diff --git a/header_test.go b/header_test.go
index 3f36a8c..dd9267f 100644
--- a/header_test.go
+++ b/header_test.go
@@ -10,6 +10,35 @@ import (
 	"testing"
 )
 
+func TestBufferStartEnd(t *testing.T) {
+	testBufferStartEnd(t, "", "", "")
+	testBufferStartEnd(t, "foobar", "foobar", "")
+
+	b := string(createFixedBody(199))
+	testBufferStartEnd(t, b, b, "")
+	for i := 0; i < 10; i++ {
+		b += "foobar"
+		testBufferStartEnd(t, b, b, "")
+	}
+
+	b = string(createFixedBody(400))
+	testBufferStartEnd(t, b, b, "")
+	for i := 0; i < 10; i++ {
+		b += "sadfqwer"
+		testBufferStartEnd(t, b, b[:200], b[len(b)-200:])
+	}
+}
+
+func testBufferStartEnd(t *testing.T, buf, expectedStart, expectedEnd string) {
+	start, end := bufferStartEnd([]byte(buf))
+	if string(start) != expectedStart {
+		t.Fatalf("unexpected start %q. Expecting %q. buf %q", start, expectedStart, buf)
+	}
+	if string(end) != expectedEnd {
+		t.Fatalf("unexpected end %q. Expecting %q. buf %q", end, expectedEnd, buf)
+	}
+}
+
 func TestResponseHeaderTrailingCRLFSuccess(t *testing.T) {
 	trailingCRLF := "\r\n\r\n\r\n"
 	s := "HTTP/1.1 200 OK\r\nContent-Type: aa\r\nContent-Length: 123\r\n\r\n" + trailingCRLF