* rename verifiers
* rename `PreparedBlock` to `SemanticallyVerifiedBlock`
* rename `CommitBlock` to `SemanticallyVerifiedBlock`
* rename `FinalizedBlock` to `CheckpointVerifiedBlock`
* rename `CommitFinalizedBlock` to `CommitCheckpointVerifiedBlock`
* rename `FinalizedWithTrees` to `ContextuallyVerifiedBlockWithTrees`
* rename `ContextuallyValidBlock` to `ContextuallyVerifiedBlock`
* change some `finalized` variables or function arguments to `checkpoint_verified`
* fix docs
* document the difference between `CheckpointVerifiedBlock` and `ContextuallyVerifiedBlock`
* fix doc links
* apply suggestions to request
Co-authored-by: Marek <mail@marek.onl>
* apply suggestions to service
Co-authored-by: Marek <mail@marek.onl>
* apply suggestions to finalized_state.rs and write.rs
Co-authored-by: Marek <mail@marek.onl>
* fmt
* change some more variable names
* change a few missing generics
* fix checkpoint log issue
* rename more `prepared` vars `semantically_verified`
* fix test regex
* fix test regex 2
---------
Co-authored-by: Marek <mail@marek.onl>
* Adds `maturity_height` to VerifiedUnminedTx
Filters out transactions that are invalid at next_block_height in getblocktemplate method
* Adds unit testing
* rustfmt
* rejects txs with immature coinbase spends from mempool
* Condenses fns for transparent coinbase spend check
* Updates calls to VerifiedUnminedTx::new()
* Update zebra-chain/src/transparent/utxo.rs
* Applies suggestions from code review
* Security: Limit the number of non-finalized chains tracked by Zebra
* Use NonFinalizedState::chain_iter() to access private field
* Reverse the order of chain_iter()
* adds ValidateBlock request to state
* adds `Request` enum in block verifier
skips solution check for BlockProposal requests
calls CheckBlockValidity instead of Commit block for BlockProposal requests
* uses new Request in references to chain verifier
* adds getblocktemplate proposal mode response type
* makes getblocktemplate-rpcs feature in zebra-consensus select getblocktemplate-rpcs in zebra-state
* Adds PR review revisions
* adds info log in CheckBlockProposalValidity
* Reverts replacement of match statement
* adds `GetBlockTemplate::capabilities` fn
* conditions calling checkpoint verifier on !request.is_proposal
* updates references to validate_and_commit_non_finalized
* adds snapshot test, updates test vectors
* adds `should_count_metrics` to NonFinalizedState
* Returns an error from chain verifier for block proposal requests below checkpoint height
adds feature flags
* adds "proposal" to GET_BLOCK_TEMPLATE_CAPABILITIES_FIELD
* adds back block::Request to zebra-consensus lib
* updates snapshots
* Removes unnecessary network arg
* skips req in tracing intstrument for read state
* Moves out block proposal validation to its own fn
* corrects `difficulty_threshold_is_valid` docs
adds/fixes some comments, adds TODOs
general cleanup from a self-review.
* Update zebra-state/src/service.rs
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* Update zebra-rpc/src/methods/get_block_template_rpcs.rs
Co-authored-by: teor <teor@riseup.net>
* check best chain tip
* Update zebra-state/src/service.rs
Co-authored-by: teor <teor@riseup.net>
* Applies cleanup suggestions from code review
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* updates comments
* adds check nullifier no dup fns for transactions
* Adds:
- check::anchors fn for tx iter
- TODO comments for unifying nullifiers and anchors checks
- new state request
Updates unknown anchor errors to accomodate tx-only check
Calls new state fn from transaction verifier
* updates check::anchors fns to use transactions
updates TransactionContextualValidity request to check sprout anchors
adds comment mentioning TransactionContextualValidity ignores UTXOs
* conditions new state req call on is_mempool
updates tests
* fix doc link / lint error
* checks for duplicate nullifiers with closures
* Update zebra-state/src/service/check/nullifier.rs
Co-authored-by: teor <teor@riseup.net>
* documents find_duplicate_nullifier params
moves if let statement into for loop
* renames new state req/res
* asserts correct response variant in tx verifier
* adds CheckBestChainTipShieldedSpends call in tx verifier to async checks
* re-adds tracing instrumentation to check::anchors fn
renames transaction_in_state to transaction_in_chain
* adds block/tx wrapper fns for anchors checks
* uses UnminedTx instead of transaction.hash()
deletes broken test
* updates new state req/res name
* updates tests and uses par_iter for anchors checks
* Updates check::anchors pub fn docs.
