add new EndOfTestResults event

Summary: It would be useful to debug issues like S469843 where test command is not finishing.

Reviewed By: samkevich

Differential Revision: D66479916

fbshipit-source-id: d195541811502a54c1a0e77772f6a0c95449876f

app/buck2_data/data.proto

@@ -309,9 +309,17 @@ message InstantEvent {
     // Just something for us to be able to easily propagate out internal
     // information. Used for testing.
     QuickUnstableE2eData unstable_e2e_data = 44;
+
+    /// Notification that execution of all tests for a given command is
+    /// finished.
+    EndOfTestResults end_of_test_results = 45;
   }
 }
 
+message EndOfTestResults {
+  int32 exit_code = 1;
+}
+
 // This should only be used as a mechanism to easily get information into the
 // event log for e2e tests.
 message QuickUnstableE2eData {

app/buck2_test/src/orchestrator.rs

@@ -65,6 +65,7 @@ use buck2_core::pattern::pattern_type::TargetPatternExtra;
 use buck2_core::provider::label::ConfiguredProvidersLabel;
 use buck2_core::target::configured_or_unconfigured::ConfiguredOrUnconfiguredTargetLabel;
 use buck2_core::target::configured_target_label::ConfiguredTargetLabel;
+use buck2_data::EndOfTestResults;
 use buck2_data::SetupLocalResourcesEnd;
 use buck2_data::SetupLocalResourcesStart;
 use buck2_data::TestDiscovery;
@@ -714,6 +715,7 @@ impl<'a> TestOrchestrator for BuckTestOrchestrator<'a> {
     }
 
     async fn end_of_test_results(&self, exit_code: i32) -> anyhow::Result<()> {
+        self.events.instant_event(EndOfTestResults { exit_code });
         self.results_channel
             .unbounded_send(Ok(ExecutorMessage::ExitCode(exit_code)))
             .map_err(|_| anyhow::Error::msg("end_of_tests was received twice"))?;