fix(docs): address API documentation inconsistencies

Fix several inconsistencies between official ATH Móvil API docs
and library documentation:

- Fix README code examples using incorrect field path
  (payment.data.ecommerce_id -> payment.ecommerce_id)
- Add critical disclaimer about no test environment available
- Add token expiration and lifecycle documentation
- Expand business account prerequisites with detailed requirements
- Remove unnecessary 'env' field from PaymentRequest model
- Update tests to remove Environment enum references

Addresses issues #8, #10, #13, and #15 from inconsistency audit.

Author: rnegron

README.md

@@ -54,10 +54,10 @@ payment = client.create_payment(
     ],
 )
 
-confirmed = client.wait_for_confirmation(payment.data.ecommerce_id)
+confirmed = client.wait_for_confirmation(payment.ecommerce_id)
 
 if confirmed:
-    result = client.authorize_payment(payment.data.ecommerce_id)
+    result = client.authorize_payment(payment.ecommerce_id)
     print(f"Payment completed: {result.data.reference_number}")
 ```
 

athm/models.py

@@ -17,12 +17,6 @@ class TransactionStatus(str, Enum):
     CANCEL = "CANCEL"
 
 
-class Environment(str, Enum):
-    """Available environments."""
-
-    PRODUCTION = "production"
-
-
 class PaymentItem(BaseModel):
     """Item in a payment request."""
 
@@ -69,7 +63,6 @@ class PaymentRequest(BaseModel):
 
     model_config = ConfigDict(populate_by_name=True)
 
-    env: Environment = Environment.PRODUCTION
     public_token: str = Field(..., alias="publicToken")
     timeout: str = Field(default="600")
     total: str

docs/installation.md

@@ -1,5 +1,36 @@
 # Installation
 
+!!! danger "No Test Environment Available"
+    **Important**: ATH Móvil does not provide a sandbox or test environment. All API calls are made to the production environment with real money transactions. You must have:
+
+    - An active ATH Business account with a registered payment card
+    - An active ATH Móvil personal account (separate from business account)
+    - Different payment cards for your business and personal accounts
+
+    When testing, you will create real payment requests that require actual confirmation and cancellation.
+
+## Prerequisites
+
+Before installing the library, ensure you have:
+
+### Required Accounts
+
+1. **ATH Business Account**
+   - Active merchant account with verified business information
+   - Registered payment card linked to the business account
+   - Access to ATH Business app or web portal for API credential management
+
+2. **ATH Móvil Personal Account**
+   - Active personal ATH Móvil account for testing
+   - Must use a **different payment card** than your business account
+   - Cannot use the same card for customer and merchant transactions (will trigger error BTRA_0003)
+
+### Technical Requirements
+
+- Python 3.10 or higher
+- Active internet connection (all API calls require HTTPS)
+- Secure environment for storing API credentials
+
 ## Install the Package
 
 ### Using pip
@@ -49,6 +80,22 @@ Once your account is verified:
 | **Public Token** | All payment operations | Create, check, authorize, cancel payments |
 | **Private Token** | Refunds only | Process refunds on completed payments |
 
+### Token Lifecycle and Expiry
+
+!!! warning "Token Expiration"
+    API tokens can expire after a period specified by ATH Business. When a token expires:
+
+    - You will receive error `token.expired` or `BTRA_0401`/`BTRA_0402`/`BTRA_0403`
+    - You must generate new tokens from the ATH Business portal
+    - No automatic token refresh is available
+
+**Best practices:**
+
+- Monitor for authentication errors in your application logs
+- Have a process to quickly rotate expired tokens
+- Store tokens securely using environment variables or secret managers
+- Never hardcode tokens in your source code
+
 ## Configure Environment Variables
 
 ### Create a `.env` file

tests/unit/test_models.py

@@ -8,7 +8,6 @@
 
 from athm.models import (
     APIError,
-    Environment,
     PaymentItem,
     PaymentRequest,
     PaymentResponse,
@@ -122,7 +121,6 @@ def test_valid_payment_request(self):
         assert request.public_token == "test_token"
         assert request.total == "100.00"
         assert request.phone_number == "7875551234"
-        assert request.env == Environment.PRODUCTION
 
     def test_payment_request_defaults(self):
         request = PaymentRequest(
@@ -132,7 +130,6 @@ def test_payment_request_defaults(self):
             items=[PaymentItem(name="Test", description="Test", quantity="1", price="100.00")],
         )
         assert request.timeout == "600"
-        assert request.env == Environment.PRODUCTION
         assert request.tax is None
         assert request.subtotal is None