Fix StripeError http_body

stripe/_error.py

@@ -26,14 +26,20 @@ def __init__(
         super(StripeError, self).__init__(message)
 
         body: Optional[str] = None
-        if http_body and hasattr(http_body, "decode"):
-            try:
-                body = cast(bytes, http_body).decode("utf-8")
-            except BaseException:
-                body = (
-                    "<Could not decode body as utf-8. "
-                    "Please report to support@stripe.com>"
-                )
+        if http_body:
+            # http_body can sometimes be a memoryview which must be cast
+            # to a "bytes" before calling decode, so we check for the
+            # decode attribute and then cast
+            if hasattr(http_body, "decode"):
+                try:
+                    body = cast(bytes, http_body).decode("utf-8")
+                except BaseException:
+                    body = (
+                        "<Could not decode body as utf-8. "
+                        "Please report to support@stripe.com>"
+                    )
+            elif isinstance(http_body, str):
+                body = http_body
 
         self._message = message
         self.http_body = body

tests/test_error.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 
+import json
 from stripe import error
 
 
@@ -28,6 +29,22 @@ def test_repr(self):
             "request_id='123')"
         )
 
+    def test_error_string_body(self):
+        http_body = '{"error": {"code": "some_error"}}'
+        err = error.StripeError(
+            "message", http_body=http_body, json_body=json.loads(http_body)
+        )
+        assert err.http_body is not None
+        assert err.http_body == json.dumps(err.json_body)
+
+    def test_error_bytes_body(self):
+        http_body = '{"error": {"code": "some_error"}}'.encode("utf-8")
+        err = error.StripeError(
+            "message", http_body=http_body, json_body=json.loads(http_body)
+        )
+        assert err.http_body is not None
+        assert err.http_body == json.dumps(err.json_body)
+
     def test_error_object(self):
         err = error.StripeError(
             "message", json_body={"error": {"code": "some_error"}}