diff --git a/tests/test_example.py b/tests/test_example.py
index 52be4c1..2326a55 100644
--- a/tests/test_example.py
+++ b/tests/test_example.py
@@ -1,7 +1,8 @@
 import mypy2junit
 
 def test_example():
-    lines = open('tests/mypy.txt').readlines()
+    with open('tests/mypy.txt') as file:
+        lines = file.readlines()
     res, _ = mypy2junit.process_lines(lines)
 
     assert res == """<?xml version="1.0" encoding="utf-8"?>
@@ -21,7 +22,8 @@ def test_example():
 </testsuite>"""
 
 def test_example_one():
-    lines = open('tests/mypy_one.txt').readlines()
+    with open('tests/mypy_one.txt') as file:
+        lines = file.readlines()
     res, _ = mypy2junit.process_lines(lines)
 
     assert res == """<?xml version="1.0" encoding="utf-8"?>
@@ -33,7 +35,8 @@ def test_example_one():
 
 
 def test_success():
-    lines = open('tests/mypy_success.txt').readlines()
+    with open('tests/mypy_success.txt') as file:
+        lines = file.readlines()
     res, _ = mypy2junit.process_lines(lines)
 
     assert res == """<?xml version="1.0" encoding="utf-8"?>