Neo-Test

This repo contains tools and libraries for automating Neo smart contract tests.

Neo Test Harness

This library several types needed for automated testing of Neo smart contracts.

TestApplicationEngine - Subclass of Neo ApplicationEngine that can run independently of a running Neo blockchain. Heavily based off the Smart Contract Debugger's DebugApplicationEngine.
CheckpointFixture - class to manage the use of a Neo-Express checkpoint as a shared resource for multiple tests. Designed to work with xUnit's Class Fixture feature but can be used with other test frameworks if desired
Extensions - a set of extension methods used to make it easier to interact with and generate execution scripts for smart contracts.
- GetContract<T> - retrieve the ContractState value for a given contract type
- GetContractStorages<T> - retrieve the storage for a contract as a .NET IReadOnlyDictionary<ReadOnlyMemory[byte], StorageItem> for easy assertion
- Create/Load/ExecuteScript<T> - generate contract execution script from strongly typed LINQ expression and optionally load/execute it

Example:

// metadata used by CheckpointFixture to locate checkpoint file 
[CheckpointPath("checkpoints/contract-deployed.nxp3-checkpoint")]
public class ContractDeployedTests : IClassFixture<CheckpointFixture<ContractDeployedTests>>
{
    readonly CheckpointFixture fixture;

    // xUnit.NET provides CheckpointFixture instance via constructor injection
    public ContractDeployedTests(CheckpointFixture<ContractDeployedTests> fixture)
    {
        this.fixture = fixture;
    }

    [Fact]
    public void Can_register_domain()
    {
        // each test in the class retrieves a fresh IStore instance from the fixture
        using var store = fixture.GetCheckpointStore();
        using var snapshot = new SnapshotView(store);

        // Use GetContractStorages to ensure storage is empty 
        snapshot.GetContractStorages<Registrar>().Any().Should().BeFalse();

        // ExecuteScript converts the provided expression(s) into a Neo script
        // loads them into the engine and executes it 
        using var engine = new TestApplicationEngine(snapshot, ALICE);
        engine.ExecuteScript<Registrar>(c => c.register(DOMAIN_NAME, ALICE));

        // Assert test step omitted
    }

Neo Assertions

This library builds on the Fluent Assertions library and provides custom assertions for Neo VM StackItems, Neo StorageItems and NotifyEventArgs.

Examples:

[Fact]
public void Can_register_domain()
{
    // Test arrange and act steps omitted

    engine.State.Should().Be(VMState.HALT);
    engine.ResultStack.Should().HaveCount(1);
    // Assert StackItem as boolean
    engine.ResultStack.Peek(0).Should().BeTrue();

    // retrieve storages for a given contract as a IReadOnlyDictionary
    var storages = snapshot.GetContractStorages<Registrar>();

    byte[] DOMAIN_NAME = Neo.Utility.StrictUTF8.GetBytes("sample.domain");
    storages.TryGetValue(DOMAIN_NAME, out var item).Should().BeTrue();

    // Assert StorageItem as a Uint160 value
    UInt160 ALICE = "NhGxW6BtLRhFLqh2oWqeRpNj8aNzKybRoV".FromAddress();
    item!.Should().Be(ALICE);

    // Assert Notifications
    engine.Notifications.Should().HaveCount(1);
    engine.Notifications[0].Should()
        .BeSentBy(snapshot.GetContract<Registrar.Events>())
        .And
    // use LINQ expression to specify strongly-typed exepcted notification values
        .BeEquivalentTo<Registrar.Events>(c => c.Register("sample.domain", ALICE));
}

Neo Test Runner

While the Neo Test Harness and Assertions libraries described above are great, they are only available to C# Neo dApp developers. Developers building their contracts using other languages like Python, Java or Go can't use them. The Neo Test Runner is a stand-alone EXE, shipped as a .NET Tool that can execute test scripts against an emulated Neo blockchain environment and writes the results to the console in an easy-to-parse JSON format.

