izumi.distage.testkit.services.scalatest.dstest

Serialises ScalaTest test events on a per-suite, per-test basis so that downstream reporters see a strict TestStarting → terminator → TestStarting → terminator … sequence within each suite.

This is required by several downstream ScalaTest reporters that pair-walk events within a suite and either throw RuntimeException("unexpected …") or otherwise corrupt their output when concurrent intra-suite test events interleave (distage testkit runs tests with parallelTests = Parallelism.Unlimited by default — see TestConfig.scala:79-82). The exception is silently swallowed by org.scalatest.CatchReporter:34-44, so the failure mode is "per-suite output file silently absent" rather than a crash — observed as JUnit XML test undercount.

Reporters that REQUIRE this serialisation (pair-walkers):

• org.scalatest.tools.JUnitXmlReporter.processTest:284-345 (throws on stray test events)
• org.scalatest.tools.XmlReporter:129-172, 467-469 (same pattern)
• org.scalatest.tools.DashboardReporter.SuiteRecord.toXml:720-738 and TestRecord.addEvent:764-779 (throws on terminator without preceding start)

Reporters that BENEFIT (better-grouped output) but do not strictly require it:

• org.scalatest.tools.HtmlReporter:1027-1083 — counter-style aggregation, tolerates interleaving but renders nicer with linearised events
• Intellij's reporter (the original motivation for this class)

Reporters that are unaffected (per-event sinks):

• All StringReporter-family sinks (PrintReporter, FileReporter, StandardOutReporter, StandardErrReporter)
• MemoryReporter, FilterReporter, SbtDispatchReporter, SocketReporter, XmlSocketReporter