paddle

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Paddle for Waves

Paddle is a Java library to write tests for your dApps and other smart contracts on Waves blockchain.

Эта документация доступна на русском языке.

Table of Contents

Getting started

Requirements

Installation

The easiest way to get started is to create a new project from the paddle-example GitHub template.

Or add Paddle as dependency to your existing project.

Maven

<dependency>
    <groupId>im.mak</groupId>
    <artifactId>paddle</artifactId>
    <version>1.0.0-rc9</version>
</dependency>

Gradle

Groovy DSL:

implementation 'im.mak:paddle:1.0.0-rc9'

Kotlin DSL:

compile("im.mak:paddle:1.0.0-rc9")

Simple usage

import im.mak.paddle.Account;
public class Main {
    public static void main(String[] args) {

        // Create two accounts.
        // At the time of creation first account,
        // Paddle automatically downloaded and started Waves Node in Docker container!
        Account alice = new Account(10_00000000); // account with 10 Waves
        Account bob = new Account();              // account with no Waves

        // Alice sends 3 Waves to Bob
        // Paddle waits until the Transfer transaction appears in blockchain
        alice.transfers(t -> t.to(bob).amount(3_00000000));

        System.out.println( bob.balance() ); // 300000000
        
        // When the program ends, Paddle will automatically turn off the Docker container
    }
}

Example with JUnit 5

import im.mak.paddle.Account;
import org.junit.jupiter.api.*;

import static org.junit.jupiter.api.Assertions.assertEquals;

class FirstTest {

    private Account alice, bob;
    private String assetId;

    @Test
    void canSendSmartAsset() {
        alice = new Account(10_00000000L);
        bob = new Account();

        assetId = alice.issues(a -> a
                .name("My Asset")
                .quantity(100)
                .script("2 * 2 == 4")
        ).getId().toString();

        alice.transfers(t -> t
                .to(bob)
                .amount(42)
                .asset(assetId)
        );
        
        assertEquals(42, bob.balance(assetId));
    }
}

Test lifecycle

Paddle is framework agnostic, i.e. Paddle can be used independently, or with JUnit, TestNG and any other test framework familiar to you.

But in general, any test consists of the following steps:

  1. run or connect to node;
  2. create test accounts;
  3. send some transactions;
  4. perform assertions;
  5. shutdown docker node, if it’s been used in step 1.

Steps 1 and 5 are performed automatically by Paddle.

Paddle configuration

Paddle needs some Waves node to execute test scenarios. By default, Paddle starts a node in a Docker container, but it’s possible to connect to any existing node.

The behaviour is set by parameters of selected profile, which can be declared in paddle.conf file.
The file paddle.conf can be created either in the project root or in the resources folder.

Pre-configured profiles

Paddle has predefined profiles, that are enough for most purposes:

Custom profiles

In the paddle.conf you can create your own profiles:

paddle.profile = my-profile
paddle.my-profile {
    api-url = "http://localhost:8080/"
    chain-id = D
    faucet-seed = some seed text
}
paddle.my-docker-profile = ${paddle.my-profile} {
    docker-image = "my-custom-image:latest"
    faucet-seed = another seed text
    auto-shutdown = true
}

In this example, when using my-profile, Paddle will connect to an already running local node.
And with my-docker-profile Paddle will launch a node container, because the docker-image field is specified.

${paddle.my-profile} means that my-docker-profile is inherited from the my-profile profile with additional parameters.

Note! Your custom docker image must expose port 6869 for REST API.

Run node in Docker

Default official image

If the docker profile is selected, then to start the node, just create an account or refer to the node instance:

import im.mak.paddle.Account;
import static im.mak.paddle.Node.node;

Account alice = new Account(100_00000000); // account with initial balance
// OR
node().height();

Paddle will start the node automatically!

Paddle requires a faucet account - this account is available as node().faucet() field of the Node instance.
It’s used as a bank for initial balances of other test accounts. When creating any new account, Waves tokens for its initial balance are transferred from the faucet account.

Paddle turns off the node container itself when all tests are finished. But if tests are interrupted urgently, then the container will most likely remain working, and you will have to turn it off yourself.

Node instance

Account

In Paddle, Account is an actor of your test. It has all the Waves account information and can send transactions.

To create new account:

Account alice = new Account(10_00000000L);

Optionally, you can specify seed phrase, otherwise it will be randomly generated.

Also optionally, you can set initial Waves balance, otherwise account will not have Waves tokens at start.
Technically, when you specify initial balance, “rich” account sends Transfer transaction to the created account.

Retrieving information about account

Account can provide seed phrase, private and public keys, address. Account can check if it’s scripted:

alice.seed();
alice.privateKey();
alice.publicKey();
alice.address();

alice.isSmart();

Account can get Waves or asset balance and read entries from its data storage:

alice.balance();        // balance in Waves
alice.balance(assetId); // balance in some asset
alice.nft();            // list of non-fungible tokens on this account

alice.data();           // collection of all entries in account data storage
alice.dataByKey(key);   // entry of unknown type by specified key

alice.dataBin(key);     // binary entry by specified key
alice.dataBool(key);    // boolean entry by specified key
alice.dataInt(key);     // integer entry by specified key
alice.dataStr(key);     // string entry by specified key

Signing data and sending transactions

Account can sign any bytes and send transactions:

alice.sign(tx.getBodyBytes());

alice.issues(...);
alice.setsScript(...);
alice.invokes(...);
// and etc...

