zaelcovsky · October 23, 2023 19:22 · Sep 19, 2018 · Sep 19, 2018 · Sep 19, 2018 · Sep 19, 2018
diff --git a/function.py b/function.py
@@ -1,3 +1,4 @@
+# Python 3.7
 import json
 from typing import List
 

diff --git a/tests.py b/tests.py
@@ -1,3 +1,4 @@
+# Python 3.7
 import unittest
 import unittest.mock
 

diff --git a/_mock_file_with_string.md b/_mock_file_with_string.md
@@ -16,5 +16,5 @@ Example with `@mock_patch` decorator and corresponding function are shown.
 
 ## Sources
 
-- [`mock.open`](https://docs.python.org/3/library/unittest.mock.html#mock-open)
+- [`mock_open`](https://docs.python.org/3/library/unittest.mock.html#mock-open)
 - [Michele d'Amico's answer on: How do I mock an open used in a with statement (using the Mock framework in Python)?](https://stackoverflow.com/a/34677735)
diff --git a/mock_file_with_string.md → _mock_file_with_string.md b/mock_file_with_string.md → _mock_file_with_string.md
diff --git a/README.md → mock_file_with_string.md b/README.md → mock_file_with_string.md
diff --git a/README.md b/README.md
@@ -0,0 +1,20 @@
+# Mock file with string in Python
+
+This is an example on how to mock a file with string.
+
+## Use case
+
+Testing a function which opens a file and does some kind of operation on it.
+
+## About the example
+
+Let us make a function which takes json from file and returns some data. In this example, we want to take data from [this API](https://www.edsm.net/api-system-v1/bodies?systemName=Sol) and return name of each planet and its surface temperature in a list.
+
+Instead of creating a mock file, we can limit ourselves to short string with only necessary information.
+
+Example with `@mock_patch` decorator and corresponding function are shown.
+
+## Sources
+
+- [`mock.open`](https://docs.python.org/3/library/unittest.mock.html#mock-open)
+- [Michele d'Amico's answer on: How do I mock an open used in a with statement (using the Mock framework in Python)?](https://stackoverflow.com/a/34677735)
diff --git a/function.py b/function.py
@@ -0,0 +1,14 @@
+import json
+from typing import List
+
+
+def celestial_bodies_temperatures(filename: str) -> List(List(str, int)):
+    return_list = []
+    with open(filename) as f:
+        data = json.load(f)
+        for each_planet in data:
+            return_list.append(
+                [each_planet["name"],
+                 int(each_planet["surfaceTemperature"])]
+            )
+    return return_list
diff --git a/tests.py b/tests.py
@@ -0,0 +1,33 @@
+import unittest
+import unittest.mock
+
+from .function import celestial_bodies_temperatures
+
+
+class TestFunction(unittest.TestCase):
+    mock_file_content = """
+    [{"name": "Earth","surfaceTemperature": 288},
+    {"name": "Mars", "surfaceTemperature": 260}]
+    """
+
+    def test_celestial_bodies_temperatures_returns_list_correctly_with(self):
+        with unittest.mock.patch(
+                'builtins.open',
+                new=unittest.mock.mock_open(read_data=self.mock_file_content),
+                create=True
+        ) as file_mock:
+            self.assertEqual(
+                celestial_bodies_temperatures('/dev/null'),
+                [["Earth", 288], ["Mars", 260]]
+            )
+
+    @unittest.mock.patch(
+        'builtins.open',
+        new=unittest.mock.mock_open(read_data=mock_file_content),
+        create=True
+    )
+    def test_celestial_bodies_temperatures_returns_list_correctly_decorator(self):
+        self.assertEqual(
+            celestial_bodies_temperatures('/dev/null'),
+            [["Earth", 288], ["Mars", 260]]
+        )
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