docs(lecture): interfaces between components

04-lecture/README.md

@@ -0,0 +1,167 @@
+# 04 - Design of Interfaces between components. Testing
+
+## Content
+
+- Testing
+- Interfaces between components
+- FAQs
+- QMP
+- Activities
+
+## Testing
+
+Don't you taste your _guiso_ when you're cooking?
+
+### Why do we test?
+
+- Validate correct behavior
+- Find bugs
+
+> A good test **finds** bugs
+
+### Integration Grade
+
+- Unit
+- Integration
+  - Low
+  - High
+  - End to End
+
+### Automation Grade
+
+- Manual
+- Semi-automatic
+- Automatic
+
+### Styles
+
+- Unit or Assert per test
+- Spec or _behavoural_
+- Etc...
+
+### Quality
+
+- Maintainability
+- Strcuture
+- Fixture
+- Independecy
+
+### Impostor
+
+- Mocks/stubs/etc
+- Respects interface
+- Fills _voids_
+- Avoids reliance upon real implementation
+- Verifies behavior
+
+### FAQs
+
+_Mock_ vs _Stub_. The difference relies on what can you do with both of them.
+
+Example
+
+```java
+class Company{
+    String name;
+    Integer numberOfEmployees;
+
+    public List<Taxes> taxesToPay(){
+        return getTaxCategory().getTaxes()
+    }
+
+    public TaxCategory categorize();{
+        // Method stub
+        // TODO: complete this
+        return TaxCategory.MEDIUM;
+    }
+}
+
+class TaxCategory{
+    LOW, MEDIUM, HIGH;
+}
+```
+
+Another example, extracting method to another class...
+
+```java
+interface TaxRegulator{
+    TaxCategory categorize();
+}
+
+// For test, and only Test
+public class TaxRegulatorMock implements TaxRegulator{
+    @Override
+    public TaxCategory categorize(){
+        return TaxCategory.MEDIUM;
+    }
+}
+```
+
+### Mockito
+
+Tasty mocking framework for unit tests in Java
+
+<https://site.mockito.org/>
+
+## Interfaces between components
+
+How to connect things and not die trying to.
+
+- Way of connecting components
+- Allows making and agreement
+- Generates abstraction
+- Allows abstraction of internal details
+- Allows interchange
+
+### Outgoing
+
+How I want to speak to the world
+
+```java
+class Promotion{
+    String title;
+    String promotionalText;
+    File image;
+}
+
+class User{
+    String name;
+    String mail;
+}
+```
+
+```java
+class Store{
+    PromotionCampaing promotion;
+
+    void promote(Promotion promo, List<User> users){
+        users.forEach( user -> promotion.sendPromotion(promo, user));
+    }
+}
+```
+
+### Incoming Interface
+
+How I want the World speaks to me (or I want the world to talk to me)
+
+```java
+class MailSender{
+    void sendMail(String subject, String address, String body, List<File> attachments)
+}
+```
+
+### Adapter
+
+```java
+class PromotionViaMail implements PromotionCampaing{
+    @Override
+    public void sendPromotion(Promotion promo, User user){
+        new MailSender().sendMail(
+            promo.getTitle(),
+            user.getMail(),
+            promo.getPromotionalTest(user.getName()),
+            Arrays.asList(promo.getImage())
+        );
+    }
+}
+```