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Fix my TDD
Patterns for efficient Tests
Fix my TDD Patterns for efficient Tests TDD in a Nutshell Test - - PowerPoint PPT Presentation
Fix my TDD Patterns for efficient Tests TDD in a Nutshell Test - - PowerPoint PPT Presentation
Fix my TDD Patterns for efficient Tests TDD in a Nutshell Test Christian Fischer Refactoring Implementation Simple, but not easy Christian Fischer Password Validator Kata boolean validate(String password) A password it valid, when it has
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Christian Fischer
TDD in a Nutshell
Test Implementation Refactoring
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Christian Fischer
Simple, but not easy
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Christian Fischer
Password Validator Kata
boolean validate(String password) A password it valid, when it has
- at least 6 characters
- at least one upper case letter
- at least one lower case letter
- at least one special character
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Christian Fischer
The Test List
Valid password „aBc_de -> true Less than minimum characters „aBc_de“ -> false No upper case „ab_cde“ -> false No lower case „ABC_DE“ -> false No special character „aBcxde“ -> false
1
Analyse the problem
2
find simple examples for each equivalence class
3
add to list any time, but don‘t interrrupt cycle
from Kent Beck
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Christian Fischer
Test Storming
- Swarm Intelligence
- Time boxing
- Integration in Refinement
and Planning or 3-Amigo-Session
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Christian Fischer
Test Path
- from simple to complex
- start with happy path
- use git to rewind
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Christian Fischer
ZOMBIES
Simple Scenarios Simple Solutions Zero One Many Boundaries Behavior Interfaces Exercise Exceptions
from James Grenning
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Christian Fischer
Transformation Priority Premise
{}
- -> nil
nil
- -> constant
constant
- -> constant+
constant
- -> scalar
statement
- -> statements
unconditional --> if scalar
- -> array
array
- -> container
statement
- -> recursion
if
- -> while
expression
- -> function
variable
- -> assignment
simple complex from Robert C. Martin
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Christian Fischer
TDD Tip #1
Always start with an ordered test list.
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Christian Fischer
QueryParserTest
Query Parser Kata
„guitar“ -> [guitar] “red electric guitar“ -> [red, electric, guitar] „red guitar with gigbag“ -> [red,guitar,gigback] „red guitar and gigbag“ -> [red,guitar,gigback]
QueryParser
+ parse(String query): String[]
- removeStopwords(String[] words) : String[]
„red guitar with 7 gigbag“ -> [red,guitar,gigback]
- removeNumbers(String[] words) : String[]
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Christian Fischer
QueryFilter QueryFilterTest QueryParserTest
Query Parser Kata
„guitar“ -> [guitar] “red electric guitar“ -> [red, electric, guitar] [red,guitar,with,gigback]-> [red,guitar,gigback] [red,guitar,and,gigback] -> [red,guitar,gigback]
QueryParser
+ parse(query: String): String []
- removeStopwords(words: String[]) : String[]
[red,guitar,7,gigback] -> [red,guitar,gigback]
- removeNumbers(words: String[]) : String[
+ filter(words: String[]): String[] + QueryParser(filter: QueryFilter)
- setUpMocks / MockInteractionTest
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Christian Fischer
QueryFilter QueryFilterTest QueryParserTest
Query Parser Kata
„guitar“ -> [guitar] “red electric guitar“ -> [red, electric, guitar] [red,guitar,with,gigback]-> [red,guitar,gigback] [red,guitar,and,gigback] -> [red,guitar,gigback]
QueryParser
+ parse(query: String)
- removeStopwords(words: String[]) : Stri
[red,guitar,7,gigback] -> [red,guitar,gigback]
- removeNumbers(words: String[]) : String[
+ filter(words: String[]): String[] + QueryParser(filter: QueryParser)
- setUpMocks
„Guitar“ -> [guitar]
- toLowerCase(word: String) : String
- toSingular(word: String) : String
“guitars“ -> [guitar]
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Christian Fischer
QueryFilter QueryFilterTest QueryParserTest
Query Parser Kata
„guitar“ -> [guitar] “red electric guitar“ -> [red, electric, guitar] [red,guitar,with,gigback]-> [red,guitar,gigback] [red,guitar,and,gigback] -> [red,guitar,gigback]
QueryParser
+ parse(query: String)
- removeStopwords(words: String[]) : Stri
[red,guitar,7,gigback] -> [red,guitar,gigback]
- removeNumbers(words: String[]) : String[
+ filter(words: String[]): String[] + QueryParser(filter: QueryFilter, normalizer: QueryNormalizer)
- setUpMocks / MockInteractionTest
QueryNormalizerTest
„Guitar“ -> „guitar“ „guitars“ -> „guitar“
QueryNormalizer
+ normalize(word: String): String
- toLowerCase(word: String) : String
- toSingular(word: String) : String
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Christian Fischer
Strong Coupling
Parser Module
QueryParser QueryFilter QueryNormalizer QueryParserTest
Parser Tests
QueryFilterTest QueryNormalizerTest
public Class package private Class
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Christian Fischer
Loose Coupling
Parser Module
QueryParser QueryFilter QueryNormalizer QueryParserTest
Parser Tests
QueryFilterTest QueryNormalizerTest
public Class package private Class
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Christian Fischer
Leaky Refactoring
Refactoring: Split name into two fields.
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Christian Fischer
TDD Tip #2
Develop your Tests against the Module API.
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Christian Fischer
In a galaxy (not so) far far away
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Christian Fischer
Problems
- Fixating Design & Framework
- Testing implementation, not Behaviour
- Speculating about 3rd party behaviour
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Christian Fischer
The golden Rule
ONLY MOCK TYPES THAT YOU OWN
from „Growing Object Oriented Design, guided by Tests [Steve Freeman, Nat Pryce]
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Christian Fischer
Weak Unit Tests
Does the Endpoint has the corrrect Path & Method? Does the Deserialization works as expected? Does the Serialization works as expected?
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Christian Fischer
Two Component Types …
- Input/Output
- Side Effects
- Nonfunctional driven
- deterministic
- Business Logic
- feature driven
T echnical L ogical
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Christian Fischer
Unit Test L ogical
▪ Repeatable ▪ Consistent ▪ In Memory ▪ Fast ▪ Single Concern
Unit Test is ...
from Roy Osherove: The art of Unit Testing
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Christian Fischer
Integration Test T echnical
▪ Use system dependent variables ▪ Create object with little Control (e.g. Threads, etc.) ▪ Reach out to external systems ▪ Test several components
Integration Test may ...
from Roy Osherove: The art of Unit Testing
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Christian Fischer
Design with CRC Cards
Component Reponsibility Collaborators should…
- ……
- ……
- ……
calls…
- ……
- ……
- ……
from Kent Beck
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Christian Fischer
TDD Tip #3
Write Adapters for Integration Code and mock these.
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Christian Fischer
5 Rules for efficient and effective TDD
1 Develop your Tests against the Module API. 2 Test the Behaviour, not the Implementation. 4 Use Integration Tests for I/O-Components. 3 Don‘t mock external libraries, use Adapters. 5 Make a Test Plan.
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Christian Fischer no Multi- Tasking Protection from Overengineering Complexity Partitioning no Fear
- f Change
zero Debug Time Testable Design
TDD Benefits
TDD
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