diff --git a/elmslie-core/build.gradle.kts b/elmslie-core/build.gradle.kts
index aef9c419..cd9b76a3 100644
--- a/elmslie-core/build.gradle.kts
+++ b/elmslie-core/build.gradle.kts
@@ -1,11 +1,9 @@
 plugins {
     id("elmslie.kotlin-lib")
-    `java-test-fixtures`
+    id("elmslie.tests-convention")
 }
 
 dependencies {
     implementation(libs.kotlinx.coroutinesCore)
-    testFixturesImplementation(libs.kotlinx.coroutinesTest)
-    testFixturesImplementation(libs.junit)
     testImplementation(libs.kotlinx.coroutinesTest)
 }
diff --git a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/EffectCachingElmStoreTest.kt b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/EffectCachingElmStoreTest.kt
index 1bde81d8..3975fea5 100644
--- a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/EffectCachingElmStoreTest.kt
+++ b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/EffectCachingElmStoreTest.kt
@@ -1,24 +1,40 @@
 package vivid.money.elmslie.core.store
 
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.RegisterExtension
+import kotlinx.coroutines.test.setMain
+import vivid.money.elmslie.core.config.ElmslieConfig
 import vivid.money.elmslie.core.testutil.model.Command
 import vivid.money.elmslie.core.testutil.model.Effect
 import vivid.money.elmslie.core.testutil.model.Event
 import vivid.money.elmslie.core.testutil.model.State
-import vivid.money.elmslie.test.TestDispatcherExtension
 
 @OptIn(ExperimentalCoroutinesApi::class)
 class EffectCachingElmStoreTest {
 
-    @JvmField @RegisterExtension val testDispatcherExtension = TestDispatcherExtension()
+    @BeforeTest
+    fun beforeEach() {
+        val testDispatcher = StandardTestDispatcher()
+        ElmslieConfig.ioDispatchers { testDispatcher }
+        Dispatchers.setMain(testDispatcher)
+    }
+
+
+    @AfterTest
+    fun afterEach() {
+        Dispatchers.resetMain()
+    }
 
     @Test
     fun `Should collect effects which are emitted before collecting flow`() = runTest {
diff --git a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/ElmStoreTest.kt b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/ElmStoreTest.kt
index 5b540dd2..7d9ac77f 100644
--- a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/ElmStoreTest.kt
+++ b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/ElmStoreTest.kt
@@ -1,5 +1,10 @@
 package vivid.money.elmslie.core.store
 
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
@@ -8,22 +13,33 @@ import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.RegisterExtension
+import kotlinx.coroutines.test.setMain
+import vivid.money.elmslie.core.config.ElmslieConfig
 import vivid.money.elmslie.core.testutil.model.Command
 import vivid.money.elmslie.core.testutil.model.Effect
 import vivid.money.elmslie.core.testutil.model.Event
 import vivid.money.elmslie.core.testutil.model.State
-import vivid.money.elmslie.test.TestDispatcherExtension
 
 @OptIn(ExperimentalCoroutinesApi::class)
 class ElmStoreTest {
 
-    @JvmField @RegisterExtension val testDispatcherExtension = TestDispatcherExtension()
+    @BeforeTest
+    fun beforeEach() {
+        val testDispatcher = StandardTestDispatcher()
+        ElmslieConfig.ioDispatchers { testDispatcher }
+        Dispatchers.setMain(testDispatcher)
+    }
+
+
+    @AfterTest
+    fun afterEach() {
+        Dispatchers.resetMain()
+    }
 
     @Test
     fun `Should stop the store properly`() = runTest {
diff --git a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/DslReducerTest.kt b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/DslReducerTest.kt
index c6c64a6b..171c0769 100644
--- a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/DslReducerTest.kt
+++ b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/DslReducerTest.kt
@@ -1,8 +1,8 @@
 package vivid.money.elmslie.core.store.dsl
 