* Adds:
- comments / docs
- a TransactionError variant for ValidateContextError
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* moves downcast to From impl
rustfmt
* moves the ValidateContextError into an Arc
updates comments and naming
* leaves par_iter for another PR
* puts io::Error in an Arc
* updates anchors tests to call tx_anchors check
* updates tests to call tx_no_duplicates_in_chain
slightly improves formatting
* Update zebra-consensus/src/error.rs
Co-authored-by: teor <teor@riseup.net>
* moves Arc from HistoryError to ValidateContextError
Co-authored-by: teor <teor@riseup.net>
* Add a new block commit task and channels, that don't do anything yet
* Add last_block_hash_sent to the state service, to avoid database accesses
* Update last_block_hash_sent regardless of commit errors
* Rename a field to StateService.max_queued_finalized_height
* Commit finalized blocks to the state in a separate task
* Check for panics in the block write task
* Wait for the block commit task in tests, and check for errors
* Always run a proptest that sleeps once
* Add extra debugging to state shutdowns
* Work around a RocksDB shutdown bug
* Close the finalized block channel when we're finished with it
* Only reset state queue once per error
* Update some TODOs
* Add a module doc comment
* Drop channels and check for closed channels in the block commit task
* Close state channels and tasks on drop
* Remove some duplicate fields across StateService and ReadStateService
* Try tweaking the shutdown steps
* Update and clarify some comments
* Clarify another comment
* Don't try to cancel RocksDB background work on drop
* Fix up some comments
* Remove some duplicate code
* Remove redundant workarounds for shutdown issues
* Remode a redundant channel close in the block commit task
* Remove a mistaken `!force` shutdown condition
* Remove duplicate force-shutdown code and explain it better
* Improve RPC error logging
* Wait for chain tip updates in the RPC tests
* Wait 2 seconds for chain tip updates before skipping them
* Remove an unnecessary block_in_place()
* Fix some test error messages that were changed by earlier fixes
* Expand some comments, fix typos
Co-authored-by: Marek <mail@marek.onl>
* Actually drop children of failed blocks
* Explain why we drop descendants of failed blocks
* Clarify a comment
* Wait for chain tip updates in a failing test on macOS
* Clean duplicate finalized blocks when the non-finalized state activates
* Send an error when receiving a duplicate finalized block
* Update checkpoint block behaviour, document its consensus rule
* Wait for chain tip changes in inbound_block_height_lookahead_limit test
* Wait for the genesis block to commit in the fake peer set mempool tests
* Disable unreliable mempool verification check in the send transaction test
* Appease rustfmt
* Use clear_finalized_block_queue() everywhere that blocks are dropped
* Document how Finalized and NonFinalized clones are different
* sends non-finalized blocks to the block write task
* passes ZebraDb to commit_new_chain, commit_block, and no_duplicates_in_finalized_chain instead of FinalizedState
* Update zebra-state/src/service/write.rs
Co-authored-by: teor <teor@riseup.net>
* updates comments, renames send_process_queued, other minor cleanup
* update assert_block_can_be_validated comment
* removes `mem` field from StateService
* removes `disk` field from StateService and updates block_iter to use `ZebraDb` instead of the finalized state
* updates tests that use the disk to use read_service.db instead
* moves best_tip to a read fn and returns finalized & non-finalized states from setup instead of the state service
* changes `contextual_validity` to get the network from the finalized_state instead of another param
* swaps out StateService with FinalizedState and NonFinalizedState in tests
* adds NotReadyToBeCommitted error and returns it from validate_and_commit when a blocks parent hash is not in any chain
* removes NonFinalizedWriteCmd and calls, moves update_latest_channels above rsp_tx.send
* makes parent_errors_map an indexmap
* clears non-finalized block queue when the receiver is dropped and when the StateService is being dropped
* sends non-finalized blocks to the block write task
* passes ZebraDb to commit_new_chain, commit_block, and no_duplicates_in_finalized_chain instead of FinalizedState
