Initial commit

src/test/kotlin/InMemoryTransport.kt

@@ -0,0 +1,58 @@
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
+import org.jetbrains.kotlinx.mcp.JSONRPCMessage
+import org.jetbrains.kotlinx.mcp.shared.Transport
+
+/**
+ * In-memory transport for creating clients and servers that talk to each other within the same process.
+ */
+class InMemoryTransport : Transport {
+    private val scope = CoroutineScope(SupervisorJob())
+
+    private var otherTransport: InMemoryTransport? = null
+    private val messageQueue: MutableList<JSONRPCMessage> = mutableListOf()
+
+    override var onClose: (() -> Unit)? = null
+    override var onError: ((Throwable) -> Unit)? = null
+    override var onMessage: (suspend ((JSONRPCMessage) -> Unit))? = null
+
+    /**
+     * Creates a pair of linked in-memory transports that can communicate with each other.
+     * One should be passed to a Client and one to a Server.
+     */
+    companion object {
+        fun createLinkedPair(): Pair<InMemoryTransport, InMemoryTransport> {
+            val clientTransport = InMemoryTransport()
+            val serverTransport = InMemoryTransport()
+            clientTransport.otherTransport = serverTransport
+            serverTransport.otherTransport = clientTransport
+            return Pair(clientTransport, serverTransport)
+        }
+    }
+
+    override suspend fun start() {
+        // Process any messages that were queued before start was called
+        while (messageQueue.isNotEmpty()) {
+            messageQueue.removeFirstOrNull()?.let { message ->
+                onMessage?.invoke(message) // todo?
+            }
+        }
+    }
+
+    override suspend fun close() {
+        val other = otherTransport
+        otherTransport = null
+        other?.close()
+        onClose?.invoke()
+    }
+
+    override suspend fun send(message: JSONRPCMessage) {
+        val other = otherTransport ?: throw IllegalStateException("Not connected")
+
+        if (other.onMessage != null) {
+            other.onMessage?.invoke(message) // todo?
+        } else {
+            other.messageQueue.add(message)
+        }
+    }
+}