Add test for deferrable

pkg/deferrable/deferrable_test.go

@@ -0,0 +1,37 @@
+package deferrable_test
+
+import (
+	"github.com/initialcapacity/go-streaming/pkg/deferrable"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"testing"
+)
+
+func TestDefer(t *testing.T) {
+	writer := ResponseWriterSpy{}
+	d := deferrable.New(&writer, "pickles")
+
+	value := d.Value()
+
+	assert.Equal(t, "pickles", value)
+	assert.True(t, writer.FlushCalled)
+}
+
+type ResponseWriterSpy struct {
+	FlushCalled bool
+}
+
+func (w *ResponseWriterSpy) Header() http.Header {
+	return map[string][]string{}
+}
+
+func (w *ResponseWriterSpy) Write([]byte) (int, error) {
+	return 0, nil
+}
+
+func (w *ResponseWriterSpy) WriteHeader(statusCode int) {
+}
+
+func (w *ResponseWriterSpy) Flush() {
+	w.FlushCalled = true
+}