[fdiff.utils] add get_tables_argument_list function

parses command line table request into list of table values

Author: chrissimpkins

lib/fdiff/utils.py

@@ -3,6 +3,11 @@
 from datetime import datetime, timezone
 
 
+def file_exists(path):
+    """Validates file path as existing local file"""
+    return os.path.isfile(path)
+
+
 def get_file_modtime(path):
     """Returns ISO formatted file modification time in local system timezone"""
     return (
@@ -12,6 +17,14 @@ def get_file_modtime(path):
     )
 
 
-def file_exists(path):
-    """Validates file path as existing local file"""
-    return os.path.isfile(path)
+def get_tables_argument_list(table_string):
+    """Converts a comma separated OpenType table string into a Python list or return None if
+    the table_string was not defined (i.e., it was not included in an option on the command line).
+    Tables that are composed of three characters must be right padded with a space."""
+    if table_string is None:
+        return None
+    else:
+        return [
+            table + " " if len(table) == 3 else table
+            for table in table_string.split(",")
+        ]

tests/test_utils.py

@@ -1,21 +1,30 @@
 import os
 import re
 
-from fdiff.utils import get_file_modtime, file_exists
+from fdiff.utils import get_file_modtime, get_tables_argument_list, file_exists
 
 import pytest
 
 
+def test_file_exists_true():
+    assert file_exists(os.path.join("tests", "testfiles", "test.txt")) is True
+
+
+def test_file_exists_false():
+    assert file_exists(os.path.join("tests", "testfiles", "bogus.jpg")) is False
+
+
 def test_get_file_modtime():
     modtime = get_file_modtime(os.path.join("tests", "testfiles", "test.txt"))
     assert modtime.startswith("2019-09-0") is True
     regex = re.compile(r"""\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+[-+]\d{2}:\d{2}""")
     assert regex.fullmatch(modtime) is not None
 
 
-def test_file_exists_true():
-    assert file_exists(os.path.join("tests", "testfiles", "test.txt")) is True
-
-
-def test_file_exists_false():
-    assert file_exists(os.path.join("tests", "testfiles", "bogus.jpg")) is False
+def test_get_tables_argument_list():
+    string1 = "head"
+    string2 = "head,post"
+    string3 = "head,post,cvt"
+    assert get_tables_argument_list(string1) == ["head"]
+    assert get_tables_argument_list(string2) == ["head", "post"]
+    assert get_tables_argument_list(string3) == ["head", "post", "cvt "]