diff --git a/sidecar/src/test/kotlin/dev/uatu/sidecar/DriverServiceTest.kt b/sidecar/src/test/kotlin/dev/uatu/sidecar/DriverServiceTest.kt
new file mode 100644
index 0000000..e3b17bc
--- /dev/null
+++ b/sidecar/src/test/kotlin/dev/uatu/sidecar/DriverServiceTest.kt
@@ -0,0 +1,106 @@
+package dev.uatu.sidecar
+
+import dev.uatu.driver.v1.DriverGrpc
+import dev.uatu.driver.v1.Duration
+import dev.uatu.driver.v1.Empty
+import dev.uatu.driver.v1.LaunchRequest
+import dev.uatu.driver.v1.Point
+import dev.uatu.driver.v1.Text
+import io.grpc.ManagedChannel
+import io.grpc.inprocess.InProcessChannelBuilder
+import io.grpc.inprocess.InProcessServerBuilder
+import io.grpc.testing.GrpcCleanupRule
+import org.junit.Rule
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DriverServiceTest {
+
+    @get:Rule val grpcCleanup: GrpcCleanupRule = GrpcCleanupRule()
+
+    private fun newClient(backend: DriverBackend): DriverGrpc.DriverBlockingStub {
+        val serverName = InProcessServerBuilder.generateName()
+        val service = DriverService(platform = "android", serial = null, backend = backend)
+        grpcCleanup.register(
+            InProcessServerBuilder.forName(serverName).directExecutor().addService(service).build().start()
+        )
+        val channel: ManagedChannel = grpcCleanup.register(
+            InProcessChannelBuilder.forName(serverName).directExecutor().build()
+        )
+        return DriverGrpc.newBlockingStub(channel)
+    }
+
+    @Test fun launchAndTerminateRoundTripBundle() {
+        val backend = StubDriverBackend("android")
+        val client = newClient(backend)
+
+        client.launch(LaunchRequest.newBuilder().setBundleId("com.example").setClearState(true).build())
+        assertEquals("com.example", backend.lastBundleId)
+        assertEquals(1, backend.launchCount)
+
+        client.terminate(Empty.getDefaultInstance())
+        assertEquals(null, backend.lastBundleId)
+    }
+
+    @Test fun tapForwardsCoordinates() {
+        val backend = StubDriverBackend("android")
+        val client = newClient(backend)
+
+        client.tap(Point.newBuilder().setX(100).setY(250).build())
+        assertEquals(100 to 250, backend.lastTap)
+    }
+
+    @Test fun inputTextForwardsValue() {
+        val backend = StubDriverBackend("android")
+        val client = newClient(backend)
+
+        client.inputText(Text.newBuilder().setValue("hello world").build())
+        assertEquals("hello world", backend.lastInputText)
+    }
+
+    @Test fun screenshotReturnsBackendBytes() {
+        val backend = object : DriverBackend by StubDriverBackend("android") {
+            override fun screenshot(): Triple<ByteArray, Int, Int> = Triple(byteArrayOf(1, 2, 3), 1080, 2340)
+        }
+        val client = newClient(backend)
+
+        val image = client.screenshot(Empty.getDefaultInstance())
+        assertEquals(1080, image.width)
+        assertEquals(2340, image.height)
+        assertEquals(3, image.png.size())
+    }
+
+    @Test fun hierarchyReturnsBackendJson() {
+        val backend = object : DriverBackend by StubDriverBackend("android") {
+            override fun hierarchy(): String = "{\"x\":1}"
+        }
+        val client = newClient(backend)
+
+        val hierarchy = client.hierarchy(Empty.getDefaultInstance())
+        assertEquals("{\"x\":1}", hierarchy.json)
+    }
+
+    @Test fun waitForIdleHonorsDuration() {
+        var observed: Long = -1L
+        val backend = object : DriverBackend by StubDriverBackend("android") {
+            override fun waitForIdle(durationMillis: Long) {
+                observed = durationMillis
+            }
+        }
+        val client = newClient(backend)
+
+        client.waitForIdle(Duration.newBuilder().setMillis(123).build())
+        assertEquals(123L, observed)
+    }
+
+    @Test fun healthReportsPlatformAndVersion() {
+        val backend = StubDriverBackend("android")
+        val client = newClient(backend)
+
+        val status = client.health(Empty.getDefaultInstance())
+        assertTrue(status.ready)
+        assertEquals("android", status.platform)
+        assertEquals(DriverService.VERSION, status.version)
+    }
+}