* updates comments, renames send_process_queued, other minor cleanup
* Update zebra-state/src/service/write.rs
Co-authored-by: teor <teor@riseup.net>
* update assert_block_can_be_validated comment
* removes `mem` field from StateService
* removes `disk` field from StateService and updates block_iter to use `ZebraDb` instead of the finalized state
* updates tests that use the disk to use read_service.db instead
* moves best_tip to a read fn and returns finalized & non-finalized states from setup instead of the state service
* changes `contextual_validity` to get the network from the finalized_state instead of another param
* swaps out StateService with FinalizedState and NonFinalizedState in tests
* adds NotReadyToBeCommitted error and returns it from validate_and_commit when a blocks parent hash is not in any chain
* removes NonFinalizedWriteCmd and calls, moves update_latest_channels above rsp_tx.send
* makes parent_errors_map an indexmap
* clears non-finalized block queue when the receiver is dropped and when the StateService is being dropped
* removes duplicate field definitions on StateService that were a result of a bad merge
* update NotReadyToBeCommitted error message
* Appear rustfmt
* Fix doc links
* Rename a function to initial_contextual_validity()
* Do error tasks on Err, and success tasks on Ok
* Simplify parent_error_map truncation
* Rewrite best_tip() to use tip()
* Rename latest_mem() to latest_non_finalized_state()
```sh
fastmod latest_mem latest_non_finalized_state zebra*
cargo fmt --all
```
* Simplify latest_non_finalized_state() using a new WatchReceiver API
* Expand some error messages
* Send the result after updating the channels, and document why
* wait for chain_tip_update before cancelling download in mempool_cancel_mined
* adds `sent_non_finalized_block_hashes` field to StateService
* adds batched sent_hash insertions and checks sent hashes in queue_and_commit_non_finalized before adding a block to the queue
* check that the `curr_buf` in SentHashes is not empty before pushing it to the `sent_bufs`
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* Fix rustfmt
* Check for finalized block heights using zs_contains()
* adds known_utxos field to SentHashes
* updates comment on SentHashes.add method
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* return early when there's a duplicate hash in QueuedBlocks.queue instead of panicking
* Make finalized UTXOs near the final checkpoint available for full block verification
* Replace a checkpoint height literal with the actual config
* Update mainnet and testnet checkpoints - 7 October 2022
* Fix some state service init arguments
* Allow more lookahead in the downloader, but less lookahead in the syncer
* Add the latest config to the tests, and fix the latest config check
* Increase the number of finalized blocks checked for non-finalized block UTXO spends
* fix(log): reduce verbose logs for block commits (#5348)
* Remove some verbose block write channel logs
* Only warn about tracing endpoint if the address is actually set
* Use CloneError instead of formatting a non-cloneable error
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Increase block verify timeout
* Work around a known block timeout bug by using a shorter timeout
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: Marek <mail@marek.onl>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Add history trees for each height in non-fin state
* Refactor formatting
* Pass the treestate to the finalized state
I created a new structure `FinalizedBlockWithTrees` that wraps the
treestate and the finalized block. I did that because the original
`FinalizedBlock` is `Eq`, but `HistoryTree` can't be `Eq`.
This makes Zebra faster because:
1. The finalized state doesn't retrieve the treestate from the disk if
the non-finalized state supplies it.
2.The finalized state doesn't recompute the treestate if the
non-finalized state supplies it.
* Check block commitment before updating hist tree
* Store Sprout commitment trees in non-fin state
* Send trees for the root block to fin-state
When committing a block and sending the treestate from the non-finalized
state to the finalized state, Zebra was sending trees that correspond to
the tip block instead of trees that correspond to the root block of the
best chain. This commit fixes that.
