From 9c62ef1243196a8a3a7dee5eef9b3b2f27e8d388 Mon Sep 17 00:00:00 2001 From: Dmitri Shuralyov Date: Fri, 28 Jul 2023 12:34:30 -0400 Subject: [PATCH] syscall: skip TestUnshare if there's nothing more to unshare Tests that need to use the internet are expected not to run when -short test flag is set, and the Go build system automatically catches when a test forgets that. It does this by unsharing all real network interfaces and leaving only a loopback interface in a new network namespace. TestUnshare tests that a process started with CLONE_NEWNET unshare flag has fewer network interfaces than before. Of course, if /proc/net/dev starts out with a single loopback interface, the test would fail with a false positive: === RUN TestUnshare exec_linux_test.go:139: Got 3 lines of output, want <3 --- FAIL: TestUnshare (0.00s) Give the test what it wants: a skip when the environment doesn't meet the minimum requirements for the test, and more useful log output if it fails. Change-Id: I6b9c29d88ce725e640a7ee86c7e1be9761f21b02 Reviewed-on: https://go-review.googlesource.com/c/go/+/513762 Reviewed-by: Ian Lance Taylor TryBot-Result: Gopher Robot Run-TryBot: Dmitri Shuralyov Reviewed-by: Dmitri Shuralyov Auto-Submit: Dmitri Shuralyov --- src/syscall/exec_linux_test.go | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/src/syscall/exec_linux_test.go b/src/syscall/exec_linux_test.go index f4ff7bf81b..e9919b6801 100644 --- a/src/syscall/exec_linux_test.go +++ b/src/syscall/exec_linux_test.go @@ -109,11 +109,17 @@ func TestUnshare(t *testing.T) { t.Fatal(err) } - orig, err := os.ReadFile(path) + b, err := os.ReadFile(path) if err != nil { t.Fatal(err) } - origLines := strings.Split(strings.TrimSpace(string(orig)), "\n") + orig := strings.TrimSpace(string(b)) + if strings.Contains(orig, "lo:") && strings.Count(orig, ":") == 1 { + // This test expects there to be at least 1 more network interface + // in addition to the local network interface, so that it can tell + // that unshare worked. + t.Skip("not enough network interfaces to test unshare with") + } cmd := testenv.Command(t, "cat", path) cmd.SysProcAttr = &syscall.SysProcAttr{ @@ -128,15 +134,18 @@ func TestUnshare(t *testing.T) { t.Fatalf("Cmd failed with err %v, output: %s", err, out) } - // Check there is only the local network interface + // Check there is only the local network interface. sout := strings.TrimSpace(string(out)) if !strings.Contains(sout, "lo:") { t.Fatalf("Expected lo network interface to exist, got %s", sout) } + origLines := strings.Split(orig, "\n") lines := strings.Split(sout, "\n") if len(lines) >= len(origLines) { - t.Fatalf("Got %d lines of output, want <%d", len(lines), len(origLines)) + t.Logf("%s before unshare:\n%s", path, orig) + t.Logf("%s after unshare:\n%s", path, sout) + t.Fatalf("Got %d lines of output, want < %d", len(lines), len(origLines)) } } -- 2.50.0