The deck contains a few ideas how to improve iOS apps code quality using continuous inspection and unit testing

1. How to improve
Code Quality?
iOS apps
RECOMMENDATIONS

2. Code Quality
Continuous
Inspection
Unit
Testing
2

3. Sonar covers the 7 axes of code quality
SONAR an open source web application
to manage code quality

4. Key metrics
 Potential bugs
 Potential performance problems
 Potential security issues
 Duplicates
 Unused Code
 Code Complexity
 Technical debt
 Сoverage

5. Community Plugin
5
FREE
No support
Might not support Xcode 8
https://github.com/Backelite/sonar-
objective-c

6. Official Plugin
6
€ 5,000 per year
Support included
Frequent new releases
http://www.sonarsource.com/products/plugi
ns/languages/objective-c/

7. Comparison
community plugin official plugin
price Free € 5,000 per year
support no included
metrics •Complexity: uses Lizard
•Documentation: blank comments, comment
lines, %
•Duplication: blocks, linkes, %
•Issues: Uses OCLint: 63 rules, and Faux Pas: 102
rules
•Size
•Test: Uses xctool, will probably switch to
xcodebuild + xcpretty soon
•Code coverage: With gcovr for project before
Xcode 7, otherwise slather
more details: https://github.com/octo-
technology/sonar-objective-
c/wiki/Features, https://github.com/Backelite/son
ar-objective-c
200+ rules: details
supported
systems
•Given that there is no official support, POC is
required to check it whether it works with XCode
8
•0.4.x releases for SonarQube >= 4.3 (4.x and 5.x)
•latest release was in 01/2015
•no information about XCode
supported
•all Sonar versions are
supported

8. Recommendations
Configure Objective C and Swift
community plugins
Set up daily scans
Configure daily emails
to the dev team
Analyze results
•Define areas for improvements:
•Security, unused code, code
duplicates, potential performance
issues
•Reduce code complexity
•Fix existing critical and major issues
Fix new issues
8
If community plugins don’t work - buy an official plugin

9. Metrics and KPIs to track
Track Issues provided by plugin:
◦ fix blockers and majors
◦ set an acceptable threshold for minor and info
Track the next metrics:
◦ technical debt (calculated by the tool)
◦ security issues
◦ unit test coverage
◦ duplicated code
◦ complexity:
◦ cyclomatic complexity number
◦ number of parameters

10. Unit Testing
Don’t test trivial code!
Scope of Unit Testing:
◦ View Models
◦ Generic Algorithms
◦ Managers with business logic
◦ Complicated View Controllers
Expected incremental coverage is ~60%
◦ Code coverage is not a primary goal for unit testing!
Tools:
◦ XCTest
◦ Sonar
◦ Jenkins – add unit tests to build lifecycle
10

11. Unit testing –
Process recommendations
Write unit tests
for the code to
be refactored
Write unit tests
during bug
fixing
Start unit
testing for the
new code
11

12. Exampleofaunittest
12
class LabelValuesTests: XCTestCase {
var vc: ViewController!
override func setUp() {
super.setUp()
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
vc = storyboard.instantiateInitialViewController() as! ViewController
}
func testLabelValuesShowedProperly() {
vc.updateLabels(Float(80.0), Float(50.0), Float(40.0))
// The labels should now display 80, 50 and 40
XCTAssert(vc.numberLabel.text == "80.0", "numberLabel doesn't show the right text")
XCTAssert(vc.percentageLabel.text == "50.0%", "percentageLabel doesn't show the right text")
XCTAssert(vc.resultLabel.text == "40.0", "resultLabel doesn't show the right text")
}
override func tearDown() {
// Put teardown code here. This method is called after the invocation of each test method in the
class.
super.tearDown()
}
}