Made the parser more verbose and added some comments for comprehension.

.gitignore

@@ -3,3 +3,4 @@ __pycache__
 
 .dir-locals.el
 .#*
+*.egg-info

ssh_config_utils/parser.py

@@ -13,7 +13,17 @@ KEYWORDS_LOWER_TRANSLATE = dict(zip(KEYWORDS_LOWER, KEYWORDS))
 HOST_SPLITTER = re.compile(
     r"host(?:.(?!\bhost\b))+", flags=re.MULTILINE | re.DOTALL | re.IGNORECASE
 )
-KEY_VALUE = re.compile(r"(?P<key>\S+)(?:[ \t]+|[ \t]*=[ \t]*)(?P<values>.*)")
+KEY_VALUE = re.compile(
+    r"""
+(?P<key>\S+) #anything that isn't a space is part of the key
+(?:
+    [ \t]+ #seperated by whitespace
+    |
+    [ \t]*=[ \t]* #seperated by equals
+)
+(?P<values>.*)""",
+    re.VERBOSE,
+)
 
 
 def CamelCase_to_snake(text):  # noqa
@@ -21,13 +31,16 @@ def CamelCase_to_snake(text):  # noqa
 
 
 def parse_config_text(text):
+    # Step 0: strip leaing whitespaces and comments
     text_no_leading_whitespace = re.sub(r"^[ \t]+", "", text, flags=re.MULTILINE)
     text_no_comments = re.sub(
         r"^\#.*", "", text_no_leading_whitespace, flags=re.MULTILINE
     )
+    # Step 1: split file by Host blocks
     hosts = HOST_SPLITTER.finditer(text_no_comments)
     for host in hosts:
         host_dict = {}
+        # Step 2: go line by line looking for key=value
         for line in host.group(0).split("\n"):
             match = KEY_VALUE.match(line)
             if match:

tests/tests.py

@@ -2,6 +2,7 @@ import os
 import sys
 import unittest
 import tempfile
+from ssh_config_utils.parser import CamelCase_to_snake
 
 samples_dir = os.path.join(sys.path[0], "sample_configs")
 CONFIG_FILES = dict(
@@ -25,4 +26,10 @@ class TestTempFile(ReadWriteTest):
 
 
 class TestParser(ReadWriteTest):
-    pass
+    def test_camel_case_to_snake_case(self):
+        initial_vals = "ThisIsCamelCase", "This"
+        expected_vals = "this_is_camel_case", "this"
+
+        for initial, expected in zip(initial_vals, expected_vals):
+            with self.subTest(initial=initial, expected=expected):
+                self.assertEqual(CamelCase_to_snake(initial), expected)