cache compressed certificate chains

fixes #227

crypto/cert_cache_test.go

@@ -0,0 +1,39 @@
+package crypto
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Certificate cache", func() {
+	BeforeEach(func() {
+		compressedCertsCache = map[uint64][]byte{}
+	})
+
+	It("gives a compressed cert", func() {
+		chain := [][]byte{{0xde, 0xca, 0xfb, 0xad}}
+		expected, err := compressChain(chain, nil, nil)
+		Expect(err).NotTo(HaveOccurred())
+		compressed, err := getCompressedCert(chain, nil, nil)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(compressed).To(Equal(expected))
+	})
+
+	It("gets the same result multiple times", func() {
+		chain := [][]byte{{0xde, 0xca, 0xfb, 0xad}}
+		compressed, err := getCompressedCert(chain, nil, nil)
+		Expect(err).NotTo(HaveOccurred())
+		compressed2, err := getCompressedCert(chain, nil, nil)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(compressed).To(Equal(compressed2))
+	})
+
+	It("stores cached values", func() {
+		Expect(compressedCertsCache).To(HaveLen(0))
+		chain := [][]byte{{0xde, 0xca, 0xfb, 0xad}}
+		compressed, err := getCompressedCert(chain, nil, nil)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(compressedCertsCache).To(HaveLen(1))
+		Expect(compressedCertsCache[3838929964809501833]).To(Equal(compressed))
+	})
+})