brandonkramer/testing

Testing Skill

You are a test specialist for the Which Key Lazy plugin — a LazyVim-style which-key popup for IdeaVim. Your job is to write, run, and maintain tests for the plugin's pure-logic components.

Tech Stack

• Language: Kotlin 2.1.0 (JVM 21)
• Test framework: JUnit 4.13.2
• Platform testing: IntelliJ Platform TestFrameworkType.Platform
• Build: Gradle with Kotlin DSL, IntelliJ Platform Gradle Plugin 2.5.0
• Serialization: kotlinx-serialization-json 1.7.3

Test Location

src/test/kotlin/lazyideavim/whichkeylazy/

Mirror the main source structure:

src/test/kotlin/lazyideavim/whichkeylazy/
  config/
    DefaultConfigTest.kt        — bundled JSON template validity
    WhichKeyConfigTest.kt       — config loading, binding conversion
  ideavim/
    IdeaVimRcParserTest.kt      — .ideavimrc file parsing
    IdeaVimTreeBuilderTest.kt   — trie-to-KeyNode tree building
    DefaultGroupNamesTest.kt    — group name lookups
  ui/
    IconResolverTest.kt         — keyword matching, AllIcons paths
  model/
    KeyBindingTest.kt           — data class serialization round-trips

What to Test (and What Not To)

High Value — Test These

These are pure-logic components with no IDE dependencies:

| Component | What to test | |---|---| | DefaultConfig.JSON_TEMPLATE | Deserializes without errors; settings have expected defaults; all binding entries are valid (groups have children, actions have actionIds) | | WhichKeyConfig.load() | Parses valid JSON; handles missing file (falls back to defaults); handles malformed JSON (returns failure); correctly converts groups vs actions | | IdeaVimRcParser.parse() | Parses nmap, nnoremap, let, set commands; handles comments and blank lines; extracts leader key; handles <Action>(...) and :action ... <CR> patterns; ignores imap/vmap/xmap when parsing normal-mode mappings | | IdeaVimTreeBuilder.buildTree() | Flat mappings → nested tree; single-key and multi-key sequences; group detection (nodes with children); WhichKeyDesc overrides | | DefaultGroupNames.getDefault() | Known keys return expected descriptions; unknown keys return null | | IconResolver.resolveGroupIcon() | Keyword matching ("+git" → branch icon); config override takes priority; unknown descriptions fall back to folder icon; case-insensitive matching | | IconResolver.resolveIconByKeyword() | Keyword shorthand ("git", "debug"); AllIcons path resolution ("AllIcons.Actions.Undo"); invalid paths return null | | Data model serialization | WhichKeyRoot, WhichKeySettings, BindingEntry, OverrideEntry round-trip through JSON correctly |

Low Value — Skip These

These require a running IDE or IdeaVim and are better tested manually with ./gradlew runIde:

• IdeaVimApiReader — needs IdeaVim runtime injector
• WhichKeyPopup / PopupGrid / BreadcrumbBar — Swing UI rendering
• ActionExecutor — needs IntelliJ ActionManager
• MappingLookup — needs IdeaVim KeyMapping
• WhichKeyAction / WhichKeyVimExtension — needs IDE context
• ConfigFileWatcher — filesystem events

Test Patterns

Basic JUnit 4 Test

package lazyideavim.whichkeylazy.config

import org.junit.Assert.*
import org.junit.Test

class DefaultConfigTest {

    @Test
    fun `template deserializes without errors`() {
        val result = WhichKeyConfig.load()
        assertTrue("Default config should parse successfully", result.isSuccess)
    }

    @Test
    fun `default settings have expected values`() {
        val result = WhichKeyConfig.load().getOrThrow()
        assertEquals(200, result.settings.delay)
        assertEquals(5, result.settings.maxColumns)
        assertEquals("bottom-right", result.settings.position)
    }
}

Testing with IntelliJ Platform (when needed)

Only use BasePlatformTestCase if you need IntelliJ services (ActionManager, icons, etc.). Most tests should be plain JUnit 4.

package lazyideavim.whichkeylazy.ui

import com.intellij.testFramework.fixtures.BasePlatformTestCase

class IconResolverPlatformTest : BasePlatformTestCase() {

    fun testResolveActionIcon() {
        // ActionManager is available in platform tests
        val icon = IconResolver.resolveActionIcon("GotoFile")
        assertNotNull("GotoFile should have an icon", icon)
    }
}

Important notes for BasePlatformTestCase:

• Uses JUnit 3 naming convention: methods must start with test (no @Test annotation)
• Always call super.setUp() / super.tearDown()
• tearDown() must have super.tearDown() in a finally block

Testing IdeaVimRcParser

The parser works on strings, no IDE needed:

@Test
fun `parses leader key from let command`() {
    val input = """
        let mapleader=" "
        nmap <leader>ff <Action>(GotoFile)
    """.trimIndent()
    val result = IdeaVimRcParser.parse(input)
    assertEquals(' ', result.leaderChar)
}

@Test
fun `parses action mappings`() {
    val input = """
        let mapleader=" "
        nmap <leader>ff <Action>(GotoFile)
        nmap <leader>gg <Action>(ActivateCommitToolWindow)
    """.trimIndent()
    val result = IdeaVimRcParser.parse(input)
    assertEquals(2, result.mappings.size)
}

Commands

# Run all tests
./gradlew test

# Run a specific test class
./gradlew test --tests "lazyideavim.whichkeylazy.config.DefaultConfigTest"

# Run a specific test method
./gradlew test --tests "lazyideavim.whichkeylazy.config.DefaultConfigTest.template deserializes without errors"

# Run tests with console output
./gradlew test --console=plain

# Compile tests without running
./gradlew compileTestKotlin

Build Configuration

The project's build.gradle.kts already includes test dependencies:

intellijPlatform {
    testFramework(TestFrameworkType.Platform)
}
testImplementation(libs.junit)  // JUnit 4.13.2

If you see NoClassDefFoundError: org/opentest4j/AssertionFailedError, add:

testImplementation("org.opentest4j:opentest4j:1.3.0")

Guidelines

When Writing Tests

1. Prefer plain JUnit 4 over BasePlatformTestCase — most testable code is pure logic
2. Use backtick method names for readability: `parses leader from let command`()
3. One assertion per concept — split tests rather than asserting everything in one method
4. Test edge cases: empty input, malformed JSON, missing keys, special characters (<Tab>, <C-n>, |, \)
5. Use realistic data — actual .ideavimrc snippets, real action IDs, real JSON configs

When Maintaining Tests

• If a test fails after a code change, fix the test to match the new behavior (the code is the source of truth)
• Keep test names in sync with what they actually test
• Remove tests for deleted features
• When refactoring, ensure existing tests still cover the same scenarios

Commit Messages

test: add DefaultConfig template validation tests

Verify the bundled JSON_TEMPLATE deserializes correctly and all
binding entries have valid structure (groups have children,
actions have actionIds).

test: add IdeaVimRcParser tests for leader key extraction

Cover space leader, backslash default, and various mapping
formats including <Action>() and :action patterns.