Implement basic test cases

tests.py

@@ -0,0 +1,52 @@
+from os import stat
+from os.path import exists
+from stat import S_ISFIFO
+
+import pytest
+
+from echo_server import EchoPipeIOServer
+
+
+@pytest.fixture
+def pipe_io():
+    pipe_server = EchoPipeIOServer()
+    pipe_server.run()
+    yield pipe_server
+    pipe_server.stop()
+
+
+def test_pipes_exist(pipe_io):
+    for path in (pipe_io.in_pipe, pipe_io.out_pipe):
+        assert exists(path)
+
+
+def test_pipes_isfifo(pipe_io):
+    for path in (pipe_io.in_pipe, pipe_io.out_pipe):
+        assert S_ISFIFO(stat(path).st_mode)
+
+
+@pytest.mark.parametrize(
+    'test_data', [
+        'cats',
+        'cheese',
+        'You ever wonder why we are here?',
+        'Lorem ipsum dolor sit amet',
+        'You always have a plan, Dutch!'
+    ]
+)
+def test_echo_server(pipe_io, test_data):
+    File(pipe_io.in_pipe).write(test_data)
+    assert File(pipe_io.out_pipe).read() == test_data
+
+
+class File:
+    def __init__(self, path):
+        self.path = path
+
+    def write(self, what):
+        with open(self.path, 'w') as ofile:
+            ofile.write(what)
+
+    def read(self):
+        with open(self.path, 'r') as ifile:
+            return ifile.read()