Add tests

soundchanger/change.py

@@ -1,13 +1,60 @@
 import re
+import argparse
+
+
+__version__ = '0.1.0'
+
+
+def main():
+    """
+    CLI entry point of the program.
+    """
+
+    parser = argparse.ArgumentParser(prog="soundchanger")
+    parser.add_argument(
+        "changes",
+        help="Sound change to be applied. Multiple sound changes should be separated by a space."
+    )
+    parser.add_argument(
+        "strings",
+        help="Word that the sound change should be applied to. Multiple words should be separated by a space."
+    )
+    parser.add_argument(
+        "-C", "--categories",
+        default={},
+        help="Categories to be used in the sound change."
+    )
+    parser.add_argument(
+        "-i", "--ignore-errors",
+        action="store_false",
+        help="Categories to be used in the sound change."
+    )
+    parser.add_argument(
+        "-z", "--zero-characters",
+        default='∅-',
+        help="Characters that should be empty strings in the changed words."
+    )
+    parser.add_argument(
+        "-v", "--version",
+        action="version",
+        version=f"%(prog)s {__version__}"
+    )
+    args = parser.parse_args()
+    print(apply(
+        args.changes.split(),
+        args.strings.split(),
+        args.categories,
+        args.ignore_errors,
+        args.zero_characters
+    ))
 
 
 def apply(
         changes,
         strings,
-    apply=True,
         categories={},
         ignore_errors=True,
-    zero_characters=['∅']):
+        zero_characters='∅-'):
     """
     Applies a sound change or a list of sound changes to a string or
     a list of given strings.
@@ -16,22 +63,19 @@ def apply(
     If the input value is of type str, the output will also be of type str.
 
     Options:
-      - apply (default: True)
-            Whether or not the changes should be applied.
       - categories (default: {})
             Which categories will be detected.
             For vowels it would be {'V'='aeiou'} or {'V'=['a', 'e', 'i', 'o', 'u']})
+
       - ignore_errors (default: True)
             If this option is set to `True`, any erroneous sound change will be skipped.
-            If set to `False`, a ValueError will be raised.
-      - zero_characters (default: ['∅'])
+            If set to `False`, a ValueError will be raised instead.
+
+      - zero_characters (default: '∅-')
             These characters will be removed in the changed words.
             For example, `apply('h>∅', 'aha')` will return 'aa', not 'a∅a'.
     """
 
-    if not apply:
-        return strings
-
     if isinstance(changes, str):
         changes = [changes]
 
@@ -42,10 +86,10 @@ def apply(
         strings = strings.copy()
 
     for change in changes:
-        if validate_change(change, ignore_errors=ignore_errors) == False:
+        if is_valid_change(change, ignore_errors=ignore_errors) == False:
             continue
 
-        change = convert_change_to_regex(change, categories=categories, zero_characters=zero_characters)
+        change = reformat_change_to_regex(change, categories=categories, zero_characters=zero_characters)
         original, change_to, before, after = split_change(change)
 
         pattern = f"({before})({original})({after})"
@@ -60,8 +104,15 @@ def apply(
     return strings
 
 
-def validate_change(change, ignore_errors):
-    valid = re.search(r'^[^>_/]+?>[^>_/]*?(:?/[^>_/]*?_+[^>_/]*)?$', change)
+def is_valid_change(change, ignore_errors=True):
+    """
+    Returns `True` if the change is valid.
+    If the change is not valid, it returns `False`
+    unless `ignore_errors` is set to `False`,
+    in which case it raises a ValueError.
+    """
+
+    valid = re.search(r'^[^>_/]+?>[^>_/]*?/?(:?[^>_/]*?_+[^>_/]*)?$', change)
     if ignore_errors:
         return valid != None
     if not valid:
@@ -69,7 +120,14 @@ def validate_change(change, ignore_errors):
     return True
 
 
-def convert_change_to_regex(change, categories, zero_characters):
+def reformat_change_to_regex(change, categories={}, zero_characters='∅-'):
+    """
+    Reformats a sound change for use in regular expressions.
+    Replaces mentions of categories with their actual values
+    and removes all zero characters.
+    Returns the reformatted change.
+    """
+
     # Prepare change for regex
     for k, v in {' ': '', '{': '(', '}': ')', ',': '|'}.items():
         change = change.replace(k, v)
@@ -89,15 +147,33 @@ def convert_change_to_regex(change, categories, zero_characters):
 
 
 def split_change(change):
+    """
+    Splits a valid change into four components.
+
+    Syntax:
+        original > change_to / before __ after
+       ╰────── Change ──────╯ ╰─ Environment ─╯
+
+    Returns a tuple of the four components:
+        (original, change_to, before, after)
+    """
+
     if '/' in change:
         change, environment = change.split('/')
     else:
         environment = '_'
 
