great-assertions 0.0.59

Lightweight assertions inspired by the great-expectations library

This library is inspired by the Great Expectations library. The library has made the various expectations found in Great Expectations available when using the inbuilt python unittest assertions.

Install

pip install great-assertions

Code example Pandas

from great_assertions import GreatAssertions
import pandas as pd

class GreatAssertionTests(GreatAssertions):
    def test_expect_table_row_count_to_equal(self):
        df = pd.DataFrame({"col_1": [100, 200, 300], "col_2": [10, 20, 30]})
        self.expect_table_row_count_to_equal(df, 3)

Code example PySpark

from great_assertions import GreatAssertions
from pyspark.sql import SparkSession

class GreatAssertionTests(GreatAssertions):

    def setUp(self):
        self.spark = SparkSession.builder.getOrCreate()

    def test_expect_table_row_count_to_equal(self):
        df = self.spark.createDataFrame(
            [
                {"col_1": 100, "col_2": 10},
                {"col_1": 200, "col_2": 20},
                {"col_1": 300, "col_2": 30},
            ]
        )
        self.expect_table_row_count_to_equal(df, 3)

List of available assertions

	Pandas	PySpark
expect_table_row_count_to_equal	white_check_mark::	white_check_mark::
expect_table_row_count_to_be_greater_than	white_check_mark::	white_check_mark::
expect_table_row_count_to_be_less_than	white_check_mark::	white_check_mark::
expect_table_has_no_duplicate_rows	white_check_mark::	white_check_mark::
expect_column_value_to_equal	white_check_mark::	white_check_mark::
expect_column_values_to_be_between	white_check_mark::	white_check_mark::
expect_column_values_to_match_regex	white_check_mark::	white_check_mark::
expect_column_values_to_be_in_set	white_check_mark::	white_check_mark::
expect_column_values_to_be_of_type	white_check_mark::	white_check_mark::
expect_table_columns_to_match_ordered_list	white_check_mark::	white_check_mark::
expect_table_columns_to_match_set	white_check_mark::	white_check_mark::
expect_date_range_to_be_more_than	white_check_mark::	white_check_mark::
expect_date_range_to_be_less_than	white_check_mark::	white_check_mark::
expect_date_range_to_be_between	white_check_mark::	white_check_mark::
expect_column_mean_to_be_between	white_check_mark::	white_check_mark::
expect_column_value_counts_percent_to_be_between	white_check_mark::	white_check_mark::
expect_frame_equal	white_check_mark::	white_check_mark::
expect_column_has_no_duplicate_rows	white_check_mark::	white_check_mark::

Assertion Descriptions

For a description of the assertions see Assertion Definitions

Running the tests

Executing the tests still require unittest, the following options have been tested with the examples provided.

Option 1

import unittest
suite = unittest.TestLoader().loadTestsFromTestCase(GreatAssertionTests)
runner = unittest.TextTestRunner(verbosity=2)
runner.run(suite)

Options 2

if __name__ == '__main__':
    unittest.main()

Pie Charts and Tables

For a more visual representation of the results, when using in Databricks or Jupyter Notebooks. The results can be outputed as tables or pie-chart.

import unittest
from great_assertions import GreatAssertionResult, GreatAssertions

class DisplayTest(GreatAssertions):
    def test_pass1(self):
        assert True is True

    def test_fail(self):
        assert "Hello" == "World"

suite = unittest.TestLoader().loadTestsFromTestCase(DisplayTest)
test_runner = unittest.runner.TextTestRunner(resultclass = GreatAssertionResult)
result = test_runner.run(suite)

result.to_barh() #Also available: result.to_pie()

result.to_results_table()

result.to_full_results_table()

Runnng with XML-Runner

To run with xml-runner, there is no difference to how it’s currently used. However you will not be able to get method like to_results_table as these use a different resultclass

import xmlrunner
suite = unittest.TestLoader().loadTestsFromTestCase(DisplayTest)
test_runner = xmlrunner.XMLRunner(output="test-results")
test_runner.run(suite)

Notes

If you get an arrows function warning when running in Databricks, this will happen becuase a toPandas() method is being used for many of the assertions. The plan is to remove pandas conversion for pure PySpark code. If this is an issue please raise an issue so this method can be prioritised. For now its advisable to makre sure the datasets are not too big, which cause the driver to crash.

Development

To create a development environment, create a virtualenv and make a development installation

virtualenv ve
source ve/bin/activate

To run tests, just use pytest

(ve) pytest