container: remove global msg

This frees all container instances of side effects.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/path_test.go

@@ -0,0 +1,43 @@
+package internal
+
+import (
+	"reflect"
+	"testing"
+
+	"hakurei.app/container"
+)
+
+func TestMustCheckPath(t *testing.T) {
+	testCases := []struct {
+		name      string
+		pathname  string
+		wantFatal string
+	}{
+		{"poison", compPoison, "invalid test path, this program is compiled incorrectly"},
+		{"zero", "", "invalid test path, this program is compiled incorrectly"},
+		{"not absolute", "\x00", `path "\x00" is not absolute`},
+		{"success", "/proc/nonexistent", ""},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			fatal := func(v ...any) { t.Fatal(append([]any{"invalid call to fatal:"}, v...)...) }
+			if tc.wantFatal != "" {
+				fatal = func(v ...any) {
+					if len(v) != 1 {
+						t.Errorf("mustCheckPath: fatal %#v", v)
+					} else if gotFatal, ok := v[0].(string); !ok {
+						t.Errorf("mustCheckPath: fatal = %#v", v[0])
+					} else if gotFatal != tc.wantFatal {
+						t.Errorf("mustCheckPath: fatal = %q, want %q", gotFatal, tc.wantFatal)
+					}
+
+					// do not simulate exit
+				}
+			}
+
+			if got := mustCheckPath(fatal, "test", tc.pathname); got != nil && !reflect.DeepEqual(got, container.MustAbs(tc.pathname)) {
+				t.Errorf("mustCheckPath: %q", got)
+			}
+		})
+	}
+}