test: add validator tests for Settings config fields

Author: Pritom14

tests/test_config.py

@@ -0,0 +1,42 @@
+"""Tests for Settings field validators."""
+
+import pytest
+from pydantic import ValidationError
+
+from token0.config import Settings
+
+
+def test_storage_mode_valid_values():
+    assert Settings(storage_mode="lite").storage_mode == "lite"
+    assert Settings(storage_mode="full").storage_mode == "full"
+
+
+def test_storage_mode_invalid_raises():
+    with pytest.raises(ValidationError):
+        Settings(storage_mode="prod")
+
+
+def test_text_density_threshold_valid():
+    assert Settings(text_density_threshold=0.0).text_density_threshold == 0.0
+    assert Settings(text_density_threshold=1.0).text_density_threshold == 1.0
+    assert Settings(text_density_threshold=0.52).text_density_threshold == 0.52
+
+
+def test_text_density_threshold_out_of_range_raises():
+    with pytest.raises(ValidationError):
+        Settings(text_density_threshold=1.1)
+    with pytest.raises(ValidationError):
+        Settings(text_density_threshold=-0.1)
+
+
+def test_port_valid():
+    assert Settings(port=8000).port == 8000
+    assert Settings(port=1).port == 1
+    assert Settings(port=65535).port == 65535
+
+
+def test_port_out_of_range_raises():
+    with pytest.raises(ValidationError):
+        Settings(port=0)
+    with pytest.raises(ValidationError):
+        Settings(port=65536)