all: use ^TestName$ regular pattern for invoking a single test

Use ^ and $ in the -run flag regular expression value when the intention
is to invoke a single named test. This removes the reliance on there not
being another similarly named test to achieve the intended result.

In particular, package syscall has tests named TestUnshareMountNameSpace
and TestUnshareMountNameSpaceChroot that both trigger themselves setting
GO_WANT_HELPER_PROCESS=1 to run alternate code in a helper process. As a
consequence of overlap in their test names, the former was inadvertently
triggering one too many helpers.

Spotted while reviewing CL 525196. Apply the same change in other places
to make it easier for code readers to see that said tests aren't running
extraneous tests. The unlikely cases of -run=TestSomething intentionally
being used to run all tests that have the TestSomething substring in the
name can be better written as -run=^.*TestSomething.*$ or with a comment
so it is clear it wasn't an oversight.

Change-Id: Iba208aba3998acdbf8c6708e5d23ab88938bfc1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/524948
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Kirill Kolyshkin <kolyshkin@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

6 files changed, 12 insertions, 12 deletions

diff --git a/src/os/os_test.go b/src/os/os_test.go
index c5776a9f29..25837dce9e 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -2609,7 +2609,7 @@ func TestGetppid(t *testing.T) {
 	testenv.MustHaveExec(t)
 	t.Parallel()
 
-	cmd := testenv.Command(t, Args[0], "-test.run=TestGetppid")
+	cmd := testenv.Command(t, Args[0], "-test.run=^TestGetppid$")
 	cmd.Env = append(Environ(), "GO_WANT_HELPER_PROCESS=1")
 
 	// verify that Getppid() from the forked process reports our process id
diff --git a/src/os/os_windows_test.go b/src/os/os_windows_test.go
index bfbe7ec815..90c1eabd96 100644
--- a/src/os/os_windows_test.go
+++ b/src/os/os_windows_test.go
@@ -1228,7 +1228,7 @@ func TestRootDirAsTemp(t *testing.T) {
 		t.Skip(err)
 	}
 
-	cmd := testenv.Command(t, exe, "-test.run=TestRootDirAsTemp")
+	cmd := testenv.Command(t, exe, "-test.run=^TestRootDirAsTemp$")
 	cmd.Env = cmd.Environ()
 	cmd.Env = append(cmd.Env, "GO_WANT_HELPER_PROCESS=1")
 	cmd.Env = append(cmd.Env, "TMP="+newtmp)
diff --git a/src/os/pipe_test.go b/src/os/pipe_test.go
index 6f01d30e24..a9e0c8bc8a 100644
--- a/src/os/pipe_test.go
+++ b/src/os/pipe_test.go
@@ -263,7 +263,7 @@ func TestReadNonblockingFd(t *testing.T) {
 	}
 	defer r.Close()
 	defer w.Close()
-	cmd := testenv.Command(t, os.Args[0], "-test.run="+t.Name())
+	cmd := testenv.Command(t, os.Args[0], "-test.run=^"+t.Name()+"$")
 	cmd.Env = append(cmd.Environ(), "GO_WANT_READ_NONBLOCKING_FD=1")
 	cmd.Stdin = r
 	output, err := cmd.CombinedOutput()
diff --git a/src/os/removeall_test.go b/src/os/removeall_test.go
index 2f7938bb5c..c0b2dd6505 100644
--- a/src/os/removeall_test.go
+++ b/src/os/removeall_test.go
@@ -489,7 +489,7 @@ func TestRemoveAllNoFcntl(t *testing.T) {
 		}
 	}
 
