From 0b3e72109c0b858a9a65c64c9ed6424a76e105e3 Mon Sep 17 00:00:00 2001
From: Denis Fedoseev <denis@fedoseev.work>
Date: Mon, 9 Oct 2023 01:10:37 +0300
Subject: [PATCH] =?UTF-8?q?=D0=A0=D0=B5=D1=84=D0=B0=D0=BA=D1=82=D0=BE?=
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---
 command_parser/__init__.py   | 28 +++++++++++++------
 tests/test_command_parser.py | 54 ++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 8 deletions(-)
 create mode 100644 tests/test_command_parser.py

diff --git a/command_parser/__init__.py b/command_parser/__init__.py
index e10f3b0..c1ef871 100644
--- a/command_parser/__init__.py
+++ b/command_parser/__init__.py
@@ -1,13 +1,25 @@
+import re
+
+
 class CommandParser:
     @staticmethod
     def parse(command_string):
-        parsed_command = command_string.split('_')
 
-        command = parsed_command[0]
-        value = parsed_command[1]
+        if not command_string:
+            raise ValueError("Empty command received!")
 
-        match command:
-            case 'GET':
-                return {'command': command, 'value': value}
-            case _:
-                raise ValueError("Unknown command: "+command)
+        if not isinstance(command_string, str):
+            raise ValueError("Command must be a sting!")
+
+        if re.search('[^a-zA-Z0-9_\-]', command_string):
+            raise ValueError('Only [a-zA-Z0-9_\-] allowed')
+
+        if re.search('^GET_.*', command_string):
+            parsed_command = command_string.split('_', 1)
+
+            command = parsed_command[0]
+            value = parsed_command[1]
+
+            return {'command': command, 'value': value}
+        else:
+            raise ValueError("Unknown command: " + command_string)
diff --git a/tests/test_command_parser.py b/tests/test_command_parser.py
new file mode 100644
index 0000000..ef4e09f
--- /dev/null
+++ b/tests/test_command_parser.py
@@ -0,0 +1,54 @@
+import unittest
+from command_parser import CommandParser
+
+
+class TestCommandParser(unittest.TestCase):
+    def test_empty_line(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse('')
+
+        self.assertEqual('Empty command received!', str(context.exception))
+
+    def test_unknown_command(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse('REALLY_UNKNOWN_COMMAND')
+
+        self.assertEqual('Unknown command: REALLY_UNKNOWN_COMMAND', str(context.exception))
+
+    def test_parse_get_command(self):
+        result = CommandParser.parse('GET_A')
+
+        self.assertEqual(result, {'command': 'GET', 'value': 'A'})
+
+    def test_parse_get_command_w_dual_underlines(self):
+        result = CommandParser.parse('GET_A_B')
+
+        self.assertEqual(result, {'command': 'GET', 'value': 'A_B'})
+
+    def test_invalid_command(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse('NOT_GET_A')
+
+        self.assertEqual('Unknown command: NOT_GET_A', str(context.exception))
+
+    def test_invalid_command_string_type(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse(b'some_cmd')
+
+        self.assertEqual('Command must be a sting!', str(context.exception))
+
+    def test_not_allowed_symbols_in_command_string(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse('GET_!')
+
+        self.assertEqual('Only [a-zA-Z0-9_\-] allowed', str(context.exception))
+
+    def test_not_allowed_newline_in_command_string(self):
+        with self.assertRaises(ValueError) as context:
+            CommandParser.parse("GET_A\nGET_B")
+
+        self.assertEqual('Only [a-zA-Z0-9_\-] allowed', str(context.exception))
+
+
+if __name__ == '__main__':
+    unittest.main()