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Assertions.assertTrue
-import org.junit.jupiter.api.Test
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 private object BasicDslReducer : DslReducer<TestEvent, TestState, TestEffect, TestCommand>() {
 
diff --git a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/ScreenDslReducerTest.kt b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/ScreenDslReducerTest.kt
index 63784c39..ba6f5a87 100644
--- a/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/ScreenDslReducerTest.kt
+++ b/elmslie-core/src/test/java/vivid/money/elmslie/core/store/dsl/ScreenDslReducerTest.kt
@@ -1,8 +1,8 @@
 package vivid.money.elmslie.core.store.dsl
 
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Assertions.assertTrue
-import org.junit.jupiter.api.Test
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 object BasicScreenDslReducer :
     ScreenDslReducer<
diff --git a/elmslie-core/src/testFixtures/kotlin/vivid/money/elmslie/test/TestDispatcherExtension.kt b/elmslie-core/src/testFixtures/kotlin/vivid/money/elmslie/test/TestDispatcherExtension.kt
deleted file mode 100644
index 9b133b16..00000000
--- a/elmslie-core/src/testFixtures/kotlin/vivid/money/elmslie/test/TestDispatcherExtension.kt
+++ /dev/null
@@ -1,27 +0,0 @@
-package vivid.money.elmslie.test
-
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.test.StandardTestDispatcher
-import kotlinx.coroutines.test.TestDispatcher
-import kotlinx.coroutines.test.resetMain
-import kotlinx.coroutines.test.setMain
-import org.junit.jupiter.api.extension.AfterEachCallback
-import org.junit.jupiter.api.extension.BeforeEachCallback
-import org.junit.jupiter.api.extension.ExtensionContext
-import vivid.money.elmslie.core.config.ElmslieConfig
-
-@OptIn(ExperimentalCoroutinesApi::class)
-class TestDispatcherExtension(
-    private val testDispatcher: TestDispatcher = StandardTestDispatcher(),
-) : BeforeEachCallback, AfterEachCallback {
-
-    override fun beforeEach(context: ExtensionContext?) {
-        ElmslieConfig.ioDispatchers { testDispatcher }
-        Dispatchers.setMain(testDispatcher)
-    }
-
-    override fun afterEach(context: ExtensionContext?) {
-        Dispatchers.resetMain()
-    }
-}
diff --git a/samples/kotlin-calculator/build.gradle.kts b/samples/kotlin-calculator/build.gradle.kts
index 17c357cb..2ca7a590 100644
--- a/samples/kotlin-calculator/build.gradle.kts
+++ b/samples/kotlin-calculator/build.gradle.kts
@@ -8,6 +8,6 @@ dependencies {
     implementation(projects.elmslieCore)
     implementation(libs.kotlinx.coroutinesCore)
 
+    testImplementation(projects.elmslieCore)
     testImplementation(libs.kotlinx.coroutinesTest)
-    testImplementation(testFixtures(projects.elmslieCore))
 }
diff --git a/samples/kotlin-calculator/src/test/java/vivid/money/elmslie/samples/calculator/StoreTest.kt b/samples/kotlin-calculator/src/test/java/vivid/money/elmslie/samples/calculator/StoreTest.kt
index a2d917a9..f4d66de6 100644
--- a/samples/kotlin-calculator/src/test/java/vivid/money/elmslie/samples/calculator/StoreTest.kt
+++ b/samples/kotlin-calculator/src/test/java/vivid/money/elmslie/samples/calculator/StoreTest.kt
@@ -1,19 +1,35 @@
 package vivid.money.elmslie.samples.calculator
 
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
 import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.runTest
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.extension.RegisterExtension
-import vivid.money.elmslie.test.TestDispatcherExtension
+import kotlinx.coroutines.test.setMain
+import vivid.money.elmslie.core.config.ElmslieConfig
 
 @OptIn(ExperimentalCoroutinesApi::class)
 internal class StoreTest {
 
-    @JvmField @RegisterExtension val testDispatcherExtension = TestDispatcherExtension()
+    @BeforeTest
+    fun beforeEach() {
+        val testDispatcher = StandardTestDispatcher()
+        ElmslieConfig.ioDispatchers { testDispatcher }
+        Dispatchers.setMain(testDispatcher)
+    }
+
+
+    @AfterTest
+    fun afterEach() {
+        Dispatchers.resetMain()
+    }
 
     @Test
     fun `1 + 1 = 2`() = runTest {