diff --git a/tests/test_hostname.py b/tests/test_hostname.py
new file mode 100644
index 0000000..a0f3573
--- /dev/null
+++ b/tests/test_hostname.py
@@ -0,0 +1,111 @@
+import os
+import sys
+import importlib
+import xml.etree.ElementTree as ET
+
+
+PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+if PROJECT_ROOT not in sys.path:
+    sys.path.insert(0, PROJECT_ROOT)
+
+
+def import_hostname():
+    module_name = "scripts.hostname"
+    if module_name in sys.modules:
+        del sys.modules[module_name]
+    return importlib.import_module(module_name)
+
+
+def test_generate_random_string_length_and_charset():
+    hostname = import_hostname()
+    s = hostname.generate_random_string(10)
+    assert len(s) == 10
+    assert s.islower()
+    assert s.isalpha()
+
+
+def test_update_config_hostname_updates_xml(tmp_path):
+    hostname = import_hostname()
+
+    xml_path = tmp_path / "config.xml"
+    xml_path.write_text(
+        "<config><hostname>OLD</hostname><other>1</other></config>",
+        encoding="utf-8",
+    )
+
+    old, changed = hostname.update_config_hostname(str(xml_path), "NEWNAME")
+    assert changed is True
+    assert old == "OLD"
+
+    # Vérifie que le fichier a été modifié
+    tree = ET.parse(str(xml_path))
+    root = tree.getroot()
+    assert root.find("hostname").text == "NEWNAME"
+
+
+def test_update_config_hostname_no_hostname_element(tmp_path):
+    hostname = import_hostname()
+
+    xml_path = tmp_path / "config.xml"
+    xml_path.write_text("<config><other>1</other></config>", encoding="utf-8")
+
+    old, changed = hostname.update_config_hostname(str(xml_path), "NEWNAME")
+    assert changed is False
+    assert old is None
+
+
+def test_main_does_nothing_when_hostname_different(monkeypatch):
+    hostname = import_hostname()
+
+    # Hostname différent => pas de changement
+    monkeypatch.setattr(hostname.socket, "gethostname", lambda: "already-set")
+
+    calls = {"apply": 0, "update": 0}
+
+    def fake_update(path, new):
+        calls["update"] += 1
+        return ("OLD", True)
+
+    def fake_apply(new):
+        calls["apply"] += 1
+        return 0
+
+    monkeypatch.setattr(hostname, "update_config_hostname", fake_update)
+    monkeypatch.setattr(hostname, "apply_hostname", fake_apply)
+    monkeypatch.setattr(hostname, "configure_logging", lambda: None)
+
+    hostname.main(expected_hostname="sd-satxx.dtx.io", config_path="/tmp/config.xml")
+
+    assert calls["update"] == 0
+    assert calls["apply"] == 0
+
+
+def test_main_changes_when_expected_hostname(monkeypatch):
+    hostname = import_hostname()
+
+    # Hostname attendu => change
+    monkeypatch.setattr(hostname.socket, "gethostname", lambda: "sd-satxx.dtx.io")
+    monkeypatch.setattr(hostname, "configure_logging", lambda: None)
+
+    # Fige le random
+    monkeypatch.setattr(hostname, "generate_random_string", lambda n: "abcdefghij")
+
+    captured = {"new": None, "config_path": None, "applied": None}
+
+    def fake_update(path, new):
+        captured["config_path"] = path
+        captured["new"] = new
+        return ("OLDHOST", True)
+
+    def fake_apply(new):
+        captured["applied"] = new
+        return 0
+
+    monkeypatch.setattr(hostname, "update_config_hostname", fake_update)
+    monkeypatch.setattr(hostname, "apply_hostname", fake_apply)
+
+    hostname.main(expected_hostname="sd-satxx.dtx.io", config_path="/conf/config.xml")
+
+    assert captured["new"] == "DTX-SDSAT-abcdefghij"
+    assert captured["applied"] == "DTX-SDSAT-abcdefghij"
+    assert captured["config_path"] == "/conf/config.xml"