Script Field's script doesn't see issue links created during unit test setup

[Dov Frankel]

I'm following the ScriptRunner template for configuring unit tests of my Script Field, which is working in Jira. I'm debugging the unit tests in IntelliJ using the sample project config that launches a local Jira instance. This is what my test looks like:

@RunWith(ScriptRunnerTestRunner)
class TestingEnvironmentFieldIT extends AbstractScriptFieldSpecification {

    //...

    def "Test Case Name"() {
        setup:
        def project = getTestProject()

        def issueParams = new IssueInputParametersImpl()
        issueParams.with {
            setProjectId(project.id)
            setIssueTypeId(issueTypeID)
            setReporterId(user.name)
            setSummary("test ticket")
        }

        when:
        def createValidationResult = issueService.validateCreate(currentUser, issueParams)

        then:
        assert createValidationResult.isValid()

        when:
        def issue = (MutableIssue)issueService.create(currentUser, createValidationResult).issue
        assert issue.isCreated()

        def linkedTicket = // created during global setup
        assert linkedTicket != null
        issueLinkManager.createIssueLink(linkedTicket.getId(), issue.getId(), testingLinkType.getId(), 0L, currentUser)

        then:
        def fieldValue = issue.getCustomFieldValue(fieldUnderTest)
        assert fieldValue.contains("Expected Value")
    }
}  

And this is the code in my Script Field that I've stripped down to demonstrate the issue:

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.Issue

def linkManager = ComponentAccessor.getIssueLinkManager()
def linkedIssues = linkManager.getInwardLinks(((Issue)issue).getId())
return linkedIssues.collect { it.getSourceObject().getKey() }.join(", ")

I get an empty string back on the final assertion line. I'm confident the code to get the issue links works, and I'm even pretty confident the code to create issue links works, since I've tried querying the links in the unit test code and I see that the links are created. Why aren't they coming back in my unit test?