Fix some minor group-related bugs

Incorrect column names when saving a group ban.

Missing column in LeaveGroupTransactions.

More stringent validity checks in group-kick, group-ban and remove-group-admin.

Added loads more tests to cover group actions.

src/main/java/org/qortal/repository/hsqldb/HSQLDBDatabaseUpdates.java

@@ -530,7 +530,7 @@ public class HSQLDBDatabaseUpdates {
 
 					// Leave group
 					stmt.execute("CREATE TABLE LeaveGroupTransactions (signature Signature, leaver QortalPublicKey NOT NULL, group_id GroupID NOT NULL, "
-							+ "member_reference Signature, admin_reference Signature, " + TRANSACTION_KEYS + ")");
+							+ "member_reference Signature, admin_reference Signature, previous_group_id GroupID, " + TRANSACTION_KEYS + ")");
 
 					// Kick from group
 					stmt.execute("CREATE TABLE GroupKickTransactions (signature Signature, admin QortalPublicKey NOT NULL, "
@@ -618,6 +618,11 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("CREATE TABLE PublicizeTransactions (signature Signature, nonce INT NOT NULL, " + TRANSACTION_KEYS + ")");
 					break;
 
+				case 20:
+					// XXX Bug-fix, but remove when we build new genesis
+					stmt.execute("ALTER TABLE LeaveGroupTransactions ADD COLUMN IF NOT EXISTS previous_group_id GroupID");
+					break;
+
 				default:
 					// nothing to do
 					return false;

src/main/java/org/qortal/repository/hsqldb/HSQLDBGroupRepository.java

@@ -828,7 +828,7 @@ public class HSQLDBGroupRepository implements GroupRepository {
 		HSQLDBSaver saveHelper = new HSQLDBSaver("GroupBans");
 
 		saveHelper.bind("group_id", groupBanData.getGroupId()).bind("offender", groupBanData.getOffender()).bind("admin", groupBanData.getAdmin())
-				.bind("banned", groupBanData.getBanned()).bind("reason", groupBanData.getReason()).bind("expiry", groupBanData.getExpiry())
+				.bind("banned_when", groupBanData.getBanned()).bind("reason", groupBanData.getReason()).bind("expires_when", groupBanData.getExpiry())
 				.bind("reference", groupBanData.getReference());
 
 		try {

src/main/java/org/qortal/transaction/GroupBanTransaction.java

@@ -72,7 +72,11 @@ public class GroupBanTransaction extends Transaction {
 
 		Account offender = getOffender();
 
-		// Can't ban another admin unless the group owner
+		// Can't ban group owner
+		if (offender.getAddress().equals(groupData.getOwner()))
+			return ValidationResult.INVALID_GROUP_OWNER;
+
+		// Can't ban another admin unless admin is the group owner
 		if (!admin.getAddress().equals(groupData.getOwner()) && this.repository.getGroupRepository().adminExists(groupId, offender.getAddress()))
 			return ValidationResult.INVALID_GROUP_OWNER;
 

src/main/java/org/qortal/transaction/GroupKickTransaction.java

@@ -74,7 +74,11 @@ public class GroupKickTransaction extends Transaction {
 		if (!groupRepository.joinRequestExists(groupId, member.getAddress()) && !groupRepository.memberExists(groupId, member.getAddress()))
 			return ValidationResult.NOT_GROUP_MEMBER;
 
-		// Can't kick another admin unless the group owner
+		// Can't kick group owner
+		if (member.getAddress().equals(groupData.getOwner()))
+			return ValidationResult.INVALID_GROUP_OWNER;
+
+		// Can't kick another admin unless kicker is the group owner
 		if (!admin.getAddress().equals(groupData.getOwner()) && groupRepository.adminExists(groupId, member.getAddress()))
 			return ValidationResult.INVALID_GROUP_OWNER;
 

src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java

@@ -76,6 +76,10 @@ public class RemoveGroupAdminTransaction extends Transaction {
 		if (!this.repository.getGroupRepository().adminExists(groupId, admin.getAddress()))
 			return ValidationResult.NOT_GROUP_ADMIN;
 
+		// Check admin is not group owner
+		if (admin.getAddress().equals(groupData.getOwner()))
+			return ValidationResult.INVALID_GROUP_OWNER;
+
 		// Check creator has enough funds
 		if (owner.getConfirmedBalance(Asset.QORT) < this.removeGroupAdminTransactionData.getFee())
 			return ValidationResult.NO_BALANCE;