Initial commit

src/test/kotlin/shared/ReadBufferTest.kt

@@ -0,0 +1,58 @@
+package shared
+
+import org.jetbrains.kotlinx.mcp.JSONRPCMessage
+import org.jetbrains.kotlinx.mcp.JSONRPCNotification
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import org.jetbrains.kotlinx.mcp.shared.ReadBuffer
+import org.jetbrains.kotlinx.mcp.shared.serializeMessage
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
+import java.nio.charset.StandardCharsets
+
+class ReadBufferTest {
+    private val testMessage: JSONRPCMessage = JSONRPCNotification(method = "foobar")
+
+    private val json = Json { 
+        ignoreUnknownKeys = true 
+        encodeDefaults = true
+    }
+
+    @Test
+    fun `should have no messages after initialization`() {
+        val readBuffer = ReadBuffer()
+        assertNull(readBuffer.readMessage())
+    }
+
+    @Test
+    fun `should only yield a message after a newline`() {
+        val readBuffer = ReadBuffer()
+
+        // Append message without newline
+        val messageBytes = json.encodeToString(testMessage)
+            .toByteArray(StandardCharsets.UTF_8)
+        readBuffer.append(messageBytes)
+        assertNull(readBuffer.readMessage())
+
+        // Append newline and verify message is now available
+        readBuffer.append("\n".toByteArray(StandardCharsets.UTF_8))
+        assertEquals(testMessage, readBuffer.readMessage())
+        assertNull(readBuffer.readMessage())
+    }
+
+    @Test
+    fun `should be reusable after clearing`() {
+        val readBuffer = ReadBuffer()
+
+        readBuffer.append("foobar".toByteArray(Charsets.UTF_8))
+        readBuffer.clear()
+        assertNull(readBuffer.readMessage())
+
+        val messageJson = serializeMessage(testMessage)
+        readBuffer.append(messageJson.toByteArray(Charsets.UTF_8))
+        readBuffer.append("\n".toByteArray(Charsets.UTF_8))
+        val message = readBuffer.readMessage()
+        assertEquals(testMessage, message)
+    }
+}