Dataset_generator + tests

synthetic_data/dataset_generator.py

@@ -0,0 +1,91 @@
+"""Contains generator that returns collective df of requested distinct generators."""
+
+import copy
+from typing import List, Optional
+
+import numpy as np
+import pandas as pd
+from numpy.random import Generator
+
+from synthetic_data.distinct_generators.categorical_generator import random_categorical
+from synthetic_data.distinct_generators.datetime_generator import random_datetimes
+from synthetic_data.distinct_generators.float_generator import random_floats
+from synthetic_data.distinct_generators.int_generator import random_integers
+from synthetic_data.distinct_generators.text_generator import random_string, random_text
+
+
+def convert_data_to_df(
+    np_data: np.array,
+    path: Optional[str] = None,
+    index: bool = False,
+    column_names: Optional[List[str]] = None,
+) -> pd.DataFrame:
+    """
+    Convert np array to a pandas dataframe.
+
+    :param np_data: np array to be converted
+    :type np_data: numpy array
+    :param path: path to output a csv of the dataframe generated
+    :type path: str, None, optional
+    :param index: whether to include index in output to csv
+    :type path: bool, optional
+    :param column_names: The names of the columns of a dataset
+    :type path: List, None, optional
+    :return: a pandas dataframe
+    """
+    # convert array into dataframe
+    if not column_names:
+        column_names = [x for x in range(len(np_data))]
+    dataframe = pd.DataFrame.from_dict(dict(zip(column_names, np_data)))
+    # save the dataframe as a csv file
+    if path:
+        dataframe.to_csv(path, index=index, encoding="utf-8")
+    return dataframe
+
+
+def generate_dataset_by_class(
+    rng: Generator,
+    columns_to_generate: List[dict],
+    dataset_length: int = 100000,
+    path: Optional[str] = None,
+) -> pd.DataFrame:
+    """
+    Randomizes a dataset with a mixture of different data classes.
+
+    :param rng: the np rng object used to generate random values
+    :type rng: numpy Generator
+    :param columns_to_generate: Classes of data to be included in the dataset
+    :type columns_to_generate: List[dict], None, optional
+    :param dataset_length: length of the dataset generated, default 100,000
+    :type dataset_length: int, optional
+    :param path: path to output a csv of the dataframe generated
+    :type path: str, None, optional
+
+    :return: pandas DataFrame
+    """
+    gen_funcs = {
+        "integer": random_integers,
+        "float": random_floats,
+        "categorical": random_categorical,
+        "text": random_text,
+        "datetime": random_datetimes,
+        "string": random_string,
+    }
+
+    if not columns_to_generate:
+        raise ValueError(
+            "columns_to_generate is empty and would result in an empty dataframe."
+        )
+
+    dataset = []
+    column_names = []
+    for col in columns_to_generate:
+        col_ = copy.deepcopy(col)
+        col_generator = col_.pop("generator")
+        if col_generator not in gen_funcs:
+            raise ValueError(f"generator: {col_generator} is not a valid generator.")
+
+        col_generator_function = gen_funcs.get(col_generator)
+        dataset.append(col_generator_function(rng=rng, num_rows=dataset_length))
+        column_names.append(col_generator)
+    return convert_data_to_df(dataset, path, column_names=column_names)

synthetic_data/distinct_generators/categorical_generator.py

@@ -8,8 +8,8 @@
 def random_categorical(
     rng: Generator,
     categories: Optional[List[str]] = None,
-    num_rows: int = 1,
     probabilities: Optional[List[float]] = None,
+    num_rows: int = 1,
 ) -> np.array:
     """
     Randomly generates an array of categorical values chosen out of categories.

synthetic_data/distinct_generators/datetime_generator.py

@@ -9,8 +9,8 @@
 def generate_datetime(
     rng: Generator,
     date_format: str,
-    start_date: pd.Timestamp = pd.Timestamp(1920, 1, 1),
-    end_date: pd.Timestamp = pd.Timestamp(2049, 12, 31),
+    start_date: pd.Timestamp,
+    end_date: pd.Timestamp,
 ) -> str:
     """
     Generate datetime given the random_state, date_format, and start/end dates.
@@ -30,6 +30,10 @@ def generate_datetime(
     :return: generated datetime
     :rtype: str
     """
+    if start_date is None:
+        start_date: pd.Timestamp = pd.Timestamp(1920, 1, 1)
+    if end_date is None:
+        end_date: pd.Timestamp = pd.Timestamp(2049, 12, 31)
     t = rng.random()
     ptime = start_date + t * (end_date - start_date)
 

synthetic_data/distinct_generators/text_generator.py

@@ -9,9 +9,9 @@
 def random_string(
     rng: Generator,
     chars: Optional[List[str]] = None,
-    num_rows: int = 1,
     str_len_min: int = 1,
     str_len_max: int = 256,
+    num_rows: int = 1,
 ) -> np.array:
     """
     Randomly generates an array of strings with length between the min and max values.
@@ -50,9 +50,9 @@ def random_string(
 def random_text(
     rng: Generator,
     chars: Optional[str] = None,
-    num_rows: int = 1,
     str_len_min: int = 256,
     str_len_max: int = 1000,
+    num_rows: int = 1,
 ) -> np.array:
     """
     Randomly generates an array of text with length between the min and max values.
@@ -75,4 +75,4 @@ def random_text(
             f"str_len_min must be > 255. " f"Value provided: {str_len_min}."
         )
 
