Provide correct CustomerSubscriptions object when the 'subscriptions'…

… link is missing

Since the `CustomerSubscriptions` instance also provides access to creating a new
subscription, we need initialize it correctly at all times.

mollie/api/objects/customer.py

@@ -43,6 +43,8 @@ def created_at(self):
     @property
     def subscriptions(self):
         url = self._get_link("subscriptions")
+        if not url:
+            url = f"customers/{self.id}/subscriptions"
 
         from ..resources import CustomerSubscriptions
 
@@ -59,3 +61,8 @@ def payments(self):
         from ..resources import CustomerPayments
 
         return CustomerPayments(self.client, self)
+
+    # Additional methods
+
+    def has_subscriptions(self):
+        return self._get_link("subscriptions") is not None

tests/responses/customer_single_no_links.json

@@ -0,0 +1,23 @@
+{
+  "resource": "customer",
+  "id": "cst_8wmqcHMN4U",
+  "mode": "test",
+  "name": "Customer A",
+  "email": "customer@example.org",
+  "locale": "nl_NL",
+  "metadata": null,
+  "createdAt": "2018-04-06T13:23:21.0Z",
+  "_links": {
+    "self": {
+      "href": "https://api.mollie.com/v2/customers/cst_8wmqcHMN4U",
+      "type": "application/hal+json"
+    },
+    "mandates": null,
+    "subscriptions": null,
+    "payments": null,
+    "documentation": {
+      "href": "https://docs.mollie.com/reference/v2/customers-api/get-customer",
+      "type": "text/html"
+    }
+  }
+}

tests/responses/customer_subscriptions_list_empty.json

@@ -0,0 +1,20 @@
+{
+  "_embedded":{
+    "subscriptions":[
+
+    ]
+  },
+  "count":0,
+  "_links":{
+    "documentation":{
+      "href":"https://docs.mollie.com/reference/v2/subscriptions-api/list-subscriptions",
+      "type":"text/html"
+    },
+    "self":{
+      "href":"https://api.mollie.com/v2/customers/cst_tJs32TE8qk/subscriptions?limit=50",
+      "type":"application/hal+json"
+    },
+    "previous":null,
+    "next":null
+  }
+}

tests/test_customer_subscriptions.py

@@ -26,6 +26,19 @@ def test_list_customer_subscriptions(client, response):
     assert_list_object(subscriptions, Subscription)
 
 
+def test_list_customer_subscriptions_when_unavailable(client, response):
+    response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}", "customer_single_no_links")
+    response.get(
+        f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}/subscriptions",
+        "customer_subscriptions_list_empty",
+    )
+    customer = client.customers.get(CUSTOMER_ID)
+    assert customer.has_subscriptions() is False
+    # Now that we know that there are no subscriptions, we are still going to get them
+    subscriptions = customer.subscriptions.list()
+    assert_list_object(subscriptions, Subscription, 0)
+
+
 def test_get_customer_subscription(client, response):
     response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}", "customer_single")
     response.get(
@@ -142,7 +155,7 @@ def test_cancel_customer_subscription_invalid_id(client, response):
 
 def test_create_customer_subscription(client, response):
     """Create a subscription with customer object."""
-    response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}", "customer_single")
+    response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}", "customer_single_no_links")
     response.post(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}/subscriptions", "subscription_single")
 
     data = {