1. TDD Katas in Magento 2
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3. Code Kata
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4. Code Kata?
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5. We practice our craft.
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6. We train like
athletes do.
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7. What do we train in a code kata?
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8. The Mind
→ The 3 phases of TDD
→ Working in small units
→ Recognizing patterns
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9. The Body
→ Keyboard shortcuts
→ Efficient grouping of actions
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10. Framework Knowledge
→ Memorizing framework sections
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11. Katas are usually done
multiple times
over a
period of time.
E.g. once per day over 1 week,
once per week over 3 months,
...
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12. Time Limit:
15 - 30 minutes
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13. Today is just a
Demo
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14. An impression how
TDD in Magento
can look.
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15. To inspire you to
start doing katas
as soon as you are back!
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16. Today's Kata:
Magento 2 Total Model
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17. Total Models
A flexible system to calculate cart and cart
item prices and adjustments.
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18. <!-- File: etc/sales.xml -->
<section name="quote">
<group name="totals">
<item name="subtotal" sort_order="100"
instance="MagentoQuoteModelQuoteAddressTotalSubtotal"/>
<item name="tax_subtotal" sort_order="200"
instance="MagentoTaxModelSalesTotalQuoteSubtotal"/>
<item name="shipping" sort_order="250"
instance="MagentoQuoteModelQuoteAddressTotalShipping"/>
<item name="discount" sort_order="400"
instance="MagentoSalesRuleModelQuoteDiscount"/>
<item name="tax" sort_order="450"
instance="MagentoTaxModelSalesTotalQuoteTax"/>
<item name="grand_total" sort_order="550"
instance="MagentoQuoteModelQuoteAddressTotalGrand" />
</group>
</section>
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19. Processed in order
→ First comes subtotal
Sets quote item prices & subtotal
→ Then all the others
shipping, discount, tax, ...
→ Last comes grand_total
Sums up all other total models
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20. Each one adds it's value on
ModelQuoteAddressTotal
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21. The Kata Example code is
missing a custom total model.
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22. Training Module: Example_GiftItem
When a customer adds a product from the
sample data "Bags" attribute set,
to the cart, also add a free water bottle.
https://github.com/Vinai/module-example-giftitem
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23. Training Module: Example_GiftItem
The GiftItem total model is responsible
for setting the price of gift items to zero
and adjusting the subtotal.
https://github.com/Vinai/module-example-giftitem
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24. What does this kata teach?
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25. (1/2) Generic skills:
→ TDD Red-Green-Refactor process
→ Working with test doubles
→ Separating pure functions
from functions with side effects
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26. (2/2) Magento skills:
→ Test driving Magento development
→ The totals architecture
→ Dealing with Law of Demeter violations
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27. Tomorrow
How you can get started:
# Create module dir
mkdir -p app/code/Example && cd app/code/Example
# Clone repo
git clone https://github.com/Vinai/module-example-giftitem.git GiftItem
cd GiftItem
# Check out git tag
git checkout beginning-of-kata
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28. Kata Task:
Use TDD to create the GiftItem total model
ModelTotalsGiftItemAddressTotal
Implement the collect() method.
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29. Target behavior: collect()
→ Subtract gift item row totals sum and
base row totals sum from the subtotal
→ Set calculation_price
and base_calculation_price
of every gift item to zero
→ Call calcRowTotal on each gift
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30. Enjoy the session and
feel those reflexes
get sharper!
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