log/syslog: report hostname mismatch error details

The existing error log in check doesn't report the got/want hostname
even though that can be the cause of the error. Log those as well.

While we're here, also report os.Hostname() errors.

For #59568.

Change-Id: Ia277f85eddc541f2e78d719bc731db24e4513754
Reviewed-on: https://go-review.googlesource.com/c/go/+/483915
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/log/syslog/syslog_test.go b/src/log/syslog/syslog_test.go
index c7a5bfbd7b..cec225f751 100644
--- a/src/log/syslog/syslog_test.go
+++ b/src/log/syslog/syslog_test.go
@@ -270,7 +270,7 @@ func TestDial(t *testing.T) {
 func check(t *testing.T, in, out, transport string) {
 	hostname, err := os.Hostname()
 	if err != nil {
-		t.Error("Error retrieving hostname")
+		t.Errorf("Error retrieving hostname: %v", err)
 		return
 	}
 
@@ -290,9 +290,12 @@ func check(t *testing.T, in, out, transport string) {
 	var pid int
 	tmpl := fmt.Sprintf("<%d>%%s %%s syslog_test[%%d]: %s\n", LOG_USER+LOG_INFO, in)
 	n, err := fmt.Sscanf(out, tmpl, &timestamp, &parsedHostname, &pid)
-	if n != 3 || err != nil || hostname != parsedHostname {
+	if n != 3 || err != nil {
 		t.Errorf("Got %q, does not match template %q (%d %s)", out, tmpl, n, err)
 	}
+	if hostname != parsedHostname {
+		t.Errorf("Hostname got %q want %q in %q", parsedHostname, hostname, out)
+	}
 }
 
 func TestWrite(t *testing.T) {