Add example of using custom assertions (#6)

ggorlen · web-flow · commit fc34f25a804d · 2020-06-12T10:38:15.000-07:00
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1 @@
+__pycache__/
diff --git a/README.md b/README.md
@@ -1,15 +1,52 @@
 # Codewars Test Framework for Python
 
-
-## Example
+### Basic Example
 
 ```python
-from solution import add
 import codewars_test as test
+from solution import add
 
 @test.describe('Example Tests')
 def example_tests():
+
     @test.it('Example Test Case')
     def example_test_case():
         test.assert_equals(add(1, 1), 2, 'Optional Message on Failure')
 ```
+
+### Using Other Assertions
+
+Any function that raises an `AssertionError` can be used instead of `codewars_test` assertions:
+
+```python
+import numpy as np
+import pandas as pd
+import codewars_test as test
+
+@test.describe('Example Tests')
+def test_custom_assertions():
+
+    @test.it('Test something in numpy')
+    def test_numpy_assertion():
+        actual = np.reshape(range(16), [4, 4])
+        expected = np.reshape(range(16, 0, -1), [4, 4])
+        np.testing.assert_equal(expected, actual)
+
+    @test.it('Test something in pandas')
+    def test_pandas_assertion():
+        actual = pd.DataFrame({'foo': [1, 2, 3]})
+        expected = pd.DataFrame({'foo': [1, 42, 3]})
+        pd.testing.assert_frame_equal(expected, actual)
+
+    @test.it('Test something using a custom assertion')
+    def test_custom_assertion():
+        def custom_assert_eq(actual, expected, msg=None):
+            if actual != expected:
+                default_msg = f'`{actual}` did not equal expected `{expected}`'
+                raise AssertionError(default_msg if msg is None else msg)
+
+        actual = 2
+        expected = 1
+        custom_assert_eq(actual, expected)
+```
+
