new parse_fraction function for simple fractions added with test data

number_parser/__init__.py

@@ -1 +1 @@
-from number_parser.parser import parse, parse_number, parse_ordinal
+from number_parser.parser import parse, parse_number, parse_ordinal, parse_fraction

number_parser/parser.py

@@ -267,6 +267,38 @@ def parse_number(input_string, language=None):
         return int(number_built[0])
     return None
 
+def parse_fraction(input_string, language=None):
+    """Converts a single number written in fraction to a numeric type"""
+    if not input_string.strip():
+        return None
+
+    if language is None:
+        language = _valid_tokens_by_language(input_string)
+
+    if language != 'en':
+        raise ValueError(f'"{language}" is not a supported language for parsing fraction')
+
+    fraction_separators = ["divided by", "over", "by", "/"]
+
+    for separator in fraction_separators:
+        position_of_separator = input_string.find(separator)
+
+        if position_of_separator == -1:
+            continue
+
+        string_before_separator = input_string[:position_of_separator]
+        string_after_separator = input_string[position_of_separator + len(separator):]
+
+        number_before_separator = parse_number(string_before_separator, language)
+        number_after_separator = parse_number(string_after_separator, language)
+
+        if number_before_separator == None or number_after_separator == None:
+            return None
+
+        return str(number_before_separator) + '/' + str(number_after_separator)
+
+    return None
+
 
 def parse(input_string, language=None):
     """

tests/test_number_parsing.py

@@ -1,5 +1,5 @@
 import pytest
-from number_parser import parse, parse_number
+from number_parser import parse, parse_number, parse_fraction
 from number_parser.parser import LanguageData, parse_ordinal
 
 
@@ -121,6 +121,33 @@ def test_parse_sentences_ordinal(expected, test_input, lang):
     assert parse(test_input, lang) == expected
 
 
+
+@pytest.mark.parametrize(
+    "test_input,expected,lang",
+    [
+        # empty / not-a-number
+        ('', None, None),
+        ('example of sentence', None, None),
+        # numeric
+        ('32', None, None),
+        (' 3 ', None, None),
+        # en
+        ('eleven', None, 'en'),
+        ('one hundred and forty two by a sentence', None, 'en'),
+        ('sentence / eleven', None, 'en'),
+        ('one hundred and forty two by eleven', '142/11', 'en'),
+        ('one hundred and forty two divided by eleven', '142/11', 'en'),
+        ('one hundred and forty two / eleven', '142/11', 'en'),
+        ('one hundred and forty two over eleven', '142/11', 'en'),
+        ('two million three thousand and nineteen/two thousand and nineteen', '2003019/2019', 'en'),
+        ('billion over nineteen billion and nineteen', '1000000000/19000000019', 'en'),
+
+    ]
+)
+def test_parse_fraction(expected, test_input, lang):
+    assert parse_fraction(test_input, language=lang) == expected
+
+
 def test_LanguageData_unsupported_language():
     with pytest.raises(ValueError):
         LanguageData('xxxx')