test: wait for provisioning before driving the poller

CHANGELOG.md

@@ -6,6 +6,16 @@ All notable changes to this project are documented here. The format follows
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed a flaky `TestPollerTracksExit` (#38). `provision` sets the sandbox's terminal condition
+  and only then returns, and the entry's `done` channel is closed after that — so a test that
+  waited for `BackendReady` and immediately drove `pollOnce` could land in the window where the
+  entry still counted as in flight, which `pollOnce` skips by design. No transition happened and
+  the test timed out. The affected tests now wait for the provisioning task itself; the same
+  window also let `TestPollerKeepsProvisioningFailure` pass for the wrong reason. Test-only —
+  in production the next 2 s poll covers the window.
+
 ## [0.2.9] - 2026-08-08
 
 ### Fixed

internal/grpcsvc/create_test.go

@@ -83,6 +83,38 @@ func createRequest() *computev1.CreateSandboxRequest {
 	}
 }
 
+// waitForProvisioning blocks until the test sandbox's provisioning task has
+// finished.
+//
+// Reaching a terminal condition is NOT enough to know that: provision() sets
+// the condition and only then returns, and the goroutine closes the entry's
+// done channel after that. So there is a window in which BackendReady (or
+// ProvisioningFailed) is already observable while the entry still counts as
+// in flight — and pollOnce skips in-flight entries by design. A test that
+// drives pollOnce inside that window sees no transition at all.
+//
+// Any test that calls srv.pollOnce after a create must wait here first, unless
+// it is deliberately polling mid-provision like
+// TestPollerSkipsInFlightProvisioning.
+func waitForProvisioning(t *testing.T, srv *Server) {
+	t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for {
+		srv.mu.Lock()
+		e, ok := srv.sandboxes[testSandboxID]
+		srv.mu.Unlock()
+		// done is set once at create and never reassigned, so reading it
+		// off the entry outside the lock is safe.
+		if ok && e.provisionDone() {
+			return
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("provisioning task did not finish")
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+}
+
 // waitForCondition polls until the test sandbox's condition reason matches.
 func waitForCondition(t *testing.T, srv *Server, reason string) condition {
 	t.Helper()

internal/grpcsvc/reconcile_test.go

@@ -125,6 +125,9 @@ func TestPollerTracksExit(t *testing.T) {
 		t.Fatal(err)
 	}
 	waitForCondition(t, srv, reasonBackendReady)
+	// The poll below only does anything once the entry is no longer in
+	// flight, and BackendReady becomes visible before that.
+	waitForProvisioning(t, srv)
 
 	// Subscribe before the transition to capture the Warning event.
 	subID, events := srv.hub.subscribe()
@@ -220,6 +223,9 @@ func TestPollerKeepsProvisioningFailure(t *testing.T) {
 		t.Fatal(err)
 	}
 	waitForCondition(t, srv, reasonProvisioningFailed)
+	// Without this the poll can skip the entry as still in flight, and the
+	// assertion below would hold for the wrong reason.
+	waitForProvisioning(t, srv)
 
 	// The VM never existed; polling must keep the original failure.
 	srv.pollOnce(context.Background())