diff --git a/radioplayer/build.gradle.kts b/radioplayer/build.gradle.kts
index 1a87f8f..455cc6b 100644
--- a/radioplayer/build.gradle.kts
+++ b/radioplayer/build.gradle.kts
@@ -15,10 +15,9 @@ swiftklib {
 }
 
 kotlin {
-    androidTarget {
+    androidTarget {}
+    jvm()
 
-    }
-    
     val xcf = XCFramework()
     listOf(
         iosX64(),
diff --git a/radioplayer/src/jvmMain/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayer.jvm.kt b/radioplayer/src/jvmMain/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayer.jvm.kt
new file mode 100644
index 0000000..273f20e
--- /dev/null
+++ b/radioplayer/src/jvmMain/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayer.jvm.kt
@@ -0,0 +1,47 @@
+package dev.markturnip.radioplayer
+
+actual final class PlatformMediaPlayer actual constructor() {
+
+    private val stateCallbacks = mutableListOf<(PlaybackState) -> Unit>()
+    private val progressCallbacks = mutableListOf<(Progress) -> Unit>()
+
+    var currentState: PlaybackState = PlaybackState.STOPPED
+        private set
+
+    actual fun playItem(mediaPlayerItem: MediaPlayerItem) {
+        updateState(PlaybackState.PLAYING)
+    }
+
+    actual fun play() {
+        updateState(PlaybackState.PLAYING)
+    }
+
+    actual fun pause() {
+        updateState(PlaybackState.PAUSED)
+    }
+
+    actual fun stop() {
+        updateState(PlaybackState.STOPPED)
+    }
+
+    actual fun skip(delta: Double) {}
+
+    actual fun seekWithPosition(position: Double) {}
+
+    actual fun subscribeState(callback: (PlaybackState) -> Unit) {
+        stateCallbacks += callback
+    }
+
+    actual fun subscribeProgress(callback: (Progress) -> Unit) {
+        progressCallbacks += callback
+    }
+
+    fun emitProgress(progress: Progress) {
+        progressCallbacks.forEach { it(progress) }
+    }
+
+    private fun updateState(newState: PlaybackState) {
+        currentState = newState
+        stateCallbacks.forEach { it(newState) }
+    }
+}
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 55a8d81..70e14c3 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -18,4 +18,5 @@ dependencyResolutionManagement {
 }
 
 rootProject.name = "radioplayer-kt"
-include(":radioplayer")
\ No newline at end of file
+include(":radioplayer")
+include(":tests")
\ No newline at end of file
diff --git a/tests/build.gradle.kts b/tests/build.gradle.kts
new file mode 100644
index 0000000..9b12303
--- /dev/null
+++ b/tests/build.gradle.kts
@@ -0,0 +1,20 @@
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+}
+
+kotlin {
+    jvm()
+
+    listOf(
+        iosX64(),
+        iosArm64(),
+        iosSimulatorArm64()
+    )
+
+    sourceSets {
+        commonTest.dependencies {
+            implementation(libs.kotlin.test)
+            implementation(projects.radioplayer)
+        }
+    }
+}
diff --git a/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/MediaPlayerItemTest.kt b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/MediaPlayerItemTest.kt
new file mode 100644
index 0000000..ab94cb4
--- /dev/null
+++ b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/MediaPlayerItemTest.kt
@@ -0,0 +1,53 @@
+package dev.markturnip.radioplayer
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class MediaPlayerItemTest {
+
+    private class TestMediaPlayerItem(
+        override val id: String,
+        override val title: String,
+        override val artist: String?,
+        override val url: String,
+        override val isLive: Boolean,
+        override val artworkUrl: String?
