added test for interrupted storage range requests

Signed-off-by: garyschulte <[email protected]>

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/snap/SnapServer.java

@@ -263,7 +263,7 @@ MessageData constructGetStorageRangeResponse(final MessageData message) {
                             statefulPredicate);
                     collectedStorages.add(accountStorages);
 
-                    if (!statefulPredicate.shouldGetMore()) {
+                    if (!statefulPredicate.shouldGetMore() && accountStorages.size() > 0) {
                       // if we were interrupted in the middle of account storage, save last key
                       needsProofStorageSlot =
                           Optional.of(accountStorages.lastKey()).map(Hash::wrap);

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/manager/snap/SnapServerTest.java

@@ -109,7 +109,7 @@ public void assertEmptyRangeLeftProofOfExclusionAndNextAccount() {
   }
 
   @Test
-  public void assertLimitRangeResponse() {
+  public void assertAccountLimitRangeResponse() {
     // assert we limit the range response according to size
     final int acctCount = 2000;
     final long acctRLPSize = 105;
@@ -178,6 +178,7 @@ public void assertCompleteStorageForSingleAccount() {
     assertThat(slotsData.slots().size()).isEqualTo(1);
     var firstAccountStorages = slotsData.slots().first();
     assertThat(firstAccountStorages.size()).isEqualTo(10);
+    // no proofs for complete storage range:
     assertThat(slotsData.proofs().size()).isEqualTo(0);
 
     // TODO: fixme, prob a fixture issue with contract storage.
@@ -186,6 +187,52 @@ public void assertCompleteStorageForSingleAccount() {
     //    .isTrue();
   }
 
+  @Test
+  public void assertStorageLimitRangeResponse() {
+    // assert we limit the range response according to bytessize
+    final int storageSlotSize = 70;
+    final int storageSlotCount = 16;
+    insertTestAccounts(acct1, acct2, acct3, acct4);
+
+    final BytesValueRLPOutput tmp = new BytesValueRLPOutput();
+    tmp.startList();
+    tmp.writeBigIntegerScalar(BigInteger.ONE);
+    tmp.writeBytes(storageTrie.getRootHash());
+    tmp.writeList(
+        List.of(acct3.addressHash, acct4.addressHash),
+        (hash, rlpOutput) -> rlpOutput.writeBytes(hash));
+    tmp.writeBytes(Hash.ZERO);
+    tmp.writeBytes(HASH_LAST);
+    tmp.writeBigIntegerScalar(BigInteger.valueOf(storageSlotCount * storageSlotSize));
+    tmp.endList();
+    var tinyRangeLimit = new GetStorageRangeMessage(tmp.encoded());
+
+    var rangeData =
+        (StorageRangeMessage) snapServer.constructGetStorageRangeResponse(tinyRangeLimit);
+
+    // assert proofs are valid for the requested range
+    assertThat(rangeData).isNotNull();
+    var slotsData = rangeData.slotsData(false);
+    assertThat(slotsData).isNotNull();
+    assertThat(slotsData.slots()).isNotNull();
+    assertThat(slotsData.slots().size()).isEqualTo(2);
+    var firstAccountStorages = slotsData.slots().first();
+    // expecting to see complete 10 slot storage for acct3
+    assertThat(firstAccountStorages.size()).isEqualTo(10);
+    var secondAccountStorages = slotsData.slots().last();
+    // expecting to see only 6 since request was limited to 16 slots
+    assertThat(secondAccountStorages.size()).isEqualTo(6);
+    // proofs required for interrupted storage range:
+    assertThat(slotsData.proofs().size()).isNotEqualTo(0);
+
+    // TODO: fixme, prob a fixture issue with contract storage.
+    // assertThat(
+    //        assertIsValidStorageProof(acct4, Hash.ZERO, secondAccountStorages,
+    // slotsData.proofs()))
+    //    .isTrue();
+
+  }
+
   @Test
   public void assertAccountTriePathRequest() {
     insertTestAccounts(acct1, acct2, acct3, acct4);