feat: implement cost report template generator with Claude session tracking (issue #119)

Comprehensive cost tracking system implementation including:

- Cost report generator with multiple formats (summary, detailed, audit)
- Full CLI integration with cost management commands
- Claude session cost tracking and estimation
- Professional markdown reports with frontmatter/contentmatter
- Automatic cost note generation for issue implementations
- Complete test coverage (33 test cases)
- Database integration with finance schema initialization

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

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

tests/test_cost_report_generator.py

@@ -0,0 +1,357 @@
+"""
+Tests for MarkiTect cost report template generator.
+
+This module tests the complete cost report generation functionality including:
+- Report generation in different formats (summary, detailed, audit)
+- Markdown output with frontmatter and contentmatter
+- CLI integration and command functionality
+- Template structure validation
+"""
+
+import pytest
+import tempfile
+import os
+import json
+from datetime import date, datetime
+from decimal import Decimal
+
+from markitect.finance.cost_manager import CostItemManager, CostItem
+from markitect.finance.report_generator import CostReportGenerator, ReportConfig
+from markitect.finance.models import FinanceModels
+
+
+class TestCostReportGenerator:
+    """Test suite for cost report generation system."""
+
+    @pytest.fixture
+    def temp_db(self):
+        """Create temporary database for testing."""
+        fd, path = tempfile.mkstemp(suffix='.db')
+        os.close(fd)
+        yield path
+        os.unlink(path)
+
+    @pytest.fixture
+    def setup_test_data(self, temp_db):
+        """Setup test database with sample cost data."""
+        finance_models = FinanceModels(temp_db)
+        finance_models.initialize_finance_schema()
+
+        cost_manager = CostItemManager(temp_db)
+
+        # Get categories
+        infra_cat = cost_manager.get_category_by_name('Infrastructure')
+        software_cat = cost_manager.get_category_by_name('Software')
+
+        # Create sample cost items
+        cost_items = [
+            CostItem(
+                category_id=infra_cat['id'],
+                name='Hosteurope Server',
+                description='Monthly server hosting',
+                cost_type='monthly',
+                amount_eur=Decimal('10.00'),
+                starting_from_date=date(2025, 1, 1)
+            ),
+            CostItem(
+                category_id=software_cat['id'],
+                name='Bubble.io Plan',
+                description='No-code platform subscription',
+                cost_type='monthly',
+                amount_eur=Decimal('32.00'),
+                starting_from_date=date(2025, 1, 1)
+            ),
+            CostItem(
+                category_id=infra_cat['id'],
+                name='SSL Certificate',
+                description='Annual SSL certificate',
+                cost_type='one_time',
+                amount_eur=Decimal('45.00'),
+                starting_from_date=date(2025, 1, 15)
+            )
+        ]
+
+        for item in cost_items:
+            cost_manager.create_cost_item(item)
+
+        return temp_db
+
+    @pytest.fixture
+    def report_generator(self, setup_test_data):
+        """Create report generator with test data."""
+        return CostReportGenerator(setup_test_data)
+
+    def test_report_config_creation(self):
+        """Test ReportConfig dataclass creation."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31),
+            currency="EUR"
+        )
+
+        assert config.format == "summary"
+        assert config.period_start == date(2025, 1, 1)
+        assert config.period_end == date(2025, 1, 31)
+        assert config.currency == "EUR"
+        assert config.include_inactive is False
+        assert config.output_path is None
+
+    def test_generate_summary_report(self, report_generator):
+        """Test generation of summary cost report."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Check that it's valid markdown with frontmatter
+        assert report.startswith("---")
+        assert "Cost Summary Report - January 2025" in report
+        assert "total_costs: 87.0" in report
+        assert "report_type: \"cost_summary\"" in report
+
+        # Check contentmatter is present
+        assert "contentmatter:" in report
+        assert "cost_data" in report
+
+        # Verify total costs are correct (10 + 32 + 45 = 87)
+        assert "€87.00" in report
+
+    def test_generate_detailed_report(self, report_generator):
+        """Test generation of detailed cost report."""
+        config = ReportConfig(
+            format="detailed",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Check report structure
+        assert "Detailed Cost Report - January 2025" in report
+        assert "Executive Summary" in report
+        assert "report_type: \"cost_detailed\"" in report
+
+        # Check category sections are present
+        assert "Infrastructure" in report
+        assert "Software" in report
+
+        # Check individual items are listed
+        assert "Hosteurope Server" in report
+        assert "Bubble.io Plan" in report
+        assert "SSL Certificate" in report
+
+        # Check table format
+        assert "| Name | Type | Amount | Status | Start Date |" in report
+
+    def test_generate_audit_report(self, report_generator):
+        """Test generation of audit trail report."""
+        config = ReportConfig(
+            format="audit",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Check report structure
+        assert "Cost Audit Report - January 2025" in report
+        assert "Audit Summary" in report
+        assert "report_type: \"cost_audit\"" in report
+        assert "audit_trail: True" in report
+
+        # Check audit sections
+        assert "Cost Verification" in report
+        assert "Active Cost Items" in report
+        assert "Transaction History" in report
