diff --git a/tests/test_platform.py b/tests/test_platform.py
new file mode 100644
index 0000000..583bed5
--- /dev/null
+++ b/tests/test_platform.py
@@ -0,0 +1,43 @@
+"""Тесты платформенно-зависимой диагностики (platform.py)."""
+
+from __future__ import annotations
+
+from selectel_ml_tui import platform as pl
+
+
+def test_platform_info_fields(monkeypatch) -> None:
+    monkeypatch.setenv("TERM", "xterm-256color")
+    monkeypatch.setenv("LANG", "ru_RU.UTF-8")
+    info = pl.get_platform_info()
+    assert info.system in ("Linux", "Darwin", "Windows")
+    assert info.term == "xterm-256color"
+    assert info.lang == "ru_RU.UTF-8"
+    assert info.utf8 is True
+    assert info.python_version
+
+
+def test_check_environment_ok(monkeypatch) -> None:
+    monkeypatch.setenv("TERM", "tmux-256color")
+    monkeypatch.setenv("LANG", "en_US.UTF-8")
+    results = {c.name: c for c in pl.check_environment()}
+    assert all(r.ok for r in results.values())
+    assert results["python"].ok
+
+
+def test_check_environment_warns_without_term_and_lang(monkeypatch) -> None:
+    monkeypatch.delenv("TERM", raising=False)
+    monkeypatch.delenv("LANG", raising=False)
+    results = {c.name: c for c in pl.check_environment()}
+    assert not results["TERM"].ok
+    assert not results["LANG"].ok
+
+
+def test_check_environment_warns_wrong_term(monkeypatch) -> None:
+    monkeypatch.setenv("TERM", "dumb")
+    monkeypatch.setenv("LANG", "C")
+    results = {c.name: c for c in pl.check_environment()}
+    assert not results["TERM"].ok
+
+
+def test_min_python_version() -> None:
+    assert pl.MIN_PYTHON == (3, 10)