+    ) : MediaPlayerItem
+
+    @Test
+    fun testLiveRadioStation() {
+        val station = TestMediaPlayerItem(
+            id = "station-1",
+            title = "BBC Radio 1",
+            artist = null,
+            url = "https://stream.example.com/radio1.mp3",
+            isLive = true,
+            artworkUrl = "https://example.com/artwork.png"
+        )
+        assertEquals("station-1", station.id)
+        assertEquals("BBC Radio 1", station.title)
+        assertNull(station.artist)
+        assertTrue(station.isLive)
+        assertEquals("https://stream.example.com/radio1.mp3", station.url)
+        assertEquals("https://example.com/artwork.png", station.artworkUrl)
+    }
+
+    @Test
+    fun testOnDemandTrack() {
+        val track = TestMediaPlayerItem(
+            id = "track-42",
+            title = "Blue (Da Ba Dee)",
+            artist = "Eiffel 65",
+            url = "https://stream.example.com/track42.mp3",
+            isLive = false,
+            artworkUrl = null
+        )
+        assertEquals("track-42", track.id)
+        assertEquals("Eiffel 65", track.artist)
+        assertFalse(track.isLive)
+        assertNull(track.artworkUrl)
+    }
+}
diff --git a/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerTest.kt b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerTest.kt
new file mode 100644
index 0000000..9ea9b66
--- /dev/null
+++ b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerTest.kt
@@ -0,0 +1,62 @@
+package dev.markturnip.radioplayer
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class PlatformMediaPlayerTest {
+
+    private class TestMediaPlayerItem(
+        override val id: String = "test-id",
+        override val title: String = "Test Track",
+        override val artist: String? = "Test Artist",
+        override val url: String = "https://stream.example.com/test.mp3",
+        override val isLive: Boolean = false,
+        override val artworkUrl: String? = null
+    ) : MediaPlayerItem
+
+    @Test
+    fun testPlayTransitionsToPlayingState() {
+        val player = PlatformMediaPlayer()
+        val states = mutableListOf<PlaybackState>()
+        player.subscribeState { states += it }
+
+        player.play()
+
+        assertEquals(listOf(PlaybackState.PLAYING), states)
+    }
+
+    @Test
+    fun testPauseTransitionsToPausedState() {
+        val player = PlatformMediaPlayer()
+        val states = mutableListOf<PlaybackState>()
+        player.subscribeState { states += it }
+
+        player.play()
+        player.pause()
+
+        assertEquals(listOf(PlaybackState.PLAYING, PlaybackState.PAUSED), states)
+    }
+
+    @Test
+    fun testStopTransitionsToStoppedState() {
+        val player = PlatformMediaPlayer()
+        val states = mutableListOf<PlaybackState>()
+        player.subscribeState { states += it }
+
+        player.play()
+        player.stop()
+
+        assertEquals(listOf(PlaybackState.PLAYING, PlaybackState.STOPPED), states)
+    }
+
+    @Test
+    fun testPlayItemTransitionsToPlayingState() {
+        val player = PlatformMediaPlayer()
+        val states = mutableListOf<PlaybackState>()
+        player.subscribeState { states += it }
+
+        player.playItem(TestMediaPlayerItem())
+
+        assertEquals(listOf(PlaybackState.PLAYING), states)
+    }
+}
diff --git a/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlaybackStateTest.kt b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlaybackStateTest.kt
new file mode 100644
index 0000000..30c299a
--- /dev/null
+++ b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/PlaybackStateTest.kt
@@ -0,0 +1,39 @@
+package dev.markturnip.radioplayer
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+import kotlin.test.assertTrue
+
+class PlaybackStateTest {
+
+    @Test
+    fun testAllStatesExist() {
+        val states = PlaybackState.entries
+        assertTrue(states.contains(PlaybackState.PLAYING))