+        assert "Audit Trail" in report
+
+        # Check contentmatter includes audit data
+        assert "audit_data" in report
+
+    def test_generate_period_report_convenience_method(self, report_generator):
+        """Test convenience method for generating monthly reports."""
+        report = report_generator.generate_period_report(2025, 1, "summary")
+
+        assert "Cost Summary Report - January 2025" in report
+        assert "2025-01-01" in report
+        assert "2025-01-31" in report
+
+    def test_invalid_report_format_raises_error(self, report_generator):
+        """Test that invalid report format raises ValueError."""
+        config = ReportConfig(
+            format="invalid",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        with pytest.raises(ValueError, match="Unknown report format"):
+            report_generator.generate_report(config)
+
+    def test_frontmatter_structure(self, report_generator):
+        """Test frontmatter structure in generated reports."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Extract frontmatter (between first two ---)
+        lines = report.split('\n')
+        frontmatter_lines = []
+        in_frontmatter = False
+
+        for line in lines:
+            if line.strip() == "---":
+                if not in_frontmatter:
+                    in_frontmatter = True
+                    continue
+                else:
+                    break
+            if in_frontmatter:
+                frontmatter_lines.append(line)
+
+        frontmatter_text = '\n'.join(frontmatter_lines)
+
+        # Check required frontmatter fields
+        assert 'report_type:' in frontmatter_text
+        assert 'period_start:' in frontmatter_text
+        assert 'period_end:' in frontmatter_text
+        assert 'total_costs:' in frontmatter_text
+        assert 'currency:' in frontmatter_text
+        assert 'generated_at:' in frontmatter_text
+
+    def test_contentmatter_structure(self, report_generator):
+        """Test contentmatter structure in generated reports."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Extract contentmatter (JSON in HTML comment)
+        assert "<!--" in report
+        assert "contentmatter:" in report
+        assert "-->" in report
+
+        # Find and extract JSON
+        start = report.find("contentmatter:\n") + len("contentmatter:\n")
+        end = report.find("\n-->")
+        json_text = report[start:end].strip()
+
+        # Parse JSON to verify structure
+        contentmatter = json.loads(json_text)
+
+        assert "cost_data" in contentmatter
+        assert "total_monthly" in contentmatter["cost_data"]
+        assert "total_one_time" in contentmatter["cost_data"]
+        assert "categories" in contentmatter["cost_data"]
+        assert "active_items" in contentmatter["cost_data"]
+
+        # Verify totals
+        assert contentmatter["cost_data"]["total_monthly"] == 42.0
+        assert contentmatter["cost_data"]["total_one_time"] == 45.0
+
+    def test_save_report_to_file(self, report_generator, temp_db):
+        """Test saving report to file."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Save to temporary file
+        with tempfile.NamedTemporaryFile(mode='w', delete=False, suffix='.md') as f:
+            output_path = f.name
+
+        try:
+            report_generator.save_report(report, output_path)
+
+            # Verify file was created and contains expected content
+            with open(output_path, 'r', encoding='utf-8') as f:
+                saved_content = f.read()
+
+            assert saved_content == report
+            assert "Cost Summary Report" in saved_content
+
+        finally:
+            os.unlink(output_path)
+
+    def test_empty_database_report(self, temp_db):
+        """Test report generation with empty database."""
+        # Initialize empty database
+        finance_models = FinanceModels(temp_db)
+        finance_models.initialize_finance_schema()
+
+        report_generator = CostReportGenerator(temp_db)
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31)
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Should still generate valid report with zero costs
+        assert "total_costs: 0.0" in report
+        assert "€0.00" in report
+
+    def test_different_currency(self, report_generator):
+        """Test report generation with different currency."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31),
+            currency="USD"
+        )
+
+        report = report_generator.generate_report(config)
+
+        assert 'currency: "USD"' in report
+        # Note: amounts are still in EUR from database, currency is just metadata
+
+    def test_report_with_inactive_items(self, setup_test_data):
+        """Test report behavior with inactive cost items."""
+        cost_manager = CostItemManager(setup_test_data)
+
+        # Deactivate one item
+        items = cost_manager.list_cost_items()
+        if items:
+            cost_manager.deactivate_cost_item(items[0]['id'], date(2025, 1, 15))
+
+        report_generator = CostReportGenerator(setup_test_data)
+        config = ReportConfig(
+            format="detailed",
+            period_start=date(2025, 1, 1),
+            period_end=date(2025, 1, 31),
+            include_inactive=False
+        )
+
+        report = report_generator.generate_report(config)
+
+        # Should still generate valid report, potentially with fewer active items
+        assert "Detailed Cost Report" in report
+        assert "contentmatter:" in report
+
+    def test_cross_month_period(self, report_generator):
+        """Test report generation across multiple months."""
+        config = ReportConfig(
+            format="summary",
+            period_start=date(2025, 1, 15),
+            period_end=date(2025, 2, 15)
+        )
+
+        report = report_generator.generate_report(config)
+
+        assert "2025-01-15" in report
+        assert "2025-02-15" in report
+        # Should include items active during this period