implement a function to close the h2quic.RoundTripper

h2quic.RoundTripper.Close() closes all QUIC connections that this
roundtripper has used.

h2quic/roundtrip_test.go

@@ -13,11 +13,19 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-type mockRoundTripper struct{}
+type mockClient struct {
+	closed bool
+}
 
-func (m *mockRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+func (m *mockClient) RoundTrip(req *http.Request) (*http.Response, error) {
 	return &http.Response{Request: req}, nil
 }
+func (m *mockClient) Close() error {
+	m.closed = true
+	return nil
+}
+
+var _ roundTripCloser = &mockClient{}
 
 type mockBody struct {
 	reader   bytes.Reader
@@ -170,4 +178,23 @@ var _ = Describe("RoundTripper", func() {
 			Expect(req1.Body.(*mockBody).closed).To(BeTrue())
 		})
 	})
+
+	Context("closing", func() {
+		It("closes", func() {
+			rt.clients = make(map[string]roundTripCloser)
+			cl := &mockClient{}
+			rt.clients["foo.bar"] = cl
+			err := rt.Close()
+			Expect(err).ToNot(HaveOccurred())
+			Expect(len(rt.clients)).To(BeZero())
+			Expect(cl.closed).To(BeTrue())
+		})
+
+		It("closes a RoundTripper that has never been used", func() {
+			Expect(len(rt.clients)).To(BeZero())
+			err := rt.Close()
+			Expect(err).ToNot(HaveOccurred())
+			Expect(len(rt.clients)).To(BeZero())
+		})
+	})
 })