* Refactor doc comments
* Refactor block finalization
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Derive Hash for transparent address index types
* Expose some types used by transparent address indexes
* Add an empty transparent transfers type for transparent address indexes
* Update TransparentTransfers with created UTXOs
* Add spent transparent outputs to ContextuallyValidBlock
* Update TransparentTransfers with spent transparent outputs
* Ignore missing spent outputs, so that tests pass
* Remove empty TransparentTransfers after a spend revert
* Update TransparentTransfers with creating and spending transaction IDs
* Ignore duplicate created UTXOs, so that tests pass
* Add some TODO comments
* Remove accidental doctest formatting
* Add address transfers index accessor methods
* Use TransactionLocation in the non-finalized state
* Apply more address index assertions to production code
* Refactor deeply nested code and apply more assertions
* Return UTXOs in chain order
* Return transaction hashes in chain order
* Stop indexing each transparent output multiple times
* Run some more asserts during tests
* Tidy TODO comments
* Fix an incorrect assert condition
* Use OrderedUtxos so that spent UTXOs can be stored in chain order
* Update tests to use OrderedUtxos
* Update the index API for the getaddressutxos query
* Remove redundant arguments in tests
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Support large block heights
* Document consensus rules referring to expiry heights
* Refactor the docs
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* Fix the formatting of an error message
* refactor: Simplify coinbase expiry code so the consensus rule is clear (#3408)
* Fix some outdated TODO comments
* refactor(coinbase expiry): Simplify the code so consensus rule is clear
* Fix the formatting of an error message
* Remove a redundant comment
Co-authored-by: Marek <mail@marek.onl>
Co-authored-by: Marek <mail@marek.onl>
* Check the max expiry height at parse time
* Test that 2^31 - 1 is the last valid height
* Add tests for nExpiryHeight
* Add tests for expiry heights of V4 transactions
* Add tests for V5 transactions
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Do prelim checking of Sprout anchors in non-finalized state
Does not check intra-transaction interstitial states yet
* Populate sprout anchors to allow other state tests to pass
* Preliminary interstitial sprout note commitment tree anchor checks implementation
* Make sure only prior anchors are checked in the same transaction
* Add tests
* Refactor a comment
* Refactor rustdoc
Co-authored-by: Deirdre Connolly <deirdre@zfnd.org>
* Use the first `JoinSplit`s from mainnet
* Print debug messages
* Use correct blocks for the tests
Co-authored-by: Marek <mail@marek.onl>
Co-authored-by: Conrado Gouvea <conrado@zfnd.org>
* Add Transaction::sprout_joinsplits()
* Add Anchor variants to ValidateContextError
* Make Chain anchor collections pub(crate)
* tracing::instrument several methods in state
* Add contains_*_anchors methods to FinalizedState
* Add check::anchors module and function
* Verify that anchors_refer_to_earlier_treestates in when updating chains in non-finalized state
* Update zebra-state/src/service/check/anchors.rs
Co-authored-by: teor <teor@riseup.net>
* Add anchors() to sapling::ShieldedData
* Add sapling_anchors() to Transaction
* Use Transaction::sapling_anchors() in the anchors_refer_to_earlier_treestates() check
* Whoops, itertools
* Add a comment for improvement
Co-authored-by: teor <teor@riseup.net>
* Add & use a cfg(test) method on FinalizedState to prep test state with anchors to allow other tests to pass contextual checks
* Allow test nullifier checks to pass by populating anchor sets, allowing test anchor checks to pass
* Add mainnet block 419202 and its sapling note commitment tree root to test vectors
* Test sapling anchor verification using the first few Sapling blocks data
* Correct comment
* assert_eq instead of assert(bool)
Co-authored-by: Conrado Gouvea <conrado@zfnd.org>
* Update zebra-state/src/service/non_finalized_state.rs
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: Marek <mail@marek.onl>
Co-authored-by: Conrado Gouvea <conrado@zfnd.org>
* Make Amount arithmetic more generic
To modify generated amounts, we need some extra operations on `Amount`.
