Web3j Unit¶
Web3j-unit is an extension to JUnit 5 which enables you to test solidity contracts like any other Java code. It allows you to test with both an embedded and dockerized Ethereum nodes, with out-of-the box support for Geth, Besu, and OpenEthereum nodes. A docker-compose network can also be configured easily for more complex setups.
Usage¶
First, let's add the gradle dependency.
repositories {
mavenCentral()
jcenter()
}
implementation "org.web3j:core:4.5.11"
testCompile "org.web3j:web3j-unit:4.5.11"
Using EVMTest annotation¶
Create a new test with the @EVMTest annotation. An embedded EVM is used by default. To use Geth or Besu pass the node type into the annotation: @EVMTest(NodeType.GETH) or @EVMTest(NodeType.BESU)
@EVMTest
public class GreeterTest {
}
Inject instance of Web3j, TransactionManager and ContractGasProvider in your test method.
@EVMTest
public class GreeterTest {
@Test
public void greeterDeploys(Web3j web3j, TransactionManager transactionManager, ContractGasProvider gasProvider ) {
}
}
Deploy your contract in the test.
@EVMTest
public class GreeterTest {
@Test
public void greeterDeploys(Web3j web3j, TransactionManager transactionManager, ContractGasProvider gasProvider) {
Greeter greeter = Greeter.deploy(web3j, transactionManager, gasProvider, "Hello EVM").send();
String greeting = greeter.greet().send();
assertEquals("Hello EVM", greeting);
}
}
Run the test!
Using EVMComposeTest annotation¶
Create a new test with the @EVMComposeTest annotation.
By default, it uses test.yml file in the project home, and runs web3j on service named node1 exposing the port 8545.
Can be customised to use specific docker-compose file, service name and port by @EVMComposeTest("src/test/resources/geth.yml", "ethnode1", 8080) Here, we connect to the service named ethnode1 in the src/test/resources/geth.yml docker-compose file which exposes the port 8080 for web3j to connect to.
@EVMComposeTest("src/test/resources/geth.yml", "ethnode1", 8080)
public class GreeterTest {
}
Inject instance of Web3j, TransactionManager and ContractGasProvider in your test method.
@EVMComposeTest("src/test/resources/geth.yml", "ethnode1", 8080)
public class GreeterTest {
@Test
public void greeterDeploys(Web3j web3j, TransactionManager transactionManager, ContractGasProvider gasProvider) {
}
}
Deploy your contract in the test.
@EVMComposeTest("src/test/resources/geth.yml", "ethnode1", 8080)
public class GreeterTest {
@Test
public void greeterDeploys(Web3j web3j, TransactionManager transactionManager, ContractGasProvider gasProvider) {
Greeter greeter = Greeter.deploy(web3j, transactionManager, gasProvider, "Hello EVM").send();
String greeting = greeter.greet().send();
assertEquals("Hello EVM", greeting);
}
}
Run the test!