-	cmd := testenv.Command(t, "/bin/strace", "-f", "-e", "fcntl", me, "-test.run=TestRemoveAllNoFcntl")
+	cmd := testenv.Command(t, "/bin/strace", "-f", "-e", "fcntl", me, "-test.run=^TestRemoveAllNoFcntl$")
 	cmd = testenv.CleanCmdEnv(cmd)
 	cmd.Env = append(cmd.Env, env+"="+subdir)
 	out, err := cmd.CombinedOutput()
diff --git a/src/os/signal/signal_cgo_test.go b/src/os/signal/signal_cgo_test.go
index 5e85f45e70..9e9a9fe526 100644
--- a/src/os/signal/signal_cgo_test.go
+++ b/src/os/signal/signal_cgo_test.go
@@ -130,7 +130,7 @@ func TestTerminalSignal(t *testing.T) {
 
 	var (
 		ctx     = context.Background()
-		cmdArgs = []string{"-test.run=TestTerminalSignal"}
+		cmdArgs = []string{"-test.run=^TestTerminalSignal$"}
 	)
 	if deadline, ok := t.Deadline(); ok {
 		d := time.Until(deadline)
@@ -250,7 +250,7 @@ func runSessionLeader(t *testing.T, pause time.Duration) {
 
 	var (
 		ctx     = context.Background()
-		cmdArgs = []string{"-test.run=TestTerminalSignal"}
+		cmdArgs = []string{"-test.run=^TestTerminalSignal$"}
 	)
 	if deadline, ok := t.Deadline(); ok {
 		d := time.Until(deadline)
diff --git a/src/os/signal/signal_test.go b/src/os/signal/signal_test.go
index e5af885511..e7575eb70e 100644
--- a/src/os/signal/signal_test.go
+++ b/src/os/signal/signal_test.go
@@ -304,7 +304,7 @@ func TestDetectNohup(t *testing.T) {
 		// We have no intention of reading from c.
 		c := make(chan os.Signal, 1)
 		Notify(c, syscall.SIGHUP)
-		if out, err := testenv.Command(t, os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput(); err == nil {
+		if out, err := testenv.Command(t, os.Args[0], "-test.run=^TestDetectNohup$", "-check_sighup_ignored").CombinedOutput(); err == nil {
 			t.Errorf("ran test with -check_sighup_ignored and it succeeded: expected failure.\nOutput:\n%s", out)
 		}
 		Stop(c)
@@ -315,7 +315,7 @@ func TestDetectNohup(t *testing.T) {
 		}
 		Ignore(syscall.SIGHUP)
 		os.Remove("nohup.out")
-		out, err := testenv.Command(t, "/usr/bin/nohup", os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput()
+		out, err := testenv.Command(t, "/usr/bin/nohup", os.Args[0], "-test.run=^TestDetectNohup$", "-check_sighup_ignored").CombinedOutput()
 
 		data, _ := os.ReadFile("nohup.out")
 		os.Remove("nohup.out")
@@ -440,7 +440,7 @@ func TestNohup(t *testing.T) {
 
 			args := []string{
 				"-test.v",
-				"-test.run=TestStop",
+				"-test.run=^TestStop$",
 				"-send_uncaught_sighup=" + strconv.Itoa(i),
 				"-die_from_sighup",
 			}
@@ -491,7 +491,7 @@ func TestNohup(t *testing.T) {
 			args := []string{
 				os.Args[0],
 				"-test.v",
-				"-test.run=TestStop",
+				"-test.run=^TestStop$",
 				"-send_uncaught_sighup=" + strconv.Itoa(i),
 			}
 			if subTimeout != 0 {
@@ -546,7 +546,7 @@ func TestAtomicStop(t *testing.T) {
 		if deadline, ok := t.Deadline(); ok {
 			timeout = time.Until(deadline).String()
 		}
-		cmd := testenv.Command(t, os.Args[0], "-test.run=TestAtomicStop", "-test.timeout="+timeout)
+		cmd := testenv.Command(t, os.Args[0], "-test.run=^TestAtomicStop$", "-test.timeout="+timeout)
 		cmd.Env = append(os.Environ(), "GO_TEST_ATOMIC_STOP=1")
 		out, err := cmd.CombinedOutput()
 		if err == nil {
@@ -742,7 +742,7 @@ func TestNotifyContextNotifications(t *testing.T) {
 
 			args := []string{
 				"-test.v",
-				"-test.run=TestNotifyContextNotifications$",
+				"-test.run=^TestNotifyContextNotifications$",
 				"-check_notify_ctx",
 				fmt.Sprintf("-ctx_notify_times=%d", tc.n),
 			}