To install the test runner, use the dotnet tool install command:

> dotnet tool install Neo.Test.Runner -g

Example Command Execution:

> neo-test-runner register-sample-domain.neo-invoke.json --account bob --checkpoint contract-deployed.neoxp-checkpoint --express default.neo-express --storages registrar --nef-file src/bin/sc/registrar.nef

Example Output:

{
  "state": "HALT",
  "exception": null,
  "gasconsumed": "0.0869496",
  "logs": [],
  "notifications": [],
  "stack": [
    {
      "type": "Boolean",
      "value": true
    }
  ],
  "storages": [
    {
      "name": "registrar",
      "hash": "0xc6cf77e89ff11499717c7f2c83416e2c0273b2d6",
      "values": [
        {
          "key": "UmVnaXN0cmFy",
          "value": "iAKhsjONfqImOHWgs72sXPvwO4U="
        },
        {
          "key": "ZG9tYWluT3duZXJzc2FtcGxlLmRvbWFpbg==",
          "value": "o2rCWQljs56nfcn8JzEaqt4Ql08="
        }
      ]
    }
  ],
  "code-coverage": {
    "contract-hash": "0xc6cf77e89ff11499717c7f2c83416e2c0273b2d6",
    "debug-info-hash": "0xf69e5188632deb3a9273519efc86cb68da8d42b8",
    "hit-map": {
      "3": 0,
      "4": 0,
      "53": 0,
      "59": 0,
      "63": 1,
      "215": 1,
      "247": 1,
      // emits the hit count for every statement in the contract
    },
    "branch-map": {
      "14": "0-0",
      "63": "0-1",
      "258": "1-0",
      // emits the hit count for each branch  in the contract
    }
  }
}

Neo Build Tasks

For C# developers, the Neo.BuildTasks package includes multiple MSBuild tasks to make Neo smart contract development easier. These tasks include:

NeoCsc - run nccs C# contract compiler
NeoExpressBatch - run neoxp batch
NeoContractInterface - generate a C# interface from contract manifest for use in tests

Note: both NeoCsc and NeoExpressBatch tasks assume the associated .NET tool is installed either globally or locally. If installed both globally and locally, the locally installed version will be used.

These tasks can be enabled simply by adding a PackageReference with PrivateAssets="All" then setting MSBuild properties and/or items.

To enable NeoCsc task, set <NeoContractName> property to the name you want the contract to have. Typically, this is set to $(AssemblyName).
To enable NeoExpressBatch task, set <NeoExpressBatchFile> property to the path of the NeoExpress batch file you want to execute
To enable NeoContractInterface task, set a <NeoContractReference> item in your test project with a path to the contract project.

Example Contract .csproj file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <NeoContractName>$(AssemblyName)</NeoContractName>
    <NeoExpressBatchFile>..\express.batch</NeoExpressBatchFile>
    <Nullable>enable</Nullable>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Neo.SmartContract.Framework" Version="3.3.1" />
    <PackageReference Include="Neo.BuildTasks" Version="3.3.10-preview" PrivateAssets="All" />
  </ItemGroup>

</Project>

Example Contract Test .csproj file:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <IsPackable>false</IsPackable>
    <Nullable>enable</Nullable>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <NeoContractReference Include="..\src\registrar.csproj" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="coverlet.collector" Version="3.1.2" PrivateAssets="All" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
    <PackageReference Include="Neo.Assertions" Version="3.3.10-preview" />
    <PackageReference Include="Neo.BuildTasks" Version="3.3.10-preview" PrivateAssets="All" />
    <PackageReference Include="Neo.Test.Harness" Version="3.3.10-preview" />
    <PackageReference Include="xunit" Version="2.4.1" />
    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="All" />
  </ItemGroup>

</Project>

Example generated contract interface:

// CSharp 
[NeoTestHarness.Contract("Neo.Example.Nep17Token")]
interface Nep17Token
{
    System.Numerics.BigInteger balanceOf(Neo.UInt160 account);
    System.Numerics.BigInteger decimals();
    void deploy(bool update);
    void destroy();
    void disablePayment();
    void enablePayment();
    void onPayment(Neo.UInt160 from, System.Numerics.BigInteger amount, object? data);
    string symbol();
    System.Numerics.BigInteger totalSupply();
    bool transfer(Neo.UInt160 from, Neo.UInt160 to, System.Numerics.BigInteger amount, object? data);
    void update(byte[] nefFile, string manifest);
    bool verify();
    interface Events
    {
        void Transfer(Neo.UInt160 arg1, Neo.UInt160 arg2, System.Numerics.BigInteger arg3);
    }
}

Neo.Collector

For C# developers, the Neo.Collector package can be used to collect smart contract code coverage. By specifying "Neo code coverage" as the collector for a dotnet test run, the developer can get coverage information for the contracts in the popular Cobertura format.

For more details, see the code coverage documentation

devhawk/neo-test