diff --git a/cmd/sdrd/phase_snapshot_test.go b/cmd/sdrd/phase_snapshot_test.go
new file mode 100644
index 0000000..10a217d
--- /dev/null
+++ b/cmd/sdrd/phase_snapshot_test.go
@@ -0,0 +1,18 @@
+package main
+
+import "testing"
+
+func TestPhaseSnapshotSetGet(t *testing.T) {
+	snap := &phaseSnapshot{}
+	state := phaseState{}
+	state.surveillance.NoiseFloor = -91
+	state.refinementInput.SampleRate = 2048000
+	snap.Set(state)
+	got := snap.Snapshot()
+	if got.surveillance.NoiseFloor != -91 {
+		t.Fatalf("unexpected noise floor: %v", got.surveillance.NoiseFloor)
+	}
+	if got.refinementInput.SampleRate != 2048000 {
+		t.Fatalf("unexpected sample rate: %v", got.refinementInput.SampleRate)
+	}
+}