Allow incorrect fee extensions on domain creates with default tokens (#1927)

* Modify fee extension to accept larger costs on creates with default tokens

* Add tests

* Add some comments to tests

core/src/main/java/google/registry/flows/domain/DomainCreateFlow.java

@@ -280,8 +280,12 @@ public final class DomainCreateFlow implements TransactionalFlow {
             registrarId,
             now,
             eppInput.getSingleExtension(AllocationTokenExtension.class));
+    boolean defaultTokenUsed = false;
     if (!allocationToken.isPresent() && !registry.getDefaultPromoTokens().isEmpty()) {
       allocationToken = checkForDefaultToken(registry, command);
+      if (allocationToken.isPresent()) {
+        defaultTokenUsed = true;
+      }
     }
     boolean isAnchorTenant =
         isAnchorTenant(
@@ -340,7 +344,7 @@ public final class DomainCreateFlow implements TransactionalFlow {
     FeesAndCredits feesAndCredits =
         pricingLogic.getCreatePrice(
             registry, targetId, now, years, isAnchorTenant, allocationToken);
-    validateFeeChallenge(feeCreate, feesAndCredits);
+    validateFeeChallenge(feeCreate, feesAndCredits, defaultTokenUsed);
     Optional<SecDnsCreateExtension> secDnsCreate =
         validateSecDnsExtension(eppInput.getSingleExtension(SecDnsCreateExtension.class));
     DateTime registrationExpirationTime = leapSafeAddYears(now, years);

core/src/main/java/google/registry/flows/domain/DomainFlowUtils.java

@@ -778,12 +778,13 @@ public class DomainFlowUtils {
    */
   public static void validateFeeChallenge(
       final Optional<? extends FeeTransformCommandExtension> feeCommand,
-      FeesAndCredits feesAndCredits)
+      FeesAndCredits feesAndCredits,
+      boolean defaultTokenUsed)
       throws EppException {
     if (feesAndCredits.hasAnyPremiumFees() && !feeCommand.isPresent()) {
       throw new FeesRequiredForPremiumNameException();
     }
-    validateFeesAckedIfPresent(feeCommand, feesAndCredits);
+    validateFeesAckedIfPresent(feeCommand, feesAndCredits, defaultTokenUsed);
   }
 
   /**
@@ -795,7 +796,8 @@ public class DomainFlowUtils {
    */
   public static void validateFeesAckedIfPresent(
       final Optional<? extends FeeTransformCommandExtension> feeCommand,
-      FeesAndCredits feesAndCredits)
+      FeesAndCredits feesAndCredits,
+      boolean defaultTokenUsed)
       throws EppException {
     // Check for the case where a fee command extension was required but not provided.
     // This only happens when the total fees are non-zero and include custom fees requiring the
@@ -856,7 +858,9 @@ public class DomainFlowUtils {
     // Checking if total amount is expected. Extra fees that we are not expecting may be passed in.
     // Or if there is only a single fee type expected.
     if (!feeTotal.equals(feesAndCredits.getTotalCost())) {
-      throw new FeesMismatchException(feesAndCredits.getTotalCost());
+      if (!defaultTokenUsed || feeTotal.isLessThan(feesAndCredits.getTotalCost())) {
+        throw new FeesMismatchException(feesAndCredits.getTotalCost());
+      }
     }
   }
 

core/src/main/java/google/registry/flows/domain/DomainRenewFlow.java

@@ -199,7 +199,7 @@ public final class DomainRenewFlow implements TransactionalFlow {
             now,
             years,
             existingRecurringBillingEvent);
-    validateFeeChallenge(feeRenew, feesAndCredits);
+    validateFeeChallenge(feeRenew, feesAndCredits, false);
     flowCustomLogic.afterValidation(
         AfterValidationParameters.newBuilder()
             .setExistingDomain(existingDomain)

core/src/main/java/google/registry/flows/domain/DomainRestoreRequestFlow.java

@@ -226,7 +226,7 @@ public final class DomainRestoreRequestFlow implements TransactionalFlow {
     if (!existingDomain.getGracePeriodStatuses().contains(GracePeriodStatus.REDEMPTION)) {
       throw new DomainNotEligibleForRestoreException();
     }
-    validateFeeChallenge(feeUpdate, feesAndCredits);
+    validateFeeChallenge(feeUpdate, feesAndCredits, false);
   }
 
   private static Domain performRestore(

core/src/main/java/google/registry/flows/domain/DomainTransferRequestFlow.java

@@ -210,7 +210,7 @@ public final class DomainTransferRequestFlow implements TransactionalFlow {
     }
 
     if (feesAndCredits.isPresent()) {
-      validateFeeChallenge(feeTransfer, feesAndCredits.get());
+      validateFeeChallenge(feeTransfer, feesAndCredits.get(), false);
     }
     HistoryEntryId domainHistoryId = createHistoryEntryId(existingDomain);
     historyBuilder

core/src/main/java/google/registry/flows/domain/DomainUpdateFlow.java

@@ -231,7 +231,7 @@ public final class DomainUpdateFlow implements TransactionalFlow {
     Optional<FeeUpdateCommandExtension> feeUpdate =
         eppInput.getSingleExtension(FeeUpdateCommandExtension.class);
     FeesAndCredits feesAndCredits = pricingLogic.getUpdatePrice(registry, targetId, now);
-    validateFeesAckedIfPresent(feeUpdate, feesAndCredits);
+    validateFeesAckedIfPresent(feeUpdate, feesAndCredits, false);
     verifyNotInPendingDelete(
         add.getContacts(),
         command.getInnerChange().getRegistrant(),