add two tests

Signed-off-by: Jeremy Krach <jkrach@pinterest.com>

utils/configuration_test.go

@@ -21,9 +21,11 @@ import (
 const envPrefix = "NOTARY_TESTING_ENV_PREFIX"
 
 const (
-	Cert = "../fixtures/notary-server.crt"
-	Key  = "../fixtures/notary-server.key"
-	Root = "../fixtures/root-ca.crt"
+	Cert   = "../fixtures/notary-server.crt"
+	Key    = "../fixtures/notary-server.key"
+	Root   = "../fixtures/root-ca.crt"
+	NoCert = "../fixtures/nonexistant.crt"
+	NoKey  = "../fixtures/nonexistant.key"
 )
 
 // initializes a viper object with test configuration
@@ -417,6 +419,38 @@ func TestParseTLSWithTLS(t *testing.T) {
 	require.Equal(t, tlsConfig.ClientAuth, tls.RequireAndVerifyClientCert)
 }
 
+// Verifies that the GetCertificate function on the TLS Config object gives us what we expect
+func TestTLSGetCertificate(t *testing.T) {
+	config := configure(fmt.Sprintf(`{
+		"server": {
+			"tls_cert_file": "%s",
+			"tls_key_file": "%s",
+			"client_ca_file": "%s"
+		}
+	}`, Cert, Key, Root))
+
+	tlsConfig, err := ParseServerTLS(config, false)
+	require.NoError(t, err)
+
+	certificate, err := tlsConfig.GetCertificate(nil)
+	require.NoError(t, err)
+
+	require.Equal(t, tlsConfig.Certificates[0], *certificate)
+}
+
+// Checks the helper function that reloads the certificate with some bad cases (File DNE, mismatched key/cert)
+func TestLoadCertificateFailures(t *testing.T) {
+	// Cert DNE
+	_, err := loadCertificate(NoCert, Key)
+	require.Error(t, err)
+	// Key DNE
+	_, err = loadCertificate(Cert, NoKey)
+	require.Error(t, err)
+	// Mismatched
+	_, err = loadCertificate(Cert, Cert)
+	require.Error(t, err)
+}
+
 func TestParseTLSWithTLSRelativeToConfigFile(t *testing.T) {
 	currDir, err := os.Getwd()
 	require.NoError(t, err)