[L-03] fix of revocation state inconsistency in CertifierHbbft Contract

contracts/CertifierHbbft.sol

@@ -75,7 +75,12 @@ contract CertifierHbbft is Initializable, OwnableUpgradeable, ICertifier {
     /// Can only be called by the `owner`.
     /// @param _who The address for which transactions with a zero gas price must be denied.
     function revoke(address _who) external onlyOwner {
+        if (!_certified[_who]) {
+            return;
+        }
+
         _certified[_who] = false;
+
         emit Revoked(_who);
     }
 

test/CertifierHbbft.ts

@@ -143,7 +143,7 @@ describe('CertifierHbbft contract', () => {
                 .withArgs(caller.address);
         });
 
-        it("should sertify address", async function () {
+        it("should certify address", async function () {
             const { certifier } = await loadFixture(deployContracts);
             const who = accounts[4];
 
@@ -173,6 +173,20 @@ describe('CertifierHbbft contract', () => {
             expect(await certifier.certified(who.address)).to.be.false;
         });
 
+        it("should do nothing if revoking from uncertified address", async function () {
+            const { certifier } = await loadFixture(deployContracts);
+            const who = accounts[9];
+
+            expect(await certifier.certifiedExplicitly(who.address)).to.be.false;
+            expect(await certifier.certified(who.address)).to.be.false;
+
+            await expect(certifier.connect(owner).revoke(who.address))
+                .to.not.emit(certifier, "Revoked");
+
+            expect(await certifier.certifiedExplicitly(who.address)).to.be.false;
+            expect(await certifier.certified(who.address)).to.be.false;
+        });
+
         it("validator account should be certified by default", async function () {
             const { certifier } = await loadFixture(deployContracts);