@Rule
    public SetSystemProperties sysProp = new SetSystemProperties()

    def "set system properties"() {
        when:
        systemPropertiesInstaller.setSystemPropertiesFrom(loadedGradleProperties)

        then:
        "userSystemValue" == System.getProperty("userSystemProp")
        "userSystemValue2" == System.getProperty("userSystemProp2")
    }

import org.gradle.internal.service.scopes.Scope;
import org.gradle.internal.service.scopes.ServiceScope;

@ServiceScope(Scope.Build.class)
public interface SystemPropertiesInstaller {

    void setSystemPropertiesFrom(GradleProperties gradleProperties);

    ) {
        this.environmentChangeTracker = environmentChangeTracker;
        this.startParameter = startParameter;
        this.gradleInternal = gradleInternal;
    }

    @Override
    public void setSystemPropertiesFrom(GradleProperties gradleProperties) {
        // TODO:configuration-cache What happens when a system property is set from a Gradle property and

            MutableGradleProperties loadedProperties = propertiesLoader.loadGradleProperties(settingsDir);

            if (setSystemProperties) {
                systemPropertiesInstaller.setSystemPropertiesFrom(loadedProperties);
            }

            Map<String, Object> projectProperties = projectPropertiesLoader.loadProjectProperties();
            loadedProperties.updateOverrideProperties(projectProperties);