Add comprehensive test suite with 94%+ instruction coverage

[devin-ai-integration]

Summary

Adds a comprehensive test suite to achieve 94.2% instruction coverage and 92.2% line coverage (well above the 85% target). The repo previously had zero tests.

Changes:

• Fixed pom.xml packaging from pom to jar for proper Spring Boot builds
• Added spring-boot-starter-test dependency for testing framework
• Added JaCoCo Maven plugin for coverage reporting
• Overrode Mockito/ByteBuddy versions for Java 11 compatibility
• Added 63 tests across 11 test classes covering all source files:
  • Models: Customer, Greeting, Quote, Topic, Value (getters, setters, constructors, toString)
  • SimpleTimeClient: setTime, setDate, setDateAndTime, getZonedDateTime (valid + invalid zones)
  • TimeClient interface: static getZoneId method (valid + invalid zones)
  • CustomPredicate interface: lambda predicate usage with String and Integer
  • TopicService: all 15 service methods including CRUD, filtering, sorting, string operations, file operations
  • Controllers: GreetingController, TopicController, HelloController via standalone MockMvc
  • Application: restTemplate bean, CommandLineRunner, JDBC operations

Coverage by class (JaCoCo instruction coverage):

Class	Missed	Covered	Coverage
All controllers	0	223	100%
All models	0	241	100%
TopicService	12	357	96.7%
TimeClient	0	24	100%
Application	48	130	73.0%
Total	60	975	94.2%

Review & Testing Checklist for Human

• Run mvn test with Java 11 (JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64) to verify all 63 tests pass
• Check JaCoCo report at target/site/jacoco/index.html to verify coverage meets 85%+ threshold
• Verify the pom.xml packaging change from pom to jar doesn't affect existing build/deploy workflows

Notes

• The project targets Java 8 (<java.version>1.8</java.version>) but tests require Java 11+ due to the bundled Mockito/ByteBuddy version. Mockito 2.28.2 and ByteBuddy 1.9.16 are overridden in properties for compatibility.
• The Application.main() method is not directly tested because it calls an external API (gturnquist-quoters.cfapps.io) that is no longer available. The restTemplate bean, CommandLineRunner, and JDBC run() methods are tested individually.

Link to Devin session: https://app.devin.ai/sessions/5460f935c97d4fd6871773352638330b
Requested by: @bnob-git

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[devin-ai-integration]

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