-    # Collaplse multiple underscores
+    # Collapse multiple underscores
     environment = re.sub('_+', '_', environment)
 
     original, change_to = change.split('>')
+    if '_' in environment:
         before, after = environment.split('_')
+    else:
+        before = after = ''
 
     return (original, change_to, before, after)
+
+
+if __name__ == '__main__':
+    main()

tests/test_is_valid_change.py

@@ -0,0 +1,32 @@
+from soundchanger.change import is_valid_change
+import pytest
+
+def test_valid_change():
+    assert is_valid_change('a>b/c_d') == True
+    assert is_valid_change('a>b/c__d') == True
+    assert is_valid_change('a>b/c_') == True
+    assert is_valid_change('a>b/_d') == True
+    assert is_valid_change('a>b') == True
+    assert is_valid_change('a>b/_') == True
+    assert is_valid_change('a>b/') == True
+
+def test_invalid_change():
+    assert is_valid_change('>') == False
+    assert is_valid_change('>b') == False
+    assert is_valid_change('a>b/a') == False
+    assert is_valid_change('>/_') == False
+    assert is_valid_change('a>b//c_d') == False
+
+def test_raises_value_error():
+    with pytest.raises(ValueError):
+        is_valid_change('>', ignore_errors=False)
+    with pytest.raises(ValueError):
+        is_valid_change('>', ignore_errors=False)
+    with pytest.raises(ValueError):
+        is_valid_change('>b', ignore_errors=False)
+    with pytest.raises(ValueError):
+        is_valid_change('a>b/a', ignore_errors=False)
+    with pytest.raises(ValueError):
+        is_valid_change('>/_', ignore_errors=False)
+    with pytest.raises(ValueError):
+        is_valid_change('a>b//c_d', ignore_errors=False)

tests/test_reformat_change_to_regex.py

@@ -0,0 +1,21 @@
+from soundchanger.change import reformat_change_to_regex
+
+
+def test_replace_spaces():
+    assert reformat_change_to_regex(' a > b / c _ d ') == 'a>b/c_d'
+
+def test_replace_brackets_and_commas():
+    assert reformat_change_to_regex('a>b/{#,a}_') == 'a>b/(#|a)_'
+
+def test_replace_categories():
+    assert reformat_change_to_regex('a>b/V_',
+        categories={'V': 'aiu'}
+    ) == 'a>b/(a|i|u)_'
+
+def test_replace_categories_in_brackets():
+    assert reformat_change_to_regex('a>b/{#,V}_',
+        categories={'V': 'aiu'}
+    ) == 'a>b/(#|(a|i|u))_'
+
+def test_replace_zero_characters():
+    assert reformat_change_to_regex('a>∅') == 'a>'

tests/test_split_change.py

@@ -0,0 +1,34 @@
+from soundchanger.change import split_change
+import pytest
+
+
+def test_simple_change():
+    assert split_change('a>b') == ('a', 'b', '', '')
+
+def test_change_with_slash():
+    assert split_change('a>b/') == ('a', 'b', '', '')
+
+def test_change_with_environment():
+    assert split_change('a>b/c_d') == ('a', 'b', 'c', 'd')
+
+def test_change_with_environment_double_underscore():
+    assert split_change('a>b/c__d') == ('a', 'b', 'c', 'd')
+
+def test_change_with_environment_before():
+    assert split_change('a>b/#_') == ('a', 'b', '#', '')
+
+def test_change_with_environment_after():
+    assert split_change('a>b/_#') == ('a', 'b', '', '#')
+
+def test_change_with_empty_environment():
+    assert split_change('a>b/_') == ('a', 'b', '', '')
+
+def test_change_to_nothing():
+    assert split_change('a>') == ('a', '', '', '')
+
+def test_change_to_zero():
+    assert split_change('a>-') == ('a', '-', '', '')
+
+def test_invalid_input():
+    with pytest.raises(ValueError):
+        assert split_change('')