diff --git a/.gas-snapshot b/.gas-snapshot
index a978abc..a9cf629 100644
--- a/.gas-snapshot
+++ b/.gas-snapshot
@@ -1,3 +1,4 @@
+ZenithTest:test_addSequencer() (gas: 88191)
 ZenithTest:test_badSignature() (gas: 37477)
 ZenithTest:test_configureEnter() (gas: 82311)
 ZenithTest:test_disallowedEnter() (gas: 17916)
@@ -7,13 +8,16 @@ ZenithTest:test_enterToken_defaultChain() (gas: 62915)
 ZenithTest:test_enterTransact() (gas: 60890)
 ZenithTest:test_enter_defaultChain() (gas: 24033)
 ZenithTest:test_fallback() (gas: 21534)
-ZenithTest:test_incorrectHostBlock() (gas: 35288)
-ZenithTest:test_notSequencer() (gas: 34201)
-ZenithTest:test_onePerBlock() (gas: 68453)
+ZenithTest:test_incorrectHostBlock() (gas: 35310)
+ZenithTest:test_notSequencer() (gas: 34223)
+ZenithTest:test_notSequencerAdmin() (gas: 10193)
+ZenithTest:test_onePerBlock() (gas: 68463)
 ZenithTest:test_onlyTokenAdmin() (gas: 16926)
 ZenithTest:test_receive() (gas: 21384)
+ZenithTest:test_removeSequencer() (gas: 39857)
 ZenithTest:test_setUp() (gas: 16968)
-ZenithTest:test_submitBlock() (gas: 61187)
+ZenithTest:test_setUp() (gas: 8434)
+ZenithTest:test_submitBlock() (gas: 63468)
 ZenithTest:test_transact() (gas: 58562)
 ZenithTest:test_transact_defaultChain() (gas: 57475)
 ZenithTest:test_withdraw() (gas: 59033)
\ No newline at end of file
diff --git a/test/Zenith.t.sol b/test/Zenith.t.sol
index b7eddeb..9020f84 100644
--- a/test/Zenith.t.sol
+++ b/test/Zenith.t.sol
@@ -23,6 +23,8 @@ contract ZenithTest is Test {
         bytes32 blockDataHash
     );
 
+    event SequencerSet(address indexed sequencer, bool indexed permissioned);
+
     function setUp() public {
         address[] memory initialEnterTokens;
         target = new Zenith(block.chainid + 1, address(this), initialEnterTokens, address(this));
@@ -39,13 +41,18 @@ contract ZenithTest is Test {
         commit = target.blockCommitment(header);
     }
 
+    function test_setUp() public {
+        assertEq(target.sequencerAdmin(), address(this));
+        assertEq(target.deployBlockNumber(), block.number);
+    }
+
     // cannot submit block with incorrect host block number
     function test_incorrectHostBlock() public {
         // change to incorrect host block number
         header.hostBlockNumber = 100;
         commit = target.blockCommitment(header);
 
-        // sign block commitmenet with sequencer key
+        // sign block commitment with sequencer key
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(sequencerKey, commit);
 
         vm.expectRevert(Zenith.IncorrectHostBlock.selector);
@@ -54,20 +61,24 @@ contract ZenithTest is Test {
 
     // can submit block successfully with acceptable header & correct signature provided
     function test_submitBlock() public {
-        // sign block commitmenet with correct sequencer key
+        // sign block commitment with correct sequencer key
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(sequencerKey, commit);
 
+        assertEq(target.lastSubmittedAtBlock(header.rollupChainId), 0);
+
         // should emit BlockSubmitted event
         vm.expectEmit();
         emit BlockSubmitted(
             vm.addr(sequencerKey), header.rollupChainId, header.gasLimit, header.rewardAddress, header.blockDataHash
         );
         target.submitBlock(header, v, r, s, blockData);
+
+        assertEq(target.lastSubmittedAtBlock(header.rollupChainId), block.number);
     }
 
     // cannot submit block with invalid sequencer signer from non-permissioned key
     function test_notSequencer() public {
-        // sign block commitmenet with NOT sequencer key
+        // sign block commitment with NOT sequencer key
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(notSequencerKey, commit);
 
         vm.expectRevert(abi.encodeWithSelector(Zenith.BadSignature.selector, vm.addr(notSequencerKey)));
@@ -76,7 +87,7 @@ contract ZenithTest is Test {
 
     // cannot submit block with sequencer signature over different block header data
     function test_badSignature() public {
-        // sign original block commitmenet with sequencer key
+        // sign original block commitment with sequencer key
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(sequencerKey, commit);
 
         // change header data from what was signed by sequencer
@@ -90,7 +101,7 @@ contract ZenithTest is Test {
 
     // cannot submit two rollup blocks within one host block
     function test_onePerBlock() public {
-        // sign block commitmenet with correct sequencer key
+        // sign block commitment with correct sequencer key
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(sequencerKey, commit);
 
         // should emit BlockSubmitted event
@@ -105,4 +116,48 @@ contract ZenithTest is Test {
         vm.expectRevert(Zenith.OneRollupBlockPerHostBlock.selector);
         target.submitBlock(header, v, r, s, blockData);
     }
+
+    function test_addSequencer() public {
+        address newSequencer = vm.addr(notSequencerKey);
+        assertFalse(target.isSequencer(newSequencer));
+
+        vm.expectEmit();
+        emit SequencerSet(newSequencer, true);
+        target.addSequencer(newSequencer);
+
+        assertTrue(target.isSequencer(newSequencer));
+
+        // can sign block now with new sequencer key
+        (uint8 v, bytes32 r, bytes32 s) = vm.sign(notSequencerKey, commit);
+        vm.expectEmit();
+        emit BlockSubmitted(
+            newSequencer, header.rollupChainId, header.gasLimit, header.rewardAddress, header.blockDataHash
+        );
+        target.submitBlock(header, v, r, s, blockData);
+    }
+
+    function test_removeSequencer() public {
+        address sequencer = vm.addr(sequencerKey);
+        assertTrue(target.isSequencer(sequencer));
+
+        vm.expectEmit();
+        emit SequencerSet(sequencer, false);
+        target.removeSequencer(sequencer);
+
+        assertFalse(target.isSequencer(sequencer));
+
+        // cannot sign block with the sequencer key
+        (uint8 v, bytes32 r, bytes32 s) = vm.sign(sequencerKey, commit);
+        vm.expectRevert(abi.encodeWithSelector(Zenith.BadSignature.selector, vm.addr(sequencerKey)));
+        target.submitBlock(header, v, r, s, blockData);
+    }
+
+    function test_notSequencerAdmin() public {
+        vm.startPrank(address(0x01));
+        vm.expectRevert(Zenith.OnlySequencerAdmin.selector);
+        target.addSequencer(address(0x02));
+
+        vm.expectRevert(Zenith.OnlySequencerAdmin.selector);
+        target.removeSequencer(address(0x02));
+    }
 }