Add comprehensive GitHub Copilot instructions for consumer-driven-contract-testing repository

.github/copilot-instructions.md

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+# Consumer Driven Contract Testing Workshop
+
+This repository demonstrates Consumer Driven Contract Testing with Spring Cloud Contract using two Spring Boot microservices: customer-service (provider) and invoice-service (consumer).
+
+**Always reference these instructions first and fallback to search or bash commands only when you encounter unexpected information that does not match the info here.**
+
+## Working Effectively
+
+### Bootstrap, Build, and Test
+- Prerequisites: Java 17+ (OpenJDK 17.0.16 pre-installed)
+- Build system: Maven with wrapper (./mvnw)
+- **NEVER CANCEL builds or tests** - they complete quickly in this project
+
+**Essential Commands (validated to work):**
+```bash
+# Clean compile (first run with downloads): ~30 seconds. NEVER CANCEL. Set timeout to 60+ minutes for safety.
+./mvnw clean compile
+
+# Build with working tests: ~6 seconds. NEVER CANCEL. Set timeout to 30+ minutes.
+./mvnw package -Dtest='!CustomerServiceTest#testGetCustomerByIdWithWireMockCloud'
+
+# Test (excluding problematic external dependency): ~6 seconds. NEVER CANCEL. Set timeout to 30+ minutes.
+./mvnw test -Dtest='!CustomerServiceTest#testGetCustomerByIdWithWireMockCloud'
+
+# Build individual services:
+./mvnw -pl customer-service clean verify    # ~8 seconds
+./mvnw -pl invoice-service clean verify     # Fails due to external network dependency
+
+# Install stubs for contract testing: ~4 seconds
+./mvnw -pl customer-service clean install
+```
+
+### Run the Services
+**Start customer-service (provider) on port 9090:**
+```bash
+./mvnw -pl customer-service spring-boot:run
+# Startup time: ~1.5 seconds
+# Access Swagger UI: http://localhost:9090/swagger-ui/index.html
+# Test endpoint: curl http://localhost:9090/customers/cust123
+```
+
+**Start invoice-service (consumer) on port 8080:**
+```bash
+./mvnw -pl invoice-service spring-boot:run  
+# Startup time: ~1.5 seconds
+# Access Swagger UI: http://localhost:8080/swagger-ui/index.html
+```
+
+**Run as JAR files:**
+```bash
+java -jar customer-service/target/customer-service-0.0.1-SNAPSHOT.jar
+java -jar invoice-service/target/invoice-service-0.0.1-SNAPSHOT.jar
+```
+
+## Validation
+
+### Manual Testing Scenarios
+**ALWAYS run through these scenarios after making changes:**
+
+1. **Service Integration Test:**
+   - Start both services
+   - Create an invoice via POST to http://localhost:8080/invoices:
+     ```json
+     {
+       "customerId": "cust123",
+       "invoiceAmountInCents": 2000, 
+       "invoiceDate": "2024-01-01",
+       "description": "invoice for cust123"
+     }
+     ```
+   - Verify response includes customer data from provider service
+   - Note: `postalCode` may be null (known issue addressed by contract testing)
+
+2. **Contract Testing Workflow:**
+   - Install provider stubs: `./mvnw -pl customer-service clean install`
+   - Verify contract tests run (some are @Disabled for tutorial purposes)
+
+### Known Issues and Workarounds
+- **Test failure**: `CustomerServiceTest#testGetCustomerByIdWithWireMockCloud` fails due to external network dependency
+  - **Workaround**: Always exclude this test: `-Dtest='!CustomerServiceTest#testGetCustomerByIdWithWireMockCloud'`
+- **Contract plugin**: Spring Cloud Contract stub runner not configured in invoice-service
+  - **Workaround**: Use customer-service for contract generation and verification
+
+## Common Tasks
+
+### Project Structure
+```
+.
+├── README.md                    # Workshop tutorial instructions
+├── pom.xml                     # Parent Maven configuration
+├── customer-service/           # Provider service (port 9090)
+│   ├── pom.xml
+│   └── src/
+└── invoice-service/            # Consumer service (port 8080)
+    ├── pom.xml
+    └── src/
+```
+
+### Key Dependencies
+- Spring Boot 3.2.5
+- Spring Cloud Contract 4.1.2
+- Java 17
+- Maven 3.9.6
+
+### Build Output Locations
+- Compiled JARs: `{service}/target/{service}-0.0.1-SNAPSHOT.jar`
+- Contract stubs: `customer-service/target/stubs`
+- Test reports: `{service}/target/surefire-reports`
+
+## Development Workflow
+
+### Making Changes
+1. **Always build first**: `./mvnw clean compile` (timeout: 60+ minutes)
+2. **Test your changes**: `./mvnw test -Dtest='!CustomerServiceTest#testGetCustomerByIdWithWireMockCloud'` (timeout: 30+ minutes)
+3. **Manual validation**: Run both services and test integration
+4. **No linting required**: Project has no additional linting beyond Maven compile
+
+### Contract Testing Development
+- Contract definitions: `src/test/resources/contracts/*.groovy`
+- Customer service generates and verifies contracts
+- Invoice service consumes generated stubs
+- Base test class: `customer-service/src/test/java/.../BaseTestClass.java` (@Disabled for tutorial)
+
+### Troubleshooting
+- **Build fails**: Check Java version (requires 17+)
+- **Network test fails**: Use test exclusion parameter as documented above
+- **Port conflicts**: Services run on 8080 and 9090 - ensure ports are available
+- **Contract issues**: Refer to README.md tutorial steps for Spring Cloud Contract setup
+
+### Repository Context
+This is a **workshop/tutorial repository** for learning Consumer Driven Contract Testing. It contains intentionally incomplete contract configurations that are completed through the tutorial exercises in README.md.