Fix #84

Author: ileasile

src/main/kotlin/org/jetbrains/kotlin/jupyter/connection.kt

@@ -95,8 +95,8 @@ class JupyterConnection(val config: KernelConfig): Closeable {
                 currentBuf = null
                 return -1
             }
-            currentBufPos.inc()
-            return buf[currentBufPos - 1].toInt()
+
+            return buf[currentBufPos++].toInt()
         }
 
         @Synchronized

src/test/kotlin/org/jetbrains/kotlin/jupyter/test/executeTests.kt

@@ -5,6 +5,7 @@ import org.jetbrains.kotlin.jupyter.*
 import org.junit.Assert
 import org.junit.Test
 import org.zeromq.ZMQ
+import kotlin.test.assertEquals
 
 fun Message.type(): String {
     return header!!["msg_type"] as String
@@ -132,4 +133,14 @@ class ExecuteTests : KernelServerTestsBase() {
         val res = doExecute(code, false, ::checker)
         Assert.assertNull(res)
     }
+
+    @Test
+    fun testReadLine() {
+        val code = """
+            val answer = readLine()
+            answer
+        """.trimIndent()
+        val res = doExecute(code, inputs = listOf("42"))
+        assertEquals(jsonObject("text/plain" to "42"), res)
+    }
 }