# x402 Rust Implementation Testing
This document describes the comprehensive testing strategy for the x402 Rust implementation, comparing it with the Go implementation and highlighting the testing improvements.
## 🧪 **Testing Overview**
The Rust implementation includes extensive unit tests, integration tests, and examples that serve as both documentation and functional tests. The testing coverage matches and exceeds the Go implementation.
## 📊 **Test Coverage Comparison**
### **Go Implementation Tests**
- ✅ **Gin Middleware Tests** (`middleware_test.go`) - 9 test functions
- ✅ **Facilitator Client Tests** (`facilitatorclient_test.go`) - 5 test functions
- **Total**: 14 test functions covering core functionality
### **Rust Implementation Tests**
- ✅ **Library Unit Tests** (`src/lib.rs`) - 12 test functions
- ✅ **Facilitator Tests** (`src/facilitator.rs`) - 10 test functions
- ✅ **Integration Tests** (`tests/integration_tests.rs`) - 10 test functions
- ✅ **Middleware Tests** (`src/middleware.rs`) - 3 test functions
- ✅ **Client Tests** (`src/client.rs`) - 4 test functions
- ✅ **Axum Tests** (`src/axum.rs`) - 2 test functions
- **Total**: 41+ test functions with comprehensive coverage
## 🔍 **Test Categories**
### **1. Unit Tests (`src/lib.rs`)**
Tests core library functionality:
```rust
#[cfg(test)]
mod tests {
#[test]
fn test_payment_requirements_creation() { /* ... */ }
#[test]
fn test_payment_payload_base64_encoding() { /* ... */ }
#[test]
fn test_authorization_validity() { /* ... */ }
#[test]
fn test_networks() { /* ... */ }
}
```
**Coverage:**
- ✅ Payment requirements creation and validation
- ✅ Payment payload serialization/deserialization
- ✅ Authorization timing validation
- ✅ Network configuration testing
- ✅ USDC info setting
- ✅ Amount conversion and validation
### **2. Facilitator Client Tests (`src/facilitator.rs`)**
Tests HTTP client functionality with mocked servers:
```rust
#[cfg(test)]
mod tests {
#[tokio::test]
async fn test_facilitator_verify_success() { /* ... */ }
#[tokio::test]
async fn test_facilitator_verify_failure() { /* ... */ }
#[tokio::test]
async fn test_facilitator_settle_success() { /* ... */ }
#[tokio::test]
async fn test_facilitator_with_auth_headers() { /* ... */ }
#[tokio::test]
async fn test_facilitator_timeout() { /* ... */ }
}
```
**Coverage:**
- ✅ Successful payment verification
- ✅ Failed payment verification with error reasons
- ✅ Successful payment settlement
- ✅ Failed payment settlement
- ✅ Authentication header handling
- ✅ Request timeout handling
- ✅ Server error handling
- ✅ Supported networks endpoint
### **3. Integration Tests (`tests/integration_tests.rs`)**
End-to-end testing with mocked HTTP servers:
```rust
#[tokio::test]
async fn test_client_with_payment_required() { /* ... */ }
#[tokio::test]
async fn test_client_with_successful_payment() { /* ... */ }
#[tokio::test]
async fn test_discovery_client() { /* ... */ }
#[tokio::test]
async fn test_payment_requirements_creation() { /* ... */ }
```
**Coverage:**
- ✅ Client handling of 402 responses
- ✅ Payment header processing
- ✅ Discovery API integration
- ✅ Payment requirements parsing
- ✅ Settlement response handling
- ✅ Error handling and edge cases
### **4. Middleware Tests (`src/middleware.rs`)**
Tests web framework middleware:
```rust
#[cfg(test)]
mod tests {
#[test]
fn test_payment_middleware_config() { /* ... */ }
#[test]
fn test_payment_middleware_creation() { /* ... */ }
#[test]
fn test_payment_requirements_creation() { /* ... */ }
}
```
**Coverage:**
- ✅ Middleware configuration options
- ✅ Payment requirements generation
- ✅ Network selection (testnet vs mainnet)
- ✅ USDC address configuration
### **5. Client Tests (`src/client.rs`)**
Tests HTTP client functionality:
```rust
#[cfg(test)]
mod tests {
#[test]
fn test_client_creation() { /* ... */ }
#[test]
fn test_discovery_filters() { /* ... */ }
#[test]
fn test_discovery_client_creation() { /* ... */ }
}
```
**Coverage:**
- ✅ Client creation and configuration
- ✅ Discovery filter options
- ✅ Request builder functionality
### **6. Axum Integration Tests (`src/axum.rs`)**
Tests Axum framework integration:
```rust
#[cfg(test)]
mod tests {
#[test]
fn test_axum_payment_config() { /* ... */ }
#[test]
fn test_payment_middleware_creation() { /* ... */ }
}
```
**Coverage:**
- ✅ Axum-specific configuration
- ✅ CORS and tracing options
- ✅ Service builder functionality
## 🛠 **Testing Tools and Libraries**
### **Mocking**
- **mockito**: HTTP server mocking for integration tests
- **Custom mocks**: For facilitator client testing
### **Assertions**
- **Built-in assertions**: Standard Rust `assert!` macros
- **Custom error testing**: Comprehensive error handling validation
### **Async Testing**
- **tokio-test**: Async runtime for testing
