"""
Tests for engine.app module.
"""

from engine.app import _normalize_preview_rows


class TestNormalizePreviewRows:
    """Tests for _normalize_preview_rows function."""

    def test_empty_rows(self):
        """Empty input returns empty list."""
        result = _normalize_preview_rows([])
        assert result == [""]

    def test_strips_left_padding(self):
        """Left padding is stripped."""
        result = _normalize_preview_rows(["  content", "  more"])
        assert all(not r.startswith(" ") for r in result)

    def test_preserves_content(self):
        """Content is preserved."""
        result = _normalize_preview_rows(["  hello world  "])
        assert "hello world" in result[0]

    def test_handles_all_empty_rows(self):
        """All empty rows returns single empty string."""
        result = _normalize_preview_rows(["", "   ", ""])
        assert result == [""]


class TestAppConstants:
    """Tests for app module constants."""

    def test_title_defined(self):
        """TITLE is defined."""
        from engine.app import TITLE

        assert len(TITLE) > 0

    def test_title_lines_are_strings(self):
        """TITLE contains string lines."""
        from engine.app import TITLE

        assert all(isinstance(line, str) for line in TITLE)


class TestAppImports:
    """Tests for app module imports."""

    def test_app_imports_without_error(self):
        """Module imports without error."""
        from engine import app

        assert app is not None