Testing __init__ method in a Class

nice-scripts/mock_an__init__method_a_class.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+#-*- coding:utf-8 -*-
+"""
+source : https://medium.com/@george.shuklin/mocking-complicated-init-in-python-6ef9850dd202
+"""
+
+
+class Compl(object):
+    def __init__(self, arg1, arg2):
+        self.var1 = complicated_to_mock(arg1)
+        self.var2 = self.var2.complicated_to_mocK2(arg2)
+
+        if self.var1 in self.var2 and self.var1 != self.var2:
+            self.var3 = self.var2 - self.var1 + ctm3(ctm4())
+
+        self.foo  = {
+            "1": {"price": "2.7", "quantity": "10"},
+            "2": {"price": "8.0", "quantity": "2"},
+        }
+
+    def simple(self, arg3):
+        if arg3 > self.var1:
+            return None
+        else:
+            return arg3 - self.var1
+
+
+from unittest.mock import patch
+
+def test_simple_none():
+    with patch.object(Compl, "__init__", lambda x, y, z: None):
+        c = Compl(None, None)
+        c.var1 = 0
+        c.foo = {"foo":"bar", "FOO":"BAR"}
+        assert c.simple(1) is None
+        assert [i for i in c.foo.keys()] == ["foo", "FOO"]
+
+def test_simple_substraction():
+    with patch.object(Compl, "__init__", lambda x, y, z: None):
+        c = Compl(None, None)
+        c.var1 = 1
+        assert c.simple(1) == 0