testsuite: improve haiku compatibility

haiku does not have os.mknod.
and it looks like it does not have hardlinks either.

src/borg/testsuite/__init__.py

@@ -26,6 +26,8 @@ from ..platformflags import is_win32
 # Does this version of llfuse support ns precision?
 have_fuse_mtime_ns = hasattr(llfuse.EntryAttributes, "st_mtime_ns") if llfuse else False
 
+has_mknod = hasattr(os, "mknod")
+
 has_lchflags = hasattr(os, "lchflags") or sys.platform.startswith("linux")
 try:
     with tempfile.NamedTemporaryFile() as file:

src/borg/testsuite/archiver/__init__.py

@@ -26,7 +26,7 @@ from ...manifest import Manifest
 from ...platform import get_flags
 from ...remote import RemoteRepository
 from ...repository import Repository
-from .. import has_lchflags, is_utime_fully_supported, have_fuse_mtime_ns, st_mtime_ns_round, no_selinux
+from .. import has_lchflags, has_mknod, is_utime_fully_supported, have_fuse_mtime_ns, st_mtime_ns_round, no_selinux
 from .. import changedir
 from .. import are_symlinks_supported, are_hardlinks_supported, are_fifos_supported
 from ..platform.platform_test import is_win32
@@ -232,10 +232,11 @@ def create_test_files(input_path, create_hardlinks=True):
         have_root = False
     else:
         try:
-            # Block device
-            os.mknod("input/bdev", 0o600 | stat.S_IFBLK, os.makedev(10, 20))
-            # Char device
-            os.mknod("input/cdev", 0o600 | stat.S_IFCHR, os.makedev(30, 40))
+            if has_mknod:
+                # Block device
+                os.mknod("input/bdev", 0o600 | stat.S_IFBLK, os.makedev(10, 20))
+                # Char device
+                os.mknod("input/cdev", 0o600 | stat.S_IFCHR, os.makedev(30, 40))
             # File owner
             os.chown("input/file1", 100, 200)  # raises OSError invalid argument on cygwin
             # File mode

src/borg/testsuite/archiver/create_cmd_test.py

@@ -17,7 +17,7 @@ from ...manifest import Manifest
 from ...platform import is_win32, is_darwin
 from ...repository import Repository
 from ...helpers import CommandError, BackupPermissionError
-from .. import has_lchflags
+from .. import has_lchflags, has_mknod
 from .. import changedir
 from .. import (
     are_symlinks_supported,
@@ -84,7 +84,7 @@ def test_basic_functionality(archivers, request):
         expected.append("input/link1")
     if are_hardlinks_supported():
         expected.append("input/hardlink")
-    if not have_root:
+    if not have_root or not has_mknod:
         # We could not create these device files without (fake)root.
         expected.remove("input/bdev")
         expected.remove("input/cdev")

src/borg/testsuite/archiver/extract_cmd_test.py

@@ -703,6 +703,7 @@ def test_do_not_fail_when_percent_is_in_file_name(archivers, request):
             cmd(archiver, "extract", "test", exit_code=EXIT_WARNING)
 
 
+@pytest.mark.skipif(not are_hardlinks_supported(), reason="hardlinks not supported")
 def test_extract_continue(archivers, request):
     archiver = request.getfixturevalue(archivers)
     CONTENTS1, CONTENTS2, CONTENTS3 = b"contents1" * 100, b"contents2" * 200, b"contents3" * 300