Explore writing unit tests for Java applications using JUnit, delve into JUnit organization, assertions, quality practices, design relevance, refactoring, and using mock objects for dependencies.

Pragmatic Unit Testing in Java 8 with Junit by The Pragmatic Programmer.png

junit.tar.gz

java

test2

test4 - Our first passing test

test6

test14

test16-branch-persistence

AssertTest-13

test15

test15-profile

test15-ProfilePoolTest

test16-BearingTest

test16-RectangleTest

test16-SparseTest

test16-TransmissionTest

test16-ProfileTest

test20m-ProfileTest

test21-Profile

big1-Profile

big1-MatchSet

big4-MatchSetTest

big4-MatchSet

big6

mock-2-AddressRetrieverTest

mock-4-AddressRetrieverTest

mock-5-AddressRetrieverTest

test1-SearchTest

test3-SearchTest

tdd-1-ProfileTest.java 

tdd-2-ProfileTest.java

tdd-3-ProfileTest.java

tdd-4-Profile.java

tdd-5-ProfileTest.java

tdd-9-ProfileTest.java

tdd-10-ProfileTest.java

tdd-10-AnswerTest.java

tdd-11-ProfileTest.java

tdd-12-ProfileTest.java

tdd-14-ProfileTest.java

tdd-15-ProfileTest.java

thread-2-ProfileMatcherTest

thread-3-ProfileMatcherTest

thread-4-ProfileMatcherTest

test16-branch-persistence-redesign-QCTest

AssertHamcrest-13

test16-branch-persistence-redesign-StatCompilerTest

test16-ProfilePoolTest

test15-ProfilePoolTest-copy 16

test3-SearchTest-ContainsMatches

tdd-11-ProfileTest.java-Supporting Multiple Answers

thread-2-ProfileMatcherTest-Testing Multithreaded Code

test2-Our First passing test

test4 - AAA your way to a test

test2-final-intro-junit

In this course, you will learn how to write a unit test for Java applications using JUnit. You'll start by covering unit-testing foundations, which provide you with a starter set of information about writing basic tests in JUnit. You’ll learn about JUnit organization and assertions, and you’ll pick up a few core quality practices for unit testing such as the Right BICEP and the CORRECT way. 

Towards the end, the bigger design picture focuses on the relevance of design to unit testing and vice versa. You’ll refactor your tests, and you’ll learn how to use mock objects to deal with trouble-some dependencies.

Pragmatic Unit Testing in Java 8 with JUnit

## Distractions
Although we want to turn off logging when tests run, the code to do so is a distraction to understanding the essence of any test. Though we should always close streams, doing so is also a distraction.

## Using `@After` and `@Before` methods
To remedy this issue, let’s move the bits of clutter to `@Before` and `@After` methods. To allow both tests to take advantage of the `stream.close()` in the `@After` method, change the second test to reference the stream field instead of the local variable named `inputStream`.

We should also look at the line that reads:


We also ponder the line that reads:
```java
assertFalse(search.errored()); 
```
The above assertion isn’t an irrelevant detail since it’s a valid assertion. We might consider it as a second postcondition of running a search, but it hints at something deeper. Namely, it prompts us to ask where is the test case that generates a true value for `search.errored()`? Delete the assertion and make a note to add a third (and maybe also a fourth) test before committing.

## Challenge
Here are the decluttering changes:

* Add the following `@Before` in the code (lines 15-18). 
```
@Before
public void turnOffLogging() {
   Search.LOGGER.setLevel(Level.OFF);
}
```
* Add the following `@After` in the code (lines 20-23).
```
@After
public void closeResources() throws IOException {
   stream.close();
}
```

# Distractions
Although we want to turn off logging when tests run, the code to do so is a distraction to understanding the essence of any test. Though we should always close streams, doing so is also a distraction.

# Using `@After` and `@Before` methods
To remedy this issue, let’s move the bits of clutter to `@Before` and `@After` methods. To allow both tests to take advantage of the `stream.close()` in the `@After` method, change the second test to reference the stream field instead of the local variable named `inputStream`.

We should also look at the line that reads:


We also ponder the line that reads:
```java
assertFalse(search.errored()); 
```
The above assertion isn’t an irrelevant detail since it’s a valid assertion. We might consider it as a second postcondition of running a search, but it hints at something deeper. Namely, it prompts us to ask where is the test case that generates a true value for `search.errored()`? Delete the assertion and make a note to add a third (and maybe also a fourth) test before committing.

# Challenge
Here are the decluttering changes:

* Add the following `@Before` in the code (lines 15-18). 
```
@Before
public void turnOffLogging() {
   Search.LOGGER.setLevel(Level.OFF);
}
```
* Add the following `@After` in the code (lines 20-23).
```
@After
public void closeResources() throws IOException {
   stream.close();
}
```

Learn how to remove irrelevant details by using the @After and @Before helper methods.

Test Smell: Irrelevant Details

Before We Begin

JUnit Test Foundations

Digging Deeper into JUnit Assertions

Organizing Your Tests

Mastering Manic Mnemonics!

What to Test: The Right-BICEP

Boundary Conditions: The CORRECT Way

The Bigger Design Picture

Bigger Design Issues

Using Mock Objects

Refactoring Tests

The Bigger Unit-Testing Picture

Testing Some Tough Stuff

Testing on a Project

Wrapping Up

Appendix - Setting up JUnit

Test Smell: Irrelevant Details

Distractions

Using `@After` and `@Before` methods

Test Smell: Irrelevant Details

Distractions

Using @After and @Before methods

Using `@After` and `@Before` methods