![Do you smell something?
<code />
[Fact]
public void Given_regular_item_SellIn_and_Quality_lower()
{
IList<Item> items =
new List<Item> { new Item { Name = "Regular Item", SellIn = 15, Quality = 25 } };
Program app = new Program() { Items = items };
app.UpdateQuality();
Assert.Equal(14, items[0].SellIn);
Assert.Equal(24, items[0].Quality);
}
[Fact]
public void Given_regular_item_past_SellIn_Then_Quality_degrades_twice_as_fast()
{
IList<Item> items =
new List<Item> { new Item { Name = "Regular Item", SellIn = 0, Quality = 25 } };
Program app = new Program() { Items = items };
app.UpdateQuality();
Assert.Equal(23, item.Quality);
}
Duplicated Code!
How can we fix this duplication code smell](https://image.slidesharecdn.com/34practicingredgreenrefactor-230115084134-b1a51703/85/Practicing-Red-Green-Refactor-17-320.jpg)
![What other code smells are there?
<code />
Magic Strings!
public void UpdateQuality()
{
for (var i = 0; i < Items.Count; i++)
{
if (Items[i].Name != "Aged Brie" && Items[i].Name != "Backstage passes to a TAFKAL80ETC concert")
{
if (Items[i].Quality > 0)
{
if (Items[i].Name != "Sulfuras, Hand of Ragnaros")
{
Items[i].Quality = Items[i].Quality - 1;
}
}
}
else
{
…
}
}
}](https://image.slidesharecdn.com/34practicingredgreenrefactor-230115084134-b1a51703/85/Practicing-Red-Green-Refactor-24-320.jpg)
![What other code smells are there?
<code />
Magic Numbers!
public void UpdateQuality()
{
for (var i = 0; i < Items.Count; i++)
{
if (Items[i].Name != "Aged Brie" && Items[i].Name != "Backstage passes to a TAFKAL80ETC concert")
{
…
}
else
{
if (Items[i].Quality < 50)
{
Items[i].Quality = Items[i].Quality + 1;
…
}
}
}](https://image.slidesharecdn.com/34practicingredgreenrefactor-230115084134-b1a51703/85/Practicing-Red-Green-Refactor-25-320.jpg)
Practicing Red, Green, Refactor!
- 1. Practicing Red, Green, Refactor! Held by, Ahmed Helmy
- 3. Exercise in Self Organization Hello everyone! Line up and organize yourself into a single file line per programming language from the most experience to the least experience in coding When you are done let me know.
- 4. Development Team When you wake up in the morning and you come in to work, you say, “what is the focus – are we trying to ship or are we trying to write code?” The answer is we are trying to ship. You’re not trying to write code, you’re trying not to write code. Former Microsoft Program Manager, Chris Peters
- 5. What is eXtreme Programming? XP aims to produce higher quality software using appropriate engineering practices Agile Software Development Methodology Lightweight Efficient Low-risk
- 7. XP Practices • Fine-scale feedback • Pair programming • The Planning Game • Testing • On-site customer • Continuous process • Continuous integration • Refactoring • Small releases • Shared understanding • Coding standards • Collective ownership • Simple design • Metaphor • Programmer welfare • 40 hour week
- 8. XP Practices
- 9. Let’s Discuss What is testing? And what are the testing types?
- 11. Baby-steps Kata •Pair up •Design a system that generates an even number. •Ends in 2. •Greater than 9. •Less than 100. •Adding both digits should result in 6.
- 12. Pair Programming • Two people write code together on one machine https://martinfowler.com/articles/on-pair-programming.html
- 13. FizzBuzz Kata
- 14. BREAK!
- 15. GildedRose Kata • Clone GildedRose Kata Repository • C#: https://github.com/NotMyself/GildedRose • Other: https://github.com/emilybache/GildedRose-Refactoring-Kata • Gathering Requirements (readme file) • Add tests based on requirements • Add tests based on code coverage report • Refactoring • Adding new behavior • Extract class • Simplify arithmetic • Extract constant strings • Simplify Booleans • Extract constant numbers • Group related logic • Extract methods • Rename
- 16. GildedRose Kata • Add tests based on requirements
- 17. Do you smell something? <code /> [Fact] public void Given_regular_item_SellIn_and_Quality_lower() { IList<Item> items = new List<Item> { new Item { Name = "Regular Item", SellIn = 15, Quality = 25 } }; Program app = new Program() { Items = items }; app.UpdateQuality(); Assert.Equal(14, items[0].SellIn); Assert.Equal(24, items[0].Quality); } [Fact] public void Given_regular_item_past_SellIn_Then_Quality_degrades_twice_as_fast() { IList<Item> items = new List<Item> { new Item { Name = "Regular Item", SellIn = 0, Quality = 25 } }; Program app = new Program() { Items = items }; app.UpdateQuality(); Assert.Equal(23, item.Quality); } Duplicated Code! How can we fix this duplication code smell
- 18. GildedRose Kata • Add tests based on requirements
- 19. Let’s Discuss Are we done yet? Can we now safely add new functionality?
- 20. Test Coverage • Measure how much of your code base is exercised by your unit test suite • A code base with less than 100% coverage does not necessarily mean that the code lacks quality. • A code base with 100% coverage ensures only that its quality is as good as the tests that exercise it. • A better measure of code coverage is whether the right code is covered by tests! • This examination will always reveal one of two outcomes • You are missing a test • The code is unneeded and should be deleted (NOT COMMENTED)
- 21. GildedRose Kata • Add tests based on requirements • Add tests based on code coverage report
- 23. What other code smells are there? <code /> Large Class! More responsibilities! Program.cs namespace GildedRose.Console { public class Program { ... } public class Item { public string Name { get; set; } public int SellIn { get; set; } public int Quality { get; set; } } } Program.cs namespace GildedRose.Console { public class Program { … public void UpdateQuality() { … } } public class Item { … } }
- 24. What other code smells are there? <code /> Magic Strings! public void UpdateQuality() { for (var i = 0; i < Items.Count; i++) { if (Items[i].Name != "Aged Brie" && Items[i].Name != "Backstage passes to a TAFKAL80ETC concert") { if (Items[i].Quality > 0) { if (Items[i].Name != "Sulfuras, Hand of Ragnaros") { Items[i].Quality = Items[i].Quality - 1; } } } else { … } } }
- 25. What other code smells are there? <code /> Magic Numbers! public void UpdateQuality() { for (var i = 0; i < Items.Count; i++) { if (Items[i].Name != "Aged Brie" && Items[i].Name != "Backstage passes to a TAFKAL80ETC concert") { … } else { if (Items[i].Quality < 50) { Items[i].Quality = Items[i].Quality + 1; … } } }
- 26. What other code smells are there? <code /> Nested Conditionals! Long Function! public void UpdateQuality() { for (var i = 0; i < Items.Count; i++) { if (item.Name != "Aged Brie" && item.Name != "Backstage passes to a TAFKAL80ETC concert") { if (item.Quality > 0) { if (item.Name != "Sulfuras, Hand of Ragnaros") { item.Quality = item.Quality - 1; } } } else { … } } }
- 27. Still Complex!
- 28. Code Smells and Anti-Code Smells Code Smells Anti-Code Smells Mysterious name Clear naming Duplicated code Extract function Long method Extract function Nested conditionals Polymorphism Speculative generality Change function declaration Large class Extract class Comments Extract function
- 29. Add New Behavior