Update tests and convert to stock unittest

For these simple tests Python's built-in unittest framework is more than enough.
No additional dependencies are required.

Added some more test cases with "special" characters to test the escaping code
better.

code/tests.py

@@ -1,27 +1,58 @@
-"""These tests can be run with pytest.
-This requires pytest: pip install pytest
-cd to the `code` directory and run `pytest`
-"""
+#!/usr/bin/env python3
+"""To run these tests just execute this script."""
 
 import json
-from pathlib import Path
+import unittest
 
 from robots import json_to_txt, json_to_table, json_to_htaccess
 
+class RobotsUnittestExtensions:
+    def loadJson(self, pathname):
+        with open(pathname, "rt") as f:
+            return json.load(f)
 
-def test_robots_txt_creation():
-    robots_json = json.loads(Path("test_files/robots.json").read_text())
-    robots_txt = json_to_txt(robots_json)
-    assert Path("test_files/robots.txt").read_text() == robots_txt
+    def assertEqualsFile(self, f, s):
+        with open(f, "rt") as f:
+            f_contents = f.read()
+
+        return self.assertMultiLineEqual(f_contents, s)
 
 
-def test_table_of_bot_metrices_md():
-    robots_json = json.loads(Path("test_files/robots.json").read_text())
-    robots_table = json_to_table(robots_json)
-    assert Path("test_files/table-of-bot-metrics.md").read_text() == robots_table
+class TestRobotsTXTGeneration(unittest.TestCase, RobotsUnittestExtensions):
+    maxDiff = 8192
+
+    def setUp(self):
+        self.robots_dict = self.loadJson("test_files/robots.json")
+
+    def test_robots_txt_generation(self):
+        robots_txt = json_to_txt(self.robots_dict)
+        self.assertEqualsFile("test_files/robots.txt", robots_txt)
 
 
-def test_htaccess_creation():
-    robots_json = json.loads(Path("test_files/robots.json").read_text())
-    robots_htaccess = json_to_htaccess(robots_json)
-    assert Path("test_files/.htaccess").read_text() == robots_htaccess
+class TestTableMetricsGeneration(unittest.TestCase, RobotsUnittestExtensions):
+    maxDiff = 32768
+
+    def setUp(self):
+        self.robots_dict = self.loadJson("test_files/robots.json")
+
+    def test_table_generation(self):
+        robots_table = json_to_table(self.robots_dict)
+        self.assertEqualsFile("test_files/table-of-bot-metrics.md", robots_table)
+
+
+class TestHtaccessGeneration(unittest.TestCase, RobotsUnittestExtensions):
+    maxDiff = 8192
+
+    def setUp(self):
+        self.robots_dict = self.loadJson("test_files/robots.json")
+
+    def test_htaccess_generation(self):
+        robots_htaccess = json_to_htaccess(self.robots_dict)
+        self.assertEqualsFile("test_files/.htaccess", robots_htaccess)
+
+
+if __name__ == "__main__":
+    import os
+    os.chdir(os.path.dirname(__file__))
+
+    unittest.main(verbosity=2)