Add comprehensive test coverage for 8 modules

Increases overall test coverage from 53% to 56% by adding tests for:
- accommodation.py (60% → 100%)
- birthday.py (24% → 100%)
- calendar.py (19% → 100%)
- carnival.py (33% → 100%)
- domains.py (75% → 100%)
- events_yaml.py (50% → 96%)
- fx.py (14% → 21% for tested functions)
- sun.py (55% → 100%)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_fx.py

@@ -0,0 +1,182 @@
+"""Tests for foreign exchange functionality."""
+
+import json
+import os
+import tempfile
+from decimal import Decimal
+from unittest.mock import Mock, patch
+
+import pytest
+
+from agenda.fx import read_cached_rates
+
+
+class TestReadCachedRates:
+    """Test the read_cached_rates function."""
+
+    def test_read_cached_rates_none_filename(self) -> None:
+        """Test with None filename returns empty dict."""
+        result = read_cached_rates(None, ["USD", "EUR"])
+        assert result == {}
+
+    def test_read_cached_rates_valid_file(self) -> None:
+        """Test reading valid cached rates file."""
+        currencies = ["USD", "EUR", "JPY"]
+        data = {
+            "quotes": {
+                "GBPUSD": 1.25,
+                "GBPEUR": 1.15,
+                "GBPJPY": 150.0,
+                "GBPCAD": 1.70  # Not requested
+            }
+        }
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            result = read_cached_rates(filepath, currencies)
+            
+            assert len(result) == 3
+            assert result["USD"] == Decimal("1.25")
+            assert result["EUR"] == Decimal("1.15")
+            assert result["JPY"] == Decimal("150.0")
+            assert "CAD" not in result  # Not requested
+            
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_missing_currencies(self) -> None:
+        """Test with some currencies missing from data."""
+        currencies = ["USD", "EUR", "CHF"]  # CHF not in data
+        data = {
+            "quotes": {
+                "GBPUSD": 1.25,
+                "GBPEUR": 1.15
+                # GBPCHF missing
+            }
+        }
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            result = read_cached_rates(filepath, currencies)
+            
+            assert len(result) == 2
+            assert result["USD"] == Decimal("1.25")
+            assert result["EUR"] == Decimal("1.15")
+            assert "CHF" not in result  # Missing from data
+            
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_empty_currencies_list(self) -> None:
+        """Test with empty currencies list."""
+        data = {
+            "quotes": {
+                "GBPUSD": 1.25,
+                "GBPEUR": 1.15
+            }
+        }
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            result = read_cached_rates(filepath, [])
+            assert result == {}
+            
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_no_quotes_key(self) -> None:
+        """Test with data missing quotes key."""
+        currencies = ["USD", "EUR"]
+        data = {"other_key": "value"}  # No quotes key
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            with pytest.raises(KeyError):
+                read_cached_rates(filepath, currencies)
+                
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_file_not_found(self) -> None:
+        """Test error handling when file doesn't exist."""
+        with pytest.raises(FileNotFoundError):
+            read_cached_rates("/nonexistent/file.json", ["USD"])
+
+    def test_read_cached_rates_invalid_json(self) -> None:
+        """Test error handling with invalid JSON."""
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            f.write("invalid json content")
+            filepath = f.name
+        
+        try:
+            with pytest.raises(json.JSONDecodeError):
+                read_cached_rates(filepath, ["USD"])
+                
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_decimal_precision(self) -> None:
+        """Test that rates are returned as Decimal with proper precision."""
+        currencies = ["USD"]
+        data = {
+            "quotes": {
+                "GBPUSD": 1.234567890123456789  # High precision
+            }
+        }
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            result = read_cached_rates(filepath, currencies)
+            
+            assert isinstance(result["USD"], Decimal)
+            # Should preserve reasonable precision from the JSON  
+            # Python's JSON precision may be limited to float precision
+            expected = Decimal("1.234567890123456789")
+            assert abs(result["USD"] - expected) < Decimal("0.0000000000000001")
+            
+        finally:
+            os.unlink(filepath)
+
+    def test_read_cached_rates_various_currency_codes(self) -> None:
+        """Test with various currency codes."""
+        currencies = ["USD", "EUR", "JPY", "CHF", "CAD", "AUD"]
+        data = {
+            "quotes": {
+                "GBPUSD": 1.25,
+                "GBPEUR": 1.15,
+                "GBPJPY": 150.0,
+                "GBPCHF": 1.12,
+                "GBPCAD": 1.70,
+                "GBPAUD": 1.85
+            }
+        }
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(data, f)
+            filepath = f.name
+        
+        try:
+            result = read_cached_rates(filepath, currencies)
+            
+            assert len(result) == 6
+            for currency in currencies:
+                assert currency in result
+                assert isinstance(result[currency], Decimal)
+                
+        finally:
+            os.unlink(filepath)