Sending a transaction, you can specify only the fields important for your scenario - in most cases all other fields will be set by default or calculated automatically.
For example, you don’t have to specify asset name and description for Issue transaction:

alice.issues(a -> a.quantity(1000).decimals(0));
// only the number of tokens and decimals are specified here

Also, transaction fee will be calculated automatically too! Exceptions at now: sponsored fee in tokens and InvokeScript transactions with smart assets in ScriptTransfers of dApp contract.

You don’t need sign transactions explicitly - Paddle does it automatically.
You don’t need wait when transactions will be added to blockchain - Paddle does it automatically.

Creating dApp and smart account

To create dApp or smart asset, you can provide script source from file:

alice.setsScript(s -> s.script(Script.fromFile("wallet.ride")));
alice.issues(a -> a.script(Script.fromFile("fixed-price.ride")));

Or set script code directly as string:

alice.setsScript(s -> s.script("sigVerify(tx.bodyBytes, tx.proofs[0], tx.senderPublicKey)"));
alice.issues(a -> a.script("true"));

In both cases Paddle will compile your script automatically.

Assertions

Transaction

Each account action returns an instance of the resulting transaction from blockchain.

String assetId = alice.issues(a -> a.quantity(1000)).getId().toString();

assertEquals(1000, alice.balance(assetId));

State changes of InvokeScript transaction

If connected node stores state changes of InvokeScript transactions (depends of the node config), you can check it:

String txId = bob.invokes(i -> i.dApp(alice)).getId().toString();

StateChanges changes = node().api.stateChanges(txId);

assertAll(
    () -> assertEquals(1, changes.data.size()),
    () -> assertEquals(bob.address(), changes.data.get(0).key),
    () -> assertEquals(100500, changes.data.get(0).asInteger())
);

Transactions rejection

If you expect that some transaction will return error and will not be in blockchain, you can check it by catching the NodeError exception.

For example, how it can look with JUnit 5:

NodeError error = assertThrows(NodeError.class, () ->
        bob.invokes(i -> i.dApp(alice).function("deposit").payment(500, assetId))
);

assertTrue(error.getMessage().contains("can accept payment in waves tokens only!"));

Other features

Waitings

Height

Paddle allows to wait for the growth of the height of N blocks

node().waitNBlocks(2);

or until the height of the blockchain reaches the specified

node().waitForHeight(100);

The both methods have “soft” timeouts. This means that they continue to wait until the height rises with the expected frequency. The expected frequency is a triple value of the block-interval field in Paddle config file, but can be redefined by optional argument:

node().waitNBlocks(2, waitingInSeconds);
node().waitForHeight(100, waitingInSeconds);

Transaction

Also Paddle can wait until transaction with specified id is in blockchain:

node().waitForTransaction(txId);

The timeout value is specified in block-interval field in Paddle config file, but can be redefined by optional argument.

Asynchronous actions

To save execution time (or for other reasons in specific cases) it would be great to be able to perform some actions asynchronously.

For example, we want create some test account and each of them will issue asset:

Account alice = new Account(1_00000000);
Account bob = new Account(1_00000000);
Account carol = new Account(1_00000000);
alice.issues(a -> a.name("Asset 1"));
bob.issues(a -> a.name("Asset 2"));
carol.issues(a -> a.name("Asset 3"));

These 6 transactions will be sent consecutively. But with Async.async() their asynchronous execution will be three times faster:

async(
    () -> {
        Account alice = new Account(1_00000000);
        alice.issues(a -> a.name("Asset 1"));
    }, () -> {
        Account bob = new Account(1_00000000);
        bob.issues(a -> a.name("Asset 2"));
    }, () -> {
        Account carol = new Account(1_00000000);
        carol.issues(a -> a.name("Asset 3"));
    }
);

At now, all operations will be executed in three threads, and only dependent transactions will be sent consecutively.

Async waits for all operations to be completed.

RSA Encryption

Function rsaVerify() in Ride checks that the RSA signature is valid, i.e. it was created by the owner of the public key.

With Paddle you can create a signature like this:

Rsa rsa = new Rsa(); // generated private and public keys pair
byte[] prKey = rsa.privateKey();
byte[] pubKey = rsa.publicKey();
// signature created by the private key with SHA256 algorithm
byte[] signature = rsa.sign(HashAlg.SHA256, "Hello!".getBytes());

HashAlg contains all hashing algorithms supported in Ride:

Merkle Tree

Function checkMerkleProof() in Ride checks that the data is part of the Merkle tree.

With Paddle you can create such a Merkle tree and get data proofs:

List<byte[]> leafs = asList("one".getBytes(), "two".getBytes(), "three".getBytes());
MerkleTree tree = new MerkleTree(leafs);
byte[] rootHash = tree.rootHash();
byte[] proof = tree.proofByLeaf("two".getBytes()).get();

What next?

See tests in the repository for examples how the Paddle can be used.

paddle-example - project boilerplate with example of Waves dApp and tests with Paddle.

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