EventStorming, BDD and sick teachers!

A little workshop about "Exploring behaviour before structure".
@martinschimak and @paulroho -> June 22nd, 2018 -> DDDesign Vienna

Transcript

1. Exploring behaviour before structure. @martinschimak and @paulroho -> June 22nd, 2018 -> Domain-Driven Design Vienna EventStorming, BDD and sick teachers!
2. Do you still remember school? And escaping its „structural model“! :-)
3. Mon Tue Wed Thu Fri 8:00 – 8:50 Mathematics Christiane Lorch Sports Mathias Wils English Stefanie Keller Vocals Reinhold Kneer History Tobias Puth 8:55 – 9:45 Ethics Arnold Unger Sports Mathias Wils History Tobias Puth Vocals Reinhold Kneer French Monique Perron 9:55 – 10:45 French Monique Perron English Stefanie Keller Music Heidi Sokolowski Biology Tatjana Nelles Geography Fabio Baie 10:50 – 11:40 German Julian Wellner French Monique Perron Mathematics Christiane Lorch Music Heidi Sokolowski German Julian Wellner 11:55 – 12:45 Music Heidi Sokolowski German Julian Wellner French Monique Perron English Stefanie Keller German Julian Wellner 12:50 – 13:40 Music Heidi Sokolowski - Ethics Arnold Unger Mathematics Christiane Lorch Mathematics Christiane Lorch 5c - 2017/18 International Music Highschool 1090 Vienna
4. Group brainstorming: How do we call the structural elements we find in a school‘s timetable?
5. Structural models don‘t convey what HAPPENS going through time.
6. Events? Something happened! Teacher absence reported
7. Quick group brainstorming: who is affected by such an event? Teacher absence reported
8. More brainstorming leads to more events! Teacher absence reported Substitute informed Lesson canceled Parents informed
9. Policies… when decisions need to be made! Teacher absence reported Substitute informed Lesson canceled Parents informed Substitutes decision
10. Substitute informed Lesson canceled Parents informed Substitutes decision Commands... when decisions need to be executed! Cancel lesson Inform substitute Teacher absence reported
11. Group EventStorming: What would need to happen when it happens? Teacher absence reported
12. Quick question: what triggers you to add a new sticky or remove one?
13. Describing software behaviour with Gherkin GIVEN a state to be assumed WHEN we trigger a change THEN we will observe an expected result Verify Setup Execute
14. A policy. And a possible rule detailing it. - Preferredly, teachers that teach a class in another subject are chosen to substitute absent teachers. - … Substitutes decision
15. Gherkins to describe rules detailing a policy GIVEN a set of events happened WHEN another event happens THEN a command will follow – or not Command Decision rules Domain event Domain event Domain event
16. Group work: When looking at your policies, what would be specific scenarios (expressed as examples) illustrating one of the decision rules?
17. FEATURE: Substitutes Decision. Policy to decide who shall substitute an absent teacher. SCENARIO: Preferredly, teachers that teach a class in another subject are chosen to substitute absent teachers. GIVEN the following teachers are assigned to teach 5c: | Teacher | Subject | | Christiane Lorch | Mathematics | | Julian Wellner | German | AND 5c has a mathematics lesson scheduled on Wednesday 10:50 to 11:40 AND Julian Wellner is reserved as substitute on Wednesday 10:50 to 11:40 WHEN Christiane Lorch reports her absence THEN Julian Wellner shall substitute Christiane Lorch on Wednesday 10:50 to 11:40 Substitute lesson Substitutes decision Teacher absence reported Teacher assigned to class Lesson scheduled for class Teacher assigned to teach class Teacher reserved as substitute
18. Gherkins to describe rules when executing a command GIVEN a set of events happened WHEN a command executes THEN another event will happen – or not Command Consistency rules Domain event Domain event Domain event
19. FEATURE: Substitute lesson. A teacher shall be assigned to substitute for a specific lesson. SCENARIO: A substitute teacher must not be assigned to conflicting duties. GIVEN Julian Wellner is assigned to substitute Arnold Unger on Monday 08:00 to 08:50 WHEN Julian Wellner shall substitute Christiane Lorch on Monday 08:00 to 08:50 THEN Julian Wellner will not be assigned to substitute Christiane Lorch on Monday 08:00 to 08:50 Substitute lesson Teacher assigned to substitute Teacher assigned to substitute
20. Gherkins to describe rules for creating a report GIVEN a set of events happened WHEN another event happens THEN a report will reflect the expected state Projection rules Domain event Domain event Report
21. FEATURE: Time table. Report reflecting the actual lessons scheduled for a specific class. SCENARIO: A substitution is reflected in the time table for the affected class. GIVEN Christiane Lorch is assigned to teach mathematics in 5c AND 5c has a mathematics lesson scheduled on Wednesday 10:50 to 11:40 WHEN Julian Wellner substitutes Christiane Lorch on Wednesday 10:50 to 11:40 THEN 5c time table will reflect Julian Wellner as substitute on Wednesday 10:50 to 11:40 AND 5c time table will reflect a german lesson scheduled on Wednesday 10:50 to 11:40 Teacher assigned to substitute Time table Lesson scheduled for class Teacher assigned to teach class
22. Mon Tue Wed Thu Fri 8:00 – 8:50 Mathematics Christiane Lorch Sports Mathias Wils English Stefanie Keller Vocals Reinhold Kneer History Tobias Puth 8:55 – 9:45 Ethics Arnold Unger Sports Mathias Wils History Tobias Puth Vocals Reinhold Kneer French Monique Perron 9:55 – 10:45 French Monique Perron English Stefanie Keller Music Heidi Sokolowski Biology Tatjana Nelles Geography Fabio Baie 10:50 – 11:40 German Julian Wellner French Monique Perron German Julian Wellner Music Heidi Sokolowski German Julian Wellner 11:55 – 12:45 Music Heidi Sokolowski German Julian Wellner French Monique Perron English Stefanie Keller German Julian Wellner 12:50 – 13:40 Music Heidi Sokolowski - Ethics Arnold Unger Mathematics Christiane Lorch Mathematics Christiane Lorch 5c - 2017/18 International Music Highschool 1090 Vienna
23. Group discussion: What do you think about relating EventStorming results to Gherkin example scenarios?