net/http: ignore ECONNRESET errors in TestTransportConcurrency on netbsd

The source of these errors is undiagnosed, but they have only been
observed on netbsd builders (on a variety of architectures).

Tested manually by injecting this code into the test's handler:

		if mrand.Intn(4) == 0 {
			if conn, _, err := w.(Hijacker).Hijack(); err == nil {
				conn.(*net.TCPConn).SetLinger(0)
				conn.Close()
				return
			}
		}

and temporarily disabling the 'runtime.GOOS' part of the condition.

For #52168.

Change-Id: I10965803e5a0d493ac4a000575de8b5f0266989c
Reviewed-on: https://go-review.googlesource.com/c/go/+/398635
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/src/net/http/transport_test.go b/src/net/http/transport_test.go
index 440d6b969b..84065c7085 100644
--- a/src/net/http/transport_test.go
+++ b/src/net/http/transport_test.go
@@ -2099,17 +2099,21 @@ func TestTransportConcurrency(t *testing.T) {
 			for req := range reqs {
 				res, err := c.Get(ts.URL + "/?echo=" + req)
 				if err != nil {
-					t.Errorf("error on req %s: %v", req, err)
+					if runtime.GOOS == "netbsd" && strings.HasSuffix(err.Error(), ": connection reset by peer") {
+						// https://go.dev/issue/52168: this test was observed to fail with
+						// ECONNRESET errors in Dial on various netbsd builders.
+						t.Logf("error on req %s: %v", req, err)
+						t.Logf("(see https://go.dev/issue/52168)")
+					} else {
+						t.Errorf("error on req %s: %v", req, err)
+					}
 					wg.Done()
 					continue
 				}
 				all, err := io.ReadAll(res.Body)
 				if err != nil {
 					t.Errorf("read error on req %s: %v", req, err)
-					wg.Done()
-					continue
-				}
-				if string(all) != req {
+				} else if string(all) != req {
 					t.Errorf("body of req %s = %q; want %q", req, all, req)
 				}
 				res.Body.Close()