We also need to extend existing operations to both `NonNegative` and
`NegativeAllowed` amounts.
* Add a constrain method for ValueBalance
* Derive Eq for ValueBalance
* impl Neg for ValueBalance
* Make some Amount arithmetic expectations explicit
* Explain why we use i128 for multiplication
And expand the overflow error details.
* Expand Amount::sum error details
* Make amount::Error field order consistent
* Rename an amount::Error variant to Constraint, so it's clearer
* Add specific pool variants to ValueBalanceError
* Update coinbase remaining value consensus rule comment
This consensus rule was updated recently to include coinbase transactions,
but Zebra doesn't check block subsidy or miner fees yet.
* Add test methods for modifying transparent values and shielded value balances
* Temporarily set values and value balances to zero in proptests
In both generated chains and proptests that construct their own transactions.
Using zero values reduces value calculation and value check test coverage.
A future change will use non-zero values, and fix them so the check passes.
* Add extra fields to remaining transaction value errors
* Swap the transparent value balance sign to match shielded value balances
This makes the signs of all the chain value pools consistent.
* Use a NonNegative constraint for transparent values
This fix:
* makes the type signature match the consensus rules
* avoids having to write code to handle negative values
* Allocate total generated transaction input value to outputs
If there isn't enough input value for an output, set it to zero.
Temporarily reduce all generated values to avoid overflow.
(We'll remove this workaround when we calculate chain value balances.)
* Consistently use ValueBalanceError for ValueBalances
* Make the value balance signs match the spec
And rename and document methods so their signs are clearer.
* Convert amount::Errors to specific pool ValueBalanceErrors
* Move some error changes to the next PR
* Add extra info to remaining transaction value errors (#2585)
* Distinguish between overflow and negative remaining transaction value errors
And make some error types cloneable.
* Add methods for updating chain value pools (#2586)
* Move amount::test to amount::tests:vectors
* Make ValueBalance traits more consistent with Amount
- implement Add and Sub variants with Result and Assign
- derive Hash
* Clarify some comments and expects
* Create ValueBalance update methods for blocks and transactions
Co-authored-by: Alfredo Garcia <oxarbitrage@gmail.com>
* Validate transparent coinbase output maturity and shielding
- Add a CoinbaseSpendRestriction enum and Transaction method
- Validate transparent coinbase spends in non-finalized chains
* Don't use genesis created UTXOs for spends in generated block chains
* Refactor out a new_transaction_ordered_outputs function
* Add Transaction::outputs_mut for tests
* Generate valid transparent spends in arbitrary block chains
* When generating blocks, fixup the block contents, then the block hash
* Test that generated chains contain at least one transparent spend
* Make generated chains long enough for reliable tests
* Add transparent and shielded input and output methods to Transaction
* Split chain generation into 3 functions
* Test that unshielded and immature transparent coinbase spends fail
* Comment punctuation
* Clarify a comment
* Clarify probability calculation
* Test that shielded mature coinbase output spends succeed
* Add `proptest-impl` feature to `zebra-state`
This prepares the `zebra-state` crate to be able to export some
test-specific helper types and functions.
* Add `arbitrary` module to `zebra-state` root
A separate module to contain the `Prepare` trait, since it's required by
some prop-test strategies and therefore can't be in the `tests` module.
* Replace usages of `tests::Prepare`
Use the same trait but placed in a new module that's accessible based on
the feature flag.
* Remove old `Prepare` trait
It was obsoleted by the new copy in the `arbitrary` module.
* Make `StateService` crate-accessible
Prepare for it to be accessible in some test modules.
* Refactor strategy function import
Import the function directly, instead of just its containing module.
* Move some strategy functions to `tests::setup`
Create a new module for the strategy functions that are only used
internally.
Co-authored-by: teor <teor@riseup.net>
* Make some NonFinalizedState methods test-only
* Rename nullifier tests for clarity
* Reduce test times by reducing default proptest cases
The state tests should be about 4x faster after these changes.