+        assertTrue(states.contains(PlaybackState.PAUSED))
+        assertTrue(states.contains(PlaybackState.STOPPED))
+        assertTrue(states.contains(PlaybackState.BUFFERING))
+        assertTrue(states.contains(PlaybackState.ERROR))
+    }
+
+    @Test
+    fun testStateEquality() {
+        assertEquals(PlaybackState.PLAYING, PlaybackState.PLAYING)
+        assertNotEquals(PlaybackState.PLAYING, PlaybackState.PAUSED)
+    }
+
+    @Test
+    fun testStateNames() {
+        assertEquals("PLAYING", PlaybackState.PLAYING.name)
+        assertEquals("PAUSED", PlaybackState.PAUSED.name)
+        assertEquals("STOPPED", PlaybackState.STOPPED.name)
+        assertEquals("BUFFERING", PlaybackState.BUFFERING.name)
+        assertEquals("ERROR", PlaybackState.ERROR.name)
+    }
+
+    @Test
+    fun testStateCount() {
+        assertEquals(5, PlaybackState.entries.size)
+    }
+}
diff --git a/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/ProgressTest.kt b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/ProgressTest.kt
new file mode 100644
index 0000000..d0b3e29
--- /dev/null
+++ b/tests/src/commonTest/kotlin/dev/markturnip/radioplayer/ProgressTest.kt
@@ -0,0 +1,43 @@
+package dev.markturnip.radioplayer
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+class ProgressTest {
+
+    @Test
+    fun testEquality() {
+        val p1 = Progress(elapsed = 30.0, duration = 120.0)
+        val p2 = Progress(elapsed = 30.0, duration = 120.0)
+        assertEquals(p1, p2)
+    }
+
+    @Test
+    fun testInequality() {
+        val p1 = Progress(elapsed = 30.0, duration = 120.0)
+        val p2 = Progress(elapsed = 60.0, duration = 120.0)
+        assertNotEquals(p1, p2)
+    }
+
+    @Test
+    fun testCopy() {
+        val original = Progress(elapsed = 30.0, duration = 120.0)
+        val updated = original.copy(elapsed = 60.0)
+        assertEquals(60.0, updated.elapsed)
+        assertEquals(120.0, updated.duration)
+    }
+
+    @Test
+    fun testElapsedDurationRatio() {
+        val progress = Progress(elapsed = 30.0, duration = 120.0)
+        assertEquals(0.25, progress.elapsed / progress.duration)
+    }
+
+    @Test
+    fun testZeroElapsedWithNonZeroDuration() {
+        val progress = Progress(elapsed = 0.0, duration = 120.0)
+        assertEquals(0.0, progress.elapsed)
+        assertEquals(0.0, progress.elapsed / progress.duration)
+    }
+}
diff --git a/tests/src/jvmTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerJvmTest.kt b/tests/src/jvmTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerJvmTest.kt
new file mode 100644
index 0000000..3d37888
--- /dev/null
+++ b/tests/src/jvmTest/kotlin/dev/markturnip/radioplayer/PlatformMediaPlayerJvmTest.kt
@@ -0,0 +1,38 @@
+package dev.markturnip.radioplayer
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class PlatformMediaPlayerJvmTest {
+
+    @Test
+    fun testInitialStateIsStopped() {
+        val player = PlatformMediaPlayer()
+        assertEquals(PlaybackState.STOPPED, player.currentState)
+    }
+
+    @Test
+    fun testCurrentStateReflectsPlayPauseStop() {
+        val player = PlatformMediaPlayer()
+        player.play()
+        assertEquals(PlaybackState.PLAYING, player.currentState)
+        player.pause()
+        assertEquals(PlaybackState.PAUSED, player.currentState)
+        player.stop()
+        assertEquals(PlaybackState.STOPPED, player.currentState)
+    }
+
+    @Test
+    fun testSubscribeProgressReceivesEmittedUpdates() {
+        val player = PlatformMediaPlayer()
+        val received = mutableListOf<Progress>()
+        player.subscribeProgress { received += it }
+
+        player.emitProgress(Progress(elapsed = 10.0, duration = 180.0))
+        player.emitProgress(Progress(elapsed = 20.0, duration = 180.0))
+
+        assertEquals(2, received.size)
+        assertEquals(10.0, received[0].elapsed)
+        assertEquals(20.0, received[1].elapsed)
+    }
+}