-    return random_string(rng, chars, num_rows, str_len_min, str_len_max)
+    return random_string(rng, chars, str_len_min, str_len_max, num_rows)

tests/distinct_generators/test_datetime_generator.py

@@ -14,6 +14,17 @@ def setUp(self):
         self.end_date = pd.Timestamp(2023, 1, 1)
         self.date_format_list = ["%Y-%m-%d", "%d-%m-%Y"]
 
+    def test_start_end_date_when_none(self):
+        date_str = date_generator.generate_datetime(
+            self.rng, self.date_format_list[0], start_date=None, end_date=None
+        )
+        try:
+            pd.to_datetime(date_str, format=self.date_format_list[0])
+        except:
+            self.fail(
+                "pd.to_datetime() raised ValueError for start_date, end_date = None"
+            )
+
     def test_generate_datetime_return_type(self):
         date_str = date_generator.generate_datetime(
             self.rng, self.date_format_list[0], self.start_date, self.end_date
@@ -27,7 +38,7 @@ def test_generate_datetime_format(self):
         try:
             pd.to_datetime(date_str, format=self.date_format_list[0])
         except ValueError:
-            self.fail("pd.to_datetime() raised ValueError unexpectedly")
+            self.fail("pd.to_datetime() raised ValueError for custom formatting")
 
     def test_generate_datetime_range(self):
         date_str = date_generator.generate_datetime(
@@ -52,7 +63,7 @@ def test_random_datetimes_default_format_usage(self):
             try:
                 pd.to_datetime(date_str, format="%B %d %Y %H:%M:%S")
             except ValueError:
-                self.fail("pd.to_datetime() raised ValueError unexpectedly")
+                self.fail("pd.to_datetime() raised ValueError for default formatting")
 
     def test_random_datetimes_format_usage(self):
         result = date_generator.random_datetimes(

tests/test_dataset_generator.py

@@ -0,0 +1,85 @@
+import unittest
+from unittest import mock
+
+from numpy.random import PCG64, Generator
+
+from synthetic_data.dataset_generator import generate_dataset_by_class
+
+
+class TestDatasetGenerator(unittest.TestCase):
+    def setUp(self):
+        self.rng = Generator(PCG64(12345))
+        self.dataset_length = 10
+
+    def test_generate_dataset_with_invalid_generator(self):
+        columns_to_gen = [{"generator": "non existent generator"}]
+        with self.assertRaisesRegex(
+            ValueError, "generator: non existent generator is not a valid generator."
+        ):
+            generate_dataset_by_class(
+                self.rng,
+                columns_to_generate=columns_to_gen,
+                dataset_length=self.dataset_length,
+                path=None,
+            )
+
+    def test_generate_dataset_with_none_columns(self):
+        with self.assertRaisesRegex(
+            ValueError,
+            "columns_to_generate is empty and would result in an empty dataframe.",
+        ):
+            generate_dataset_by_class(self.rng, None, self.dataset_length, None)
+
+    def test_generate_custom_datasets(self):
+        columns_to_gen = [
+            {"generator": "integer"},
+            {"generator": "datetime"},
+            {"generator": "text"},
+        ]
+        expected_columns = ["integer", "datetime", "text"]
+        df = generate_dataset_by_class(
+            self.rng,
+            columns_to_generate=columns_to_gen,
+            dataset_length=self.dataset_length,
+            path=None,
+        )
+        self.assertEqual(self.dataset_length, len(df))
+        self.assertListEqual(list(df.columns), expected_columns)
+
+        columns_to_gen = [
+            {"generator": "string"},
+            {"generator": "categorical"},
+            {"generator": "float"},
+        ]
+        expected_columns = ["string", "categorical", "float"]
+        df = generate_dataset_by_class(
+            self.rng,
+            columns_to_generate=columns_to_gen,
+            dataset_length=4,
+            path=None,
+        )
+        self.assertEqual(4, len(df))
+        self.assertListEqual(list(df.columns), expected_columns)
+
+    @mock.patch("synthetic_data.dataset_generator.pd.DataFrame.to_csv")
+    def test_path_to_csv(self, to_csv):
+        """
+        Ensure csv creation is triggered at the appropiate time.
+
+        :param to_csv: mock of Pandas to_csv()
+        :type to_csv: func
+        """
+        columns_to_gen = [
+            {"generator": "integer"},
+            {"generator": "datetime"},
+            {"generator": "text"},
+        ]
+        to_csv.return_value = "assume Pandas to_csv for a dataframe runs correctly"
+        path = "testing_path"
+        generate_dataset_by_class(
+            self.rng,
+            columns_to_generate=columns_to_gen,
+            dataset_length=4,
+            path=path,
+        )
+        to_csv.assert_called_once_with(path, index=False, encoding="utf-8")