Look up environment variables and determine if they are set or not instead of checking the value

contrib/dendrite-demo-i2p/main_i2p.go

@@ -44,6 +44,7 @@ import (
 
 var sam, err = goSam.NewClient(*samAddr)
 
+// Dial a network connection to an I2P server or a unix socket. Fail for clearnet addresses.
 func Dial(network, addr string) (net.Conn, error) {
 	if err != nil {
 		return nil, err

contrib/dendrite-demo-i2p/main_test.go

@@ -14,9 +14,10 @@ import (
 // Generate HTML with coverage: go tool cover -html=/somewhere/where/there/is/integrationcover.out -o cover.html
 // Source: https://dzone.com/articles/measuring-integration-test-coverage-rate-in-pouchc
 func TestMain(t *testing.T) {
-	if os.Getenv("CI") != "" {
+	if _, ex := os.LookupEnv("CI"); ex {
 		t.Skip("skipping test, as no TOR/I2P client is available")
 	} else {
+		t.Log("running locally, continuing with tests")
 		var (
 			args []string
 		)

contrib/dendrite-demo-tor/main_test.go

@@ -14,9 +14,10 @@ import (
 // Generate HTML with coverage: go tool cover -html=/somewhere/where/there/is/integrationcover.out -o cover.html
 // Source: https://dzone.com/articles/measuring-integration-test-coverage-rate-in-pouchc
 func TestMain(t *testing.T) {
-	if os.Getenv("CI") != "" {
+	if _, ex := os.LookupEnv("CI"); ex {
 		t.Skip("skipping test, as no TOR/I2P client is available")
 	} else {
+		t.Log("running locally, continuing with tests")
 		var (
 			args []string
 		)

contrib/dendrite-demo-tor/main_tor.go

@@ -43,6 +43,7 @@ import (
 var t, terr = tor.Start(context.Background(), nil)
 var tdialer, tderr = t.Dialer(context.TODO(), nil)
 
+// Dial either a unix socket address, or connect to a remote address over Tor. Always uses Tor.
 func Dial(network, addr string) (net.Conn, error) {
 	if terr != nil {
 		return nil, terr