diff --git a/api/stream/once_test.go b/api/stream/once_test.go
new file mode 100644
index 0000000..53ec08d
--- /dev/null
+++ b/api/stream/once_test.go
@@ -0,0 +1,43 @@
+package stream
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Execute(t *testing.T) {
+	executeOnce := once{}
+	execution := make(chan struct{})
+	fExecute := func() {
+		execution <- struct{}{}
+	}
+	go executeOnce.Do(fExecute)
+	go executeOnce.Do(fExecute)
+
+	select {
+	case <-execution:
+		// expected
+	case <-time.After(100 * time.Millisecond):
+		t.Fatal("fExecute should be executed once")
+	}
+
+	select {
+	case <-execution:
+		t.Fatal("should only execute once")
+	case <-time.After(100 * time.Millisecond):
+		// expected
+	}
+
+	assert.False(t, executeOnce.mayExecute())
+
+	go executeOnce.Do(fExecute)
+
+	select {
+	case <-execution:
+		t.Fatal("should only execute once")
+	case <-time.After(100 * time.Millisecond):
+		// expected
+	}
+}