README.md

Introduction to parallel execution in Spock

In this part you will learn and exercise parallel execution feature for Spock.

First, familiarize yourself with tests in this module.

No parallelization

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

Parallel execution

• Enable parallel execution in SpockConfig.groovy

runner {
    parallel {
        enabled true
    }
}

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

Check other reports created by Gradle:

• HTML report
• XML report

Execution modes

• two execution modes
  • SAME_THREAD
  • CONCURRENT
• defined
  • for specifications (test classes) by runner.parallel.defaultSpecificationExecutionMode
  • for features (tests methods) by runner.parallel.defaultExecutionMode

Sample configuration:

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
        defaultSpecificationExecutionMode ExecutionMode.SAME_THREAD
        defaultExecutionMode ExecutionMode.SAME_THREAD
    }
}

Sequential Execution (SAME_THREAD Specifications, SAME_THREAD Features)

• Set

runner {
    parallel {
        enabled false
    }
}

• or

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
        defaultSpecificationExecutionMode ExecutionMode.SAME_THREAD
        defaultExecutionMode ExecutionMode.SAME_THREAD
    }
}

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

CONCURRENT Specifications, CONCURRENT Features

• Set

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
    }
}

• or

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
        // ExecutionMode.CONCURRENT is a default value
        // of defaultSpecificationExecutionMode and defaultExecutionMode
        defaultSpecificationExecutionMode ExecutionMode.CONCURRENT
        defaultExecutionMode ExecutionMode.CONCURRENT
    }
}

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

CONCURRENT Specifications, SAME_THREAD Features

• Set

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
        defaultSpecificationExecutionMode ExecutionMode.CONCURRENT
        defaultExecutionMode ExecutionMode.SAME_THREAD
    }
}

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

SAME_THREAD Specifications, CONCURRENT Features

• Set

import org.spockframework.runtime.model.parallel.ExecutionMode

runner {
    parallel {
        enabled true
        defaultSpecificationExecutionMode ExecutionMode.SAME_THREAD
        defaultExecutionMode ExecutionMode.CONCURRENT
    }
}

• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports

Isolated execution

• Enable parallel execution (concurrent features, concurrent specifications)
• Create a copy of class A and name it C
• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport
• Check reports
• Add @Isolated (spock.lang.Isolated) annotation to C class
• Run test again ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport and check reports

Parallel thread pool

Supported options:

• dynamic(BigDecimal factor)
• dynamicWithReservedProcessors(BigDecimal factor, int reservedProcessors)
• fixed(int parallelism)
• custom(int parallelism, int minimumRunnable, int maxPoolSize, int corePoolSize, int keepAliveSeconds) (docs)

Default: dynamicWithReservedProcessors(1.0, 2) (Runtime.getRuntime().availableProcessors() * 1.0 - 2)

Example thread pool configuration:

runner {
    parallel {
        enabled true
        fixed(4)
    }
}

Check number of available processors:

jshell print-available-processors.jsh

Sample output:

Runtime.getRuntime().availableProcessors() = 10

• Add test case to class A

def "test 3"() {
    sleep SLEEP_DURATION

    expect:
    true

    where:
    data << (1..20)
}

• Remove class C
• Run tests ./gradlew --rerun-tasks :part1.0-introduction:test :part1.0-introduction:createTestsExecutionReport -PtotalTimeOfAllTests=false
• Check reports
• Configure a thread pool of your choice, run tests and check reports
• Randomize duration of tests. In test test 3 replace SLEEP_DURATION with new Random().nextLong(50, 250). Run tests and check reports.

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