"""Tests for template entity validation."""

import pytest
from dataclasses import dataclass


# ---------------------------------------------------------------------------
# Stub domain object -- replace with real import later
# ---------------------------------------------------------------------------
@dataclass
class Template:
    name: str
    description: str = ""
    chart_spec_ids: list[str] | None = None

    def validate(self) -> list[str]:
        """Return a list of validation error messages (empty == valid)."""
        errors: list[str] = []
        if not self.name or not self.name.strip():
            errors.append("Template name must not be empty.")
        if len(self.name) > 200:
            errors.append("Template name must not exceed 200 characters.")
        return errors


# ---------------------------------------------------------------------------
# Tests
# ---------------------------------------------------------------------------
class TestTemplateValidation:
    """Ensure template entity enforces basic invariants."""

    def test_empty_name_fails_validation(self):
        t = Template(name="")
        errors = t.validate()
        assert any("empty" in e.lower() for e in errors)

    def test_whitespace_only_name_fails_validation(self):
        t = Template(name="   ")
        errors = t.validate()
        assert any("empty" in e.lower() for e in errors)

    def test_valid_name_passes(self):
        t = Template(name="Q1 Sales Report")
        assert t.validate() == []

    def test_excessively_long_name_fails(self):
        t = Template(name="x" * 201)
        errors = t.validate()
        assert any("200" in e for e in errors)

    def test_name_at_boundary_passes(self):
        t = Template(name="x" * 200)
        assert t.validate() == []