Support go 1.16

Signed-off-by: Julien Pivotto <[email protected]>

Author: Julien Pivotto

.circleci/config.yml

@@ -66,5 +66,8 @@ workflows:
     - test:
         name: go-1-15
         go_version: "1.15"
+    - test:
+        name: go-1-16
+        go_version: "1.16"
         # Style is only checked against the latest supported Go version.
         run_style: true

.travis.yml

@@ -1,5 +1,5 @@
 # Common
-[![Build Status](https://travis-ci.org/prometheus/common.svg)](https://travis-ci.org/prometheus/common)
+[![circleci](https://circleci.com/gh/prometheus/common/tree/master.svg?style=shield)][circleci]
 
 This repository contains Go libraries that are shared across Prometheus
 components and libraries. They are considered internal to Prometheus, without

README.md

@@ -513,8 +513,17 @@ func TestTLSConfig(t *testing.T) {
 		t.Fatalf("Unexpected client certificate result: \n\n%+v\n expected\n\n%+v", cert, clientCertificate)
 	}
 
-	// non-nil functions are never equal.
+	// tlsConfig.rootCAs.LazyCerts contains functions getCert() in go 1.16, which are
+	// never equal. Compare the Subjects instead.
+	if !reflect.DeepEqual(tlsConfig.RootCAs.Subjects(), expectedTLSConfig.RootCAs.Subjects()) {
+		t.Fatalf("Unexpected RootCAs result: \n\n%+v\n expected\n\n%+v", tlsConfig.RootCAs.Subjects(), expectedTLSConfig.RootCAs.Subjects())
+	}
+	tlsConfig.RootCAs = nil
+	expectedTLSConfig.RootCAs = nil
+
+	// Non-nil functions are never equal.
 	tlsConfig.GetClientCertificate = nil
+
 	if !reflect.DeepEqual(tlsConfig, expectedTLSConfig) {
 		t.Fatalf("Unexpected TLS Config result: \n\n%+v\n expected\n\n%+v", tlsConfig, expectedTLSConfig)
 	}