Name: jbaruch/kotlin-tutor
Rating: 98.85 (1 reviews)
Author: jbaruch

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jbaruch/kotlin-tutor

Teaches AI agents to write idiomatic Kotlin instead of Java-in-a-.kt-file.

1.20x

Quality

98%

Does it follow best practices?

Impact

99%

1.20x

Average score across 8 eval scenarios

Securityby

Passed

No known issues

Evaluation results

100%

24%

Calculator Test Migration

JUnit assertion mapping to Kotest equivalents

Criteria

Without context

With context

assertEquals order

100%

withClue for message

100%

shouldThrow

100%

shouldBeTrue

50%

100%

shouldBeFalse

50%

100%

shouldBeNull

100%

shouldNotBeNull

100%

JUnit imports removed

100%

Kotest imports added

100%

Imports sorted

100%

94%

Test Suite Modernisation and Verification

File discovery, conversion, and verification script gate

Criteria

Without context

With context

Both files converted

100%

Kotest assertions used

100%

No JUnit imports remain

100%

Verify script executed

100%

Script exit code documented

100%

File list in report

100%

Files found via glob

40%

No commit performed

100%

29%

Test Suite Migration for Core Utilities

Spec style selection and lifecycle hook migration

Criteria

Without context

With context

StringSpec for flat tests

100%

BehaviorSpec for given/when/then

100%

Tests in string blocks

50%

100%

beforeEach block used

100%

Setup code preserved

100%

Correct class declaration

66%

100%

Kotest spec import present

70%

100%

JUnit annotations removed

100%

User Repository API Modernisation

Optional API cleanup: Kotlin repository returning Optional<T> and using orElse/ifPresent/map/orElseThrow → idiomatic Kotlin nullable types with safe-call, elvis, and let. Caller code must be updated alongside.

Criteria

Without context

With context

No java.util.Optional import

100%

findById returns User?

100%

findByEmail returns User?

100%

displayNameFor uses elvis

100%

sendWelcome uses ?.let

100%

requireById uses elvis throw

100%

Optional.map replaced with ?.let

100%

UserService caller updated

100%

No !! introduced

100%

Subscription Model Modernisation

POJO refactor: Java-style class with manual equals/hashCode/toString and bean accessors → idiomatic Kotlin value type

Criteria

Without context

With context

Declared as data class

100%

Properties use val

100%

No manual equals/hashCode/toString

100%

No Java-bean accessors

100%

Field order preserved

100%

All seven fields retained

100%

Todo App

Implement a small todo-list application with addTask and markComplete operations.

Criteria

Without context

With context

addTask works

100%

markComplete works

100%

Todo App

Implement a small todo-list application with addTask and markComplete operations.

Criteria

Without context

With context

addTask works

100%

markComplete works

100%

81%

Todo App

Implement a small todo-list application with addTask and markComplete operations.

Criteria

Without context

With context

Written in Kotlin

100%

Task is a data class

100%

Properties default to val

100%

Nullable types use ?

100%

No manual equals/hashCode/toString

50%

100%

addTask works

70%

100%

markComplete works

70%

100%

Evaluated: about 20 hours ago
Agent: Claude
Model: Claude Sonnet 4.6

Table of Contents

Calculator Test Migration Test Suite Modernisation and Verification Test Suite Migration for Core Utilities User Repository API Modernisation Subscription Model Modernisation Todo App Todo App Todo App