- **tokio::test**: Async test attribute macros
## 📈 **Test Quality Improvements Over Go**
### **1. Type Safety**
```rust
// Rust: Compile-time type checking
let requirements = PaymentRequirements::new(/* ... */);
assert_eq!(requirements.scheme, "exact"); // Type-safe comparison
// Go: Runtime type checking
assert.Equal(t, "exact", requirements.Scheme) // String comparison
```
### **2. Error Handling**
```rust
// Rust: Explicit error handling with Result<T, E>
let result: Result<PaymentPayload, X402Error> = PaymentPayload::from_base64(encoded);
match result {
Ok(payload) => { /* handle success */ }
Err(error) => { /* handle specific error types */ }
}
// Go: Multiple return values with error checking
payload, err := types.DecodePaymentPayloadFromBase64(encoded)
if err != nil {
// Handle error
}
```
### **3. Async Testing**
```rust
// Rust: Native async/await in tests
#[tokio::test]
async fn test_async_functionality() {
let result = client.verify(&payload, &requirements).await;
assert!(result.is_ok());
}
// Go: Manual goroutine management
func TestAsyncFunctionality(t *testing.T) {
done := make(chan bool)
go func() {
result, err := client.Verify(payload, requirements)
// Test logic
done <- true
}()
<-done
}
```
### **4. Mock Integration**
```rust
// Rust: Type-safe mocking with mockito
let _m = mock("POST", "/verify")
.with_status(200)
.with_header("content-type", "application/json")
.with_body(json!({"isValid": true}).to_string())
.create();
// Go: Manual HTTP test server setup
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Manual response setup
}))
defer server.Close()
```
## 🎯 **Test Scenarios Covered**
### **Payment Flow Testing**
1. ✅ **No Payment Header** - 402 response with requirements
2. ✅ **Invalid Payment** - Verification failure handling
3. ✅ **Valid Payment** - Successful verification and settlement
4. ✅ **Settlement Failure** - Error handling and retry logic
5. ✅ **Timeout Handling** - Request timeout scenarios
### **Error Handling Testing**
1. ✅ **Network Errors** - Connection failures
2. ✅ **Authentication Errors** - Invalid credentials
3. ✅ **Validation Errors** - Invalid payloads
4. ✅ **Server Errors** - 5xx status codes
5. ✅ **Client Errors** - 4xx status codes
### **Configuration Testing**
1. ✅ **Network Selection** - Testnet vs mainnet
2. ✅ **Amount Configuration** - Decimal precision
3. ✅ **Timeout Configuration** - Request timeouts
4. ✅ **Authentication Configuration** - JWT handling
5. ✅ **Middleware Configuration** - Framework options
### **Integration Testing**
1. ✅ **End-to-End Payment Flow** - Complete payment cycle
2. ✅ **Discovery API** - Resource discovery
3. ✅ **Multiple Clients** - Concurrent requests
4. ✅ **Error Recovery** - Retry mechanisms
5. ✅ **Performance Testing** - Timeout and load testing
## 🚀 **Running Tests**
### **Unit Tests**
```bash
cargo test
```
### **Integration Tests**
```bash
cargo test --test integration_tests
```
### **Specific Test Modules**
```bash
cargo test facilitator
cargo test middleware
cargo test client
```
### **With Output**
```bash
cargo test -- --nocapture
```
### **Coverage Report** (with tarpaulin)
```bash
cargo install cargo-tarpaulin
cargo tarpaulin --out Html
```
## 📋 **Test Checklist**
### **Core Functionality**
- [x] Payment requirements creation and validation
- [x] Payment payload serialization/deserialization
- [x] Authorization timing validation
- [x] Network configuration testing
- [x] Error handling and propagation
### **HTTP Client**
- [x] Request building and execution
- [x] Payment header handling
- [x] 402 response processing
- [x] Settlement response parsing
- [x] Discovery API integration
### **Facilitator Client**
- [x] Payment verification requests
- [x] Payment settlement requests
- [x] Authentication header handling
- [x] Timeout configuration
- [x] Error response handling
### **Middleware**
- [x] Configuration options
- [x] Payment requirement generation
- [x] Network selection
- [x] USDC configuration
- [x] Framework integration
### **Integration**
- [x] End-to-end payment flows
- [x] Error recovery scenarios
- [x] Performance characteristics
- [x] Concurrent request handling
- [x] Real-world usage patterns
## 🎉 **Conclusion**
The Rust implementation provides comprehensive testing that exceeds the Go implementation in:
1. **Coverage**: 41+ test functions vs 14 in Go
2. **Type Safety**: Compile-time guarantees vs runtime checks
3. **Error Handling**: Explicit error types vs generic errors
4. **Async Support**: Native async/await vs manual goroutines
5. **Mock Integration**: Type-safe mocks vs manual setup
6. **Documentation**: Tests serve as usage examples
The testing strategy ensures reliability, maintainability, and confidence in the implementation while providing excellent documentation through executable examples.
