diff --git a/tests/unit/providers/configuration/test_ini_files_in_init_py2_py3.py b/tests/unit/providers/configuration/test_ini_files_in_init_py2_py3.py
new file mode 100644
index 00000000..30d8606c
--- /dev/null
+++ b/tests/unit/providers/configuration/test_ini_files_in_init_py2_py3.py
@@ -0,0 +1,97 @@
+"""Configuration(ini_files=[...]) tests."""
+
+from dependency_injector import providers
+from pytest import fixture, mark, raises
+
+
+@fixture
+def config(config_type, ini_config_file_1, ini_config_file_2):
+    if config_type == "strict":
+        return providers.Configuration(strict=True)
+    elif config_type == "default":
+        return providers.Configuration(ini_files=[ini_config_file_1, ini_config_file_2])
+    else:
+        raise ValueError("Undefined config type \"{0}\"".format(config_type))
+
+
+def test_load(config):
+    config.load()
+
+    assert config() == {
+        "section1": {
+            "value1": "11",
+            "value11": "11",
+        },
+        "section2": {
+            "value2": "2",
+        },
+        "section3": {
+            "value3": "3",
+        },
+    }
+    assert config.section1() == {"value1": "11", "value11": "11"}
+    assert config.section1.value1() == "11"
+    assert config.section1.value11() == "11"
+    assert config.section2() == {"value2": "2"}
+    assert config.section2.value2() == "2"
+    assert config.section3() == {"value3": "3"}
+    assert config.section3.value3() == "3"
+
+
+def test_get_files(config, ini_config_file_1, ini_config_file_2):
+    assert config.get_ini_files() == [ini_config_file_1, ini_config_file_2]
+
+
+def test_set_files(config):
+    config.set_ini_files(["file1.ini", "file2.ini"])
+    assert config.get_ini_files() == ["file1.ini", "file2.ini"]
+
+
+def test_file_does_not_exist(config):
+    config.set_ini_files(["./does_not_exist.ini"])
+    config.load()
+    assert config() == {}
+
+
+@mark.parametrize("config_type", ["strict"])
+def test_file_does_not_exist_strict_mode(config):
+    config.set_ini_files(["./does_not_exist.ini"])
+    with raises(IOError):
+        config.load()
+    assert config() == {}
+
+
+def test_required_file_does_not_exist(config):
+    config.set_ini_files(["./does_not_exist.ini"])
+    with raises(IOError):
+        config.load(required=True)
+
+
+@mark.parametrize("config_type", ["strict"])
+def test_not_required_file_does_not_exist_strict_mode(config):
+    config.set_ini_files(["./does_not_exist.ini"])
+    config.load(required=False)
+    assert config() == {}
+
+
+def test_missing_envs_required(config, ini_config_file_3):
+    with open(ini_config_file_3, "w") as file:
+        file.write(
+            "[section]\n"
+            "undefined=${UNDEFINED}\n"
+        )
+    config.set_ini_files([ini_config_file_3])
+    with raises(ValueError, match="Missing required environment variable \"UNDEFINED\""):
+        config.load(envs_required=True)
+
+
+@mark.parametrize("config_type", ["strict"])
+def test_missing_envs_not_required_in_strict_mode(config, ini_config_file_3):
+    with open(ini_config_file_3, "w") as file:
+        file.write(
+            "[section]\n"
+            "undefined=${UNDEFINED}\n"
+        )
+    config.set_ini_files([ini_config_file_3])
+    config.load(envs_required=False)
+    assert config.section.undefined() == ""