Fix failing Travis build due to issues 39-45

.travis.yml

@@ -6,10 +6,12 @@ python:
 - 3.8
 
 before_install:
-- pip install poetry
+- curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py > /tmp/get-poetry.py
+- python /tmp/get-poetry.py --preview --yes
+- source $HOME/.poetry/env
 
 install:
-- poetry install -E yaml -E toml -E azure -E aws
+- poetry install -E yaml -E toml -E azure -E aws -E gcp
 
 script:
 - poetry run pytest

config/configuration.py

@@ -3,6 +3,7 @@
 import base64
 from contextlib import contextmanager
 from copy import deepcopy
+from sys import version_info
 from typing import (
     Any,
     Dict,
@@ -27,6 +28,9 @@
     interpolate_object,
 )
 
+if version_info < (3, 8):
+    from collections import OrderedDict
+
 
 class Configuration:
     """
@@ -299,7 +303,10 @@ def __iter__(self) -> Iterator[Tuple[str, Any]]:  # noqa: D105
         return iter(dict(self.items()))  # type: ignore
 
     def __reversed__(self) -> Iterator[Tuple[str, Any]]:  # noqa: D105
-        return reversed(dict(self.items()))  # type: ignore
+        if version_info < (3, 8):
+            return OrderedDict(reversed(list(self.items())))  # type: ignore
+        else:
+            return reversed(dict(self.items()))  # type: ignore
 
     def __len__(self) -> int:  # noqa: D105
         return len(self.keys())

tests/test_interpolation.py

@@ -46,7 +46,10 @@ def test_interpolation():  # type: ignore
     assert cfg.var1 == "This is a test"
 
     cfg = config_from_dict(
-        VALUES, lowercase_keys=True, interpolate=True, interpolate_type="unknown",
+        VALUES,
+        lowercase_keys=True,
+        interpolate=True,
+        interpolate_type="unknown",
     )
 
     with raises(ValueError, match='Invalid interpolation method "unknown"'):