diff --git a/tests.py b/tests.py
index 7bec774..a0af73f 100644
--- a/tests.py
+++ b/tests.py
@@ -45,8 +45,21 @@ def test_pipes_isfifo(pipe_io):
     ]
 )
 def test_io(pipe_io, test_data):
-    File(pipe_io.in_pipe, string=True).write(test_data)
-    assert File(pipe_io.out_pipe, string=True).read() == test_data
+    File(pipe_io.in_pipe).write(test_data.encode())
+    assert File(pipe_io.out_pipe).read().decode() == test_data
+
+
+class File:
+    def __init__(self, path):
+        self.path = path
+
+    def write(self, what):
+        with open(self.path, 'wb') as ofile:
+            ofile.write(what)
+
+    def read(self):
+        with open(self.path, 'rb') as ifile:
+            return ifile.read()
 
 
 @pytest.mark.parametrize(
@@ -61,33 +74,19 @@ def test_io(pipe_io, test_data):
     ]
 )
 def test_io_large_data(pipe_io, test_data_size):
-    random_data = urandom(test_data_size)
-    File(pipe_io.in_pipe).write(random_data)
-    assert File(pipe_io.out_pipe).read() == random_data
+    test_data = urandom(test_data_size)
+    File(pipe_io.in_pipe).write(test_data)
+    assert File(pipe_io.out_pipe).read() == test_data
 
 
 def test_io_stress(pipe_io):
     for _ in range(2222):
-        random_data = urandom(randint(1, 1024))
-        File(pipe_io.in_pipe).write(random_data)
-        assert File(pipe_io.out_pipe).read() == random_data
+        test_data = urandom(randint(1, 1024))
+        File(pipe_io.in_pipe).write(test_data)
+        assert File(pipe_io.out_pipe).read() == test_data
 
 
 def test_stop_removes_pipes(pipe_io):
     pipe_io.stop()
     for path in (pipe_io.in_pipe, pipe_io.out_pipe):
         assert not exists(path)
-
-
-class File:
-    def __init__(self, path, string=False):
-        self.path = path
-        self._filemode = '' if string else 'b'
-
-    def write(self, what):
-        with open(self.path, f'w{self._filemode}') as ofile:
-            ofile.write(what)
-
-    def read(self):
-        with open(self.path, f'r{self._filemode}') as ifile:
-            return ifile.read()