pkg/shell: Test signal handling.

pkg/must/must.go

@@ -53,6 +53,16 @@ func ReadAllAndClose(r io.ReadCloser) []byte {
 	return v
 }
 
+// ReadFile wraps os.ReadFile.
+func ReadFile(fname string) []byte {
+	return OK1(os.ReadFile(fname))
+}
+
+// ReadFileString converts the result of ReadFile to a string.
+func ReadFileString(fname string) string {
+	return string(ReadFile(fname))
+}
+
 // MkdirAll calls os.MkdirAll for each argument.
 func MkdirAll(names ...string) {
 	for _, name := range names {

pkg/prog/prog.go

@@ -70,7 +70,9 @@ func Run(fds [3]*os.File, args []string, p Program) int {
 
 	if log != "" {
 		err = logutil.SetOutputFile(log)
-		if err != nil {
+		if err == nil {
+			defer logutil.SetOutput(io.Discard)
+		} else {
 			fmt.Fprintln(fds[2], err)
 		}
 	}

pkg/shell/shell_unix_test.go

@@ -0,0 +1,28 @@
+package shell
+
+import (
+	"strings"
+	"syscall"
+	"testing"
+
+	"src.elv.sh/pkg/must"
+	. "src.elv.sh/pkg/prog/progtest"
+	"src.elv.sh/pkg/testutil"
+)
+
+func TestSignal_USR1(t *testing.T) {
+	Test(t, &Program{},
+		ThatElvish("-c", "kill -USR1 $pid").WritesStderrContaining("src.elv.sh/pkg/shell"))
+}
+
+func TestSignal_Ignored(t *testing.T) {
+	testutil.InTempDir(t)
+
+	Test(t, &Program{},
+		ThatElvish("-log", "logCHLD", "-c", "kill -CHLD $pid").DoesNothing())
+
+	wantLogCHLD := "signal " + syscall.SIGCHLD.String()
+	if logCHLD := must.ReadFileString("logCHLD"); !strings.Contains(logCHLD, wantLogCHLD) {
+		t.Errorf("want log when getting SIGCHLD to contain %q; got:\n%s", wantLogCHLD, logCHLD)
+	}
+}