They reduce total state test "user CPU" time to 20-30 seconds on my
machine. Previously it was around 2 minutes.
* Replace multiple pushes with extend
Co-authored-by: Alfredo Garcia <oxarbitrage@gmail.com>
* Reject transparent output double-spends
Check that transparent spends use unspent outputs from:
* earlier transaction in the same block,
* earlier blocks in the parent non-finalized chain, or
* the finalized state.
* Fixup UTXOs in proptests
* Add a comment
* Clarify a consensus rule implementation
* Fix an incorrect comment
* Fix an incorrect error message
* Clarify a comment
* Document `unspent_utxos`
* Simplify the UTXO check
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Further simplify and fix the UTXO check
- split each error case into a separate check
- combine `contains` and `insert`
- add a missing check against the non-finalized unspent UTXOs
- rename arguments and edit error strings for clarity
* Share test methods between check test modules
* Make some chain fields available to tests
* Make error field names consistent with transparent::Input
* WIP: Add tests for UTXO double-spends
- accept output and spend in the same block
- accept output and spend in a later block
- reject output and double-spend all in the same block
- reject output then double-spend in a later block
- reject output, spend, then double-spend all in different blocks
* Use Extend rather than multiple pushes
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Use Extend for more pushes
* Limit the number of proptest cases, to speed up tests
* Test rejection of UTXOs that were never in the chain
* Test rejection of spends of later transactions in the same block
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Add sapling and orchard duplicate nullifier errors
* Reject duplicate finalized sapling and orchard nullifiers
Reject duplicate sapling and orchard nullifiers in a new block,
when the block is added to a non-finalized chain,
and the duplicate nullifier is already in the finalized state.
* Reject duplicate non-finalized sapling and orchard nullifiers
Reject duplicate sapling and orchard nullifiers in a new block,
when the block is added to a non-finalized chain,
and the duplicate nullifier is in:
* the same shielded data,
* the same transaction,
* the same block, or
* an earlier block in the non-finalized chain.
* Refactor sprout nullifier tests to remove common code
* Add sapling nullifier tests
Test that the state rejects duplicate sapling nullifiers in a new block,
when the block is added to a non-finalized chain,
and the duplicate nullifier is in:
* the same shielded data,
* the same transaction,
* the same block,
* an earlier block in the non-finalized chain, or
* the finalized state.
* Add orchard nullifier tests
Test that the state rejects duplicate orchard nullifiers in a new block,
when the block is added to a non-finalized chain,
and the duplicate nullifier is in:
* the same shielded data,
* the same transaction,
* the same block,
* an earlier block in the non-finalized chain, or
* the finalized state.
* Check for specific nullifiers in the state in tests
* Replace slices with vectors in arguments
* Remove redundant code and variables
* Simplify sapling TransferData tests
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Remove an extra :
* Remove redundant vec!
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Document Ord for Chain and Proof of Work
* Create a NonFinalizedState::new method
And add some debug and clone derives.
* Test that block rejection restores internal non-finalized chain states
As part of this change, add `eq_internal_state` methods,
and proptests for them.
* Check that the chain's nullifiers are not modified on error
* Clarify a test description
* Refactor loop for readability
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Fix a variable name typo
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* Reject duplicate sprout nullifiers in the state
* Improve docs and error messages
* Clarify "must be present" assert logs
* Move nullifier checks to their own module
Also:
* make non-finalized nullifier checks and errors generic over
sprout, sapling, and orchard
* create and update module and function documentation
* Fix a block type name in docs
* Move state assertions or skip them during tests
These changes enable state testing, while still asserting in production.
* Add sprout duplicate nullifier tests
* Improve comments
* Set value balance to 0 to pass future chain value pool checks
* Test finalized state in sprout nullifier accept test
* Replace assert with expect
* Improve assertion messages
Alfredo Garcia
teor
Arya
Marek
Conrado Gouvea
Deirdre Connolly
Janito Vaqueiro Ferreira Filho