diff --git a/src/borg/testsuite/legacy_helpers_test.py b/src/borg/testsuite/legacy_helpers_test.py
new file mode 100644
index 000000000..c80cef428
--- /dev/null
+++ b/src/borg/testsuite/legacy_helpers_test.py
@@ -0,0 +1,80 @@
+"""Tests for borg.legacy.helpers (borg1_hardlinkable, borg1_hardlink_master, borg1_hardlink_slave)."""
+
+import stat
+
+from ..item import Item
+from ..legacy.helpers import borg1_hardlink_master, borg1_hardlink_slave, borg1_hardlinkable
+
+
+def _item(**kwargs):
+    base = {"path": "dir/file", "mode": stat.S_IFREG | 0o644, "mtime": 0}
+    base.update(kwargs)
+    return Item(internal_dict=base)
+
+
+# ── borg1_hardlinkable ────────────────────────────────────────────────────────
+
+
+def test_hardlinkable_regular_file():
+    assert borg1_hardlinkable(stat.S_IFREG | 0o644)
+
+
+def test_hardlinkable_block_device():
+    assert borg1_hardlinkable(stat.S_IFBLK | 0o660)
+
+
+def test_hardlinkable_char_device():
+    assert borg1_hardlinkable(stat.S_IFCHR | 0o660)
+
+
+def test_hardlinkable_fifo():
+    assert borg1_hardlinkable(stat.S_IFIFO | 0o644)
+
+
+def test_hardlinkable_symlink_is_false():
+    assert not borg1_hardlinkable(stat.S_IFLNK | 0o777)
+
+
+def test_hardlinkable_directory_is_false():
+    assert not borg1_hardlinkable(stat.S_IFDIR | 0o755)
+
+
+def test_hardlinkable_socket_is_false():
+    assert not borg1_hardlinkable(stat.S_IFSOCK | 0o600)
+
+
+# ── borg1_hardlink_master ─────────────────────────────────────────────────────
+
+
+def test_hardlink_master_true_when_all_conditions_met():
+    item = _item(hardlink_master=True)
+    assert borg1_hardlink_master(item)
+
+
+def test_hardlink_master_false_when_flag_missing():
+    item = _item()
+    assert not borg1_hardlink_master(item)
+
+
+def test_hardlink_master_false_when_flag_is_false():
+    item = _item(hardlink_master=False)
+    assert not borg1_hardlink_master(item)
+
+
+# ── borg1_hardlink_slave ──────────────────────────────────────────────────────
+
+
+def test_hardlink_slave_true_when_source_and_hardlinkable():
+    item = _item(source="dir/original")
+    assert borg1_hardlink_slave(item)
+
+
+def test_hardlink_slave_true_for_non_regular_hardlinkable_type():
+    # borg1_hardlinkable covers FIFO/block/char as well as regular files
+    item = _item(source="dir/original", mode=stat.S_IFIFO | 0o644)
+    assert borg1_hardlink_slave(item)
+
+
+def test_hardlink_slave_false_when_no_source():
+    item = _item()
+    assert not borg1_hardlink_slave(item)