# Assertions and Unit Testing ## Python Full documentation - | **Method** | **Description** | | ---------------------------------------------- | ------------------------------------------------------------------------------------------------- | | `assertEqual(first, second)` | Test that *first* and *second* are equal. If the values do not compare equal, the test will fail. | | `assertNotEqual(first, second)` | Test that first and second are not equal. If the values do compare equal, the test will fail. | | `assertAlmostEqual(first, second, delta=none)` | Test that first and second are approximately equal within a positive delta. | | `assertListEqual(first, second)` | Tests that two lists are equal. | | `assertTupleEqual(first, second)` | Tests that two tuples are equal. | | `assertDictEqual(first, second)` | Test that two dictionaries are equal. | | `assertCountEqual(first, second)` | Test that first and second have the same elements in the same number, regardless of their order. | | `assertGreater(first, second)` | Test first > second | | `assertGreaterEqual(first, second)` | Test first >= second | | `assertLess(first, second)` | Test first < second | | `assertLessEqual(first, second)` | Test first <= second | | `assertIs(first, second)` | Test that first and second are the same object. | | `assertIn(member, container)` | Test that member is in container. | | `assertTrue(condition)` | Test that condition is true. | | `assertFalse(condition)` | Test that condition is false. | Why use `assertListEqual()` instead of just `assertEqual()`? Well, they are designed to show the difference between the two values on failure. So students will receive more accurate feedback if you use the proper assertion. Feedback: You can add feedback to assertion failures to alert students what they might have done wrong. To do so, just simply add an additional argument as a string containing the message you want to display. ```python assertEqual(student_output, real_output, "Looks like your code is not outputing the proper value.") ``` Useful Links: * Skipping test and expected failures: ## Java Full documentation - | **Method** | **Description** | | ----------------------------------------------------- | ----------------------------------------------------------- | | `assertEquals(expected, actual)` | Test that two values are equal. | | `assertEquals(expected, actual, delta)` - for doubles | Test that two doubles are equal to within a positive delta. | | `assertArrayEquals(expecteds, actuals)` | Test that two arrays are equal. | | `assertNotNull(object)` | Test that an object isn't null. | | `assertNull(object)` | Test that an object is null. | | `assertNotSame(unexpected, actual)` | Test that two objects do not refer to the same object. | | `assertSame(unexpected, actual)` | Test that two objects refer to the same object. | | `assertTrue(condition)` | Test that a condition is true. | | `assertFalse(condition)` | Test that a condition is false. | Feedback: You can add feedback to assertion failures to alert students what they might have done wrong. To do so, just simply add a string containing the message you want to display as the first argument in the method call. ```python assertEquals("Looks like your code is not outputing the proper value.", realOutput, studentOutput) ``` ## Ruby Ruby calls assertions "matchers" Full documentation -
MatcherDescription
MatcherDescription

expect([]).to be_empty

expect([]).not_to be_empty

# => [].empty?() | passes

# => [].empty?() | fails

expect("a string").to be_an_instance_of(String)

expect(3).to be_a_kind_of(Integer)

expect(3).to be_a_kind_of(Numeric)

expect(3).to be_an_instance_of(Integer) expect(3).not_to be_an_instance_of(Numeric)

# => 3.kind_of?(Numeric) | passes

# => 3.kind_of?(Numeric) | passes

# => 3.instance_of?(Integer) | passes

# => 3.instance_of?(Numeric) | fails

expect(5).to eq(5)

expect(5).not_to eq(3)

expect { print 'foo' }.to output('foo').to_stdoutCheck function output to stdout

expect(5).to satisfy { |n| n > 3 }

expect(5).to satisfy("be greater than 3") { |n| n > 3 }