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Accessing test resources in Kotlin Multiplatform can be tricky. FileKit provides a simple solution with FileKit.projectDir.

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The Problem

In KMP, there’s no built-in way to access files in your test resources folder across all platforms. Traditional approaches like ClassLoader.getResource() don’t work consistently.

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The Solution

FileKit provides FileKit.projectDir which returns the root directory of your project. From there, you can easily navigate to your test resources: 
val resourceDirectory = FileKit.projectDir / "src/commonTest/resources"
val testFile = resourceDirectory / "test-data.txt"

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Example

Here’s a complete example of a multiplatform test that reads a file from test resources: 
import io.github.vinceglb.filekit.FileKit
import io.github.vinceglb.filekit.div
import io.github.vinceglb.filekit.readString
import kotlinx.coroutines.test.runTest
import kotlin.test.Test
import kotlin.test.assertEquals

class MyTest {
    private val resourceDirectory = FileKit.projectDir / "src/commonTest/resources"
    private val textFile = resourceDirectory / "hello.txt"
    private val imageFile = resourceDirectory / "image.png"

    @Test
    fun readTestFile() = runTest {
        val content = textFile.readString()
        assertEquals(expected = "Hello, World!", actual = content)
    }

    @Test
    fun checkFileExists() {
        assertTrue { textFile.exists() }
        assertTrue { imageFile.exists() }
    }
}

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Project Structure

Your test resources should be placed in the appropriate source set: 
my-project/
├── src/
│   ├── commonMain/
│   ├── commonTest/
│   │   ├── kotlin/
│   │   │   └── MyTest.kt
│   │   └── resources/
│   │       ├── hello.txt
│   │       └── image.png
│   └── ...
Use the / operator (via div) to build paths in a readable way:
val file = FileKit.projectDir / "src" / "commonTest" / "resources" / "data.json"

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Supported Platforms

FileKit.projectDir is available on all non-web platforms:
PlatformSupported
Android✅
iOS✅
macOS✅
JVM✅
JS❌
WASM❌