Update README: add testing section, production build, test infrastructure docs

README.md

@@ -12,32 +12,45 @@ This project processes petroleum/fuel station transaction data from CSV files an
 - **Invoice Generation**: Generate HTML invoices from CSV data (file-to-file mode)
 - **Multi-Environment**: Separate databases for development, testing, and production
 - **Sales Reporting**: Query transactions by customer, product, date range
+- **Test-Driven Development**: Comprehensive test suite with 45 tests
 
 ## Project Structure
 
 ```
 rusty-petroleum/
 ├── Cargo.toml              # Rust dependencies
+├── Cargo.lock              # Locked dependency versions
 ├── config.example.toml     # Config template
 ├── migrations/            # SQL schema files
-│   ├── 001_dev.sql
+│   └── 002_schema.sql    # Current schema
-│   ├── 001_test.sql
-│   ├── 001_prod.sql
-│   └── 002_schema.sql
 ├── input/                  # CSV input files
 ├── output/                 # Generated invoices
 ├── src/
-│   ├── main.rs            # CLI entry point
+│   ├── lib.rs            # Library crate (for testing)
-│   ├── config.rs          # Configuration loading
+│   ├── main.rs           # CLI entry point
-│   ├── db/                # Database layer
+│   ├── config.rs         # Configuration loading
+│   ├── db/               # Database layer
+│   │   ├── mod.rs
 │   │   ├── connection.rs
 │   │   ├── models.rs
 │   │   └── repository.rs
-│   ├── commands/          # CLI commands
+│   ├── commands/         # CLI commands
-│   │   ├── db.rs          # db setup/reset
+│   │   ├── mod.rs
-│   │   └── import.rs      # CSV import
+│   │   ├── db.rs         # db setup/reset
+│   │   └── import.rs     # CSV import
 │   └── invoice_generator.rs
-└── templates/             # HTML invoice templates
+├── templates/             # HTML invoice templates
+│   ├── index.html
+│   └── customer.html
+└── tests/                # Integration tests
+    ├── common/           # Test utilities
+    │   ├── mod.rs
+    │   ├── fixtures.rs
+    │   └── test_db.rs
+    ├── config_test.rs   # Config module tests
+    ├── import_test.rs    # CSV parsing tests
+    ├── models_test.rs    # Model tests
+    └── repository_test.rs # Database tests
 ```
 
 ## Database Schema
@@ -45,26 +58,30 @@ rusty-petroleum/
 ### customers
 | Column | Type | Description |
 |--------|------|-------------|
-| id | INT | Primary key |
+| id | INT UNSIGNED | Primary key |
 | customer_number | VARCHAR | Unique customer identifier |
-| card_report_group | TINYINT | Customer classification (1=fleet, 3/4=retail) |
+| card_report_group | TINYINT UNSIGNED | Customer classification (1=fleet, 3/4=retail) |
+| created_at | TIMESTAMP | Record creation time |
+| updated_at | TIMESTAMP | Last update time |
 
 ### cards
 | Column | Type | Description |
 |--------|------|-------------|
-| id | INT | Primary key |
+| id | INT UNSIGNED | Primary key |
 | card_number | VARCHAR | Unique card identifier |
-| customer_id | INT | FK to customers |
+| customer_id | INT UNSIGNED | FK to customers |
+| created_at | TIMESTAMP | Record creation time |
+| updated_at | TIMESTAMP | Last update time |
 
 ### transactions
 | Column | Type | Description |
 |--------|------|-------------|
-| id | BIGINT | Primary key |
+| id | BIGINT UNSIGNED | Primary key |
 | transaction_date | DATETIME | Transaction timestamp |
 | batch_number | VARCHAR | Batch identifier |
-| amount | DECIMAL | Transaction amount |
+| amount | DECIMAL(10,2) | Transaction amount |
-| volume | DECIMAL | Volume in liters |
+| volume | DECIMAL(10,3) | Volume in liters |
-| price | DECIMAL | Price per liter |
+| price | DECIMAL(8,4) | Price per liter |
 | quality_code | INT | Product code |
 | quality_name | VARCHAR | Product name (95 Oktan, Diesel) |
 | card_number | VARCHAR | Card used (including anonymized) |
@@ -73,14 +90,15 @@ rusty-petroleum/
 | pump | VARCHAR | Pump number |
 | receipt | VARCHAR | Receipt number |
 | control_number | VARCHAR | Control/verification number |
-| customer_id | INT | FK to customers (NULL for anonymized) |
+| customer_id | INT UNSIGNED | FK to customers (NULL for anonymized) |
+| created_at | TIMESTAMP | Record creation time |
 
 ## Configuration
 
 Copy the example config and edit with your database credentials:
 
 ```bash
-cp config.example.toml config.dev.toml  # or config.test.toml
+cp config.example.toml config.dev.toml  # or config.test.toml or config.prod.toml
 ```
 
 Edit `config.dev.toml`:
@@ -100,6 +118,12 @@ Config files are loaded in order:
 2. `config.<env>.toml` (environment-specific, gitignored)
 3. `config.example.toml` (fallback, tracked)
 
+### Database Names by Environment
+
+- `rusty_petroleum_dev` - Development
+- `rusty_petroleum_test` - Testing
+- `rusty_petroleum_prod` - Production
+
 ## Commands
 
 ```bash
@@ -130,6 +154,53 @@ cargo run -- db reset --env dev
 cargo run -- generate input/409.csv output/
 ```
 
+## Testing
+
+The project has a comprehensive test suite with 45 tests covering config, CSV parsing, models, and database operations.
+
+```bash
+# Run all tests (lib + integration)
+cargo test
+
+# Run only lib/unit tests (fast, no database needed)
+cargo test --lib
+
+# Run only integration tests (requires test database)
+cargo test --tests
+
+# Run a specific test file
+cargo test --test config_test
+cargo test --test import_test
+cargo test --test repository_test
+
+# Run a specific test
+cargo test customer_insert_returns_id
+
+# Run tests in release mode
+cargo test --release
+```
+
+### Test Database Setup
+
+Repository tests require a test database. Run setup before testing:
+
+```bash
+cargo run -- db setup --env test
+```
+
+## Production Build
+
+Build an optimized binary for production:
+
+```bash
+# Build release binary
+cargo build --release
+
+# Run the binary
+./target/release/invoice-generator db setup --env prod
+./target/release/invoice-generator import data.csv --env prod
+```
+
 ## Current Status
 
 ### Implemented
@@ -139,12 +210,12 @@ cargo run -- generate input/409.csv output/
 - [x] Configuration via TOML files
 - [x] Invoice generation (HTML output)
 - [x] Database setup/reset commands
+- [x] Unit tests (45 tests)
 
 ### TODO
 - [ ] Sales reporting queries (dashboard/API)
 - [ ] Customer invoice retrieval from database
 - [ ] Batch import across multiple CSV files
-- [ ] Unit tests
 - [ ] CI/CD pipeline
 
 ## Technology Stack
@@ -154,6 +225,7 @@ cargo run -- generate input/409.csv output/
 - **ORM**: sqlx (async MySQL)
 - **Templating**: Askama (HTML templates)
 - **Config**: TOML
+- **Testing**: tokio-test, tempfile
 
 ## Getting Started
 
@@ -181,6 +253,12 @@ cargo run -- generate input/409.csv output/
    cargo run -- import input/409.csv --env dev
    ```
 
+5. Run tests
+   ```bash
+   cargo test --lib        # Unit tests (fast)
+   cargo test --tests      # Integration tests (requires DB)
+   ```
+
 ## License
 
 See LICENSE file.