer_0.on_block(b)
+        assert peer_0.tip() == b2
+        assert peer_0.forks == []
+
+        # Peer 1
+        # b0 - b3 - b4 - b5
+        peer_1 = Follower(genesis, config)
+        b0, c_b = mk_block(genesis.block, 1, c_b), c_b.evolve()
+        b3, c_b = mk_block(b0, 2, c_b), c_b.evolve()
+        b4, c_b = mk_block(b3, 3, c_b), c_b.evolve()
+        b5, c_b = mk_block(b4, 3, c_b), c_b.evolve()
+        for b in [b0, b3, b4, b5]:
+            peer_1.on_block(b)
+        assert peer_1.tip() == b5
+        assert peer_1.forks == []
+
+        # new_follower should have:
+        # b0 - b1 - b2
+        #    \
+        #      b3 - b4 - b5 == tip
+        new_follower = Follower(genesis, config)
+        full_sync(new_follower, [peer_0, peer_1], genesis.block.slot)
+        assert new_follower.tip() == peer_1.tip()
+        assert new_follower.forks == [peer_0.tip_id()]
+
+    def test_ignore_blocks_missing_parents(self):
+        c_a, c_b = Coin(sk=0, value=10), Coin(sk=1, value=10)
+        config = mk_config([c_a, c_b])
+        genesis = mk_genesis_state([c_a, c_b])
+
+        # Peer 0
+        # b0 - b1 - b2
+        peer_0 = Follower(genesis, config)
+        b0, c_a = mk_block(genesis.block, 1, c_a), c_a.evolve()
+        b1, c_a = mk_block(b0, 2, c_a), c_a.evolve()
+        b2, c_a = mk_block(b1, 3, c_a), c_a.evolve()
+        for b in [b0, b1, b2]:
+            peer_0.on_block(b)
+        assert peer_0.tip() == b2
+        assert peer_0.forks == []
+
+        # Peer 1
+        # b0 - b3 - b4 - b5
+        peer_1 = Follower(genesis, config)
+        b0, c_b = mk_block(genesis.block, 1, c_b), c_b.evolve()
+        b3, c_b = mk_block(b0, 2, c_b), c_b.evolve()
+        b4, c_b = mk_block(b3, 3, c_b), c_b.evolve()
+        b5, c_b = mk_block(b4, 3, c_b), c_b.evolve()
+        for b in [b0, b3, b4, b5]:
+            peer_1.on_block(b)
+        assert peer_1.tip() == b5
+        assert peer_1.forks == []
+
+        # new follower syncs the peer 0 first
+        new_follower = Follower(genesis, config)
+        full_sync(new_follower, [peer_0], genesis.block.slot)
+        assert new_follower.tip() == peer_0.tip()
+        assert new_follower.forks == peer_0.forks
+
+        # new follower tries to sync the peer 1, but from its tip slot (3).
+        # causing all blocks from the peer 1 to be ignored
+        # because the peer 1 has a fork different from the peer 0,
+        # and the new follower hasn't synced the peer 1 fork until the slot 3.
+        full_sync(new_follower, [peer_1], new_follower.tip().slot)
+        assert new_follower.tip() == peer_0.tip()
+        assert new_follower.forks == peer_0.forks