StreamIdSupplier returns 1,3,5... or 2,4,6... (#213)

Tighten `StreamIdSupplier.isValid()` check and start stream ids from 1

Author: yschimke

reactivesocket-core/src/main/java/io/reactivesocket/ClientReactiveSocket.java

@@ -301,7 +301,7 @@ private void handleFrame(int streamId, FrameType type, Frame frame) {
     }
 
     private void handleMissingResponseProcessor(int streamId, FrameType type, Frame frame) {
-        if (!streamIdSupplier.isValid(streamId)) {
+        if (!streamIdSupplier.isBeforeOrCurrent(streamId)) {
             if (type == FrameType.ERROR) {
                 // message for stream that has never existed, we have a problem with
                 // the overall connection and must tear down

reactivesocket-core/src/main/java/io/reactivesocket/StreamIdSupplier.java

@@ -29,15 +29,15 @@ public synchronized int nextStreamId() {
         return streamId;
     }
 
-    public synchronized boolean isValid(int streamId) {
-        return this.streamId < streamId;
+    public synchronized boolean isBeforeOrCurrent(int streamId) {
+        return this.streamId >= streamId && streamId > 0;
     }
 
     public static StreamIdSupplier clientSupplier() {
-        return new StreamIdSupplier(1);
+        return new StreamIdSupplier(-1);
     }
 
     public static StreamIdSupplier serverSupplier() {
-        return new StreamIdSupplier(2);
+        return new StreamIdSupplier(0);
     }
 }

reactivesocket-core/src/test/java/io/reactivesocket/StreamIdSupplierTest.java

@@ -0,0 +1,69 @@
+package io.reactivesocket;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class StreamIdSupplierTest {
+    @Test
+    public void testClientSequence() {
+        StreamIdSupplier s = StreamIdSupplier.clientSupplier();
+        assertEquals(1, s.nextStreamId());
+        assertEquals(3, s.nextStreamId());
+        assertEquals(5, s.nextStreamId());
+    }
+
+    @Test
+    public void testServerSequence() {
+        StreamIdSupplier s = StreamIdSupplier.serverSupplier();
+        assertEquals(2, s.nextStreamId());
+        assertEquals(4, s.nextStreamId());
+        assertEquals(6, s.nextStreamId());
+    }
+
+    @Test
+    public void testClientIsValid() {
+        StreamIdSupplier s = StreamIdSupplier.clientSupplier();
+
+        assertFalse(s.isBeforeOrCurrent(1));
+        assertFalse(s.isBeforeOrCurrent(3));
+
+        s.nextStreamId();
+        assertTrue(s.isBeforeOrCurrent(1));
+        assertFalse(s.isBeforeOrCurrent(3));
+
+        s.nextStreamId();
+        assertTrue(s.isBeforeOrCurrent(3));
+
+        // negative
+        assertFalse(s.isBeforeOrCurrent(-1));
+        // connection
+        assertFalse(s.isBeforeOrCurrent(0));
+        // server also accepted (checked externally)
+        assertTrue(s.isBeforeOrCurrent(2));
+    }
+
+    @Test
+    public void testServerIsValid() {
+        StreamIdSupplier s = StreamIdSupplier.serverSupplier();
+
+        assertFalse(s.isBeforeOrCurrent(2));
+        assertFalse(s.isBeforeOrCurrent(4));
+
+        s.nextStreamId();
+        assertTrue(s.isBeforeOrCurrent(2));
+        assertFalse(s.isBeforeOrCurrent(4));
+
+        s.nextStreamId();
+        assertTrue(s.isBeforeOrCurrent(4));
+
+        // negative
+        assertFalse(s.isBeforeOrCurrent(-2));
+        // connection
+        assertFalse(s.isBeforeOrCurrent(0));
+        // client also accepted (checked externally)
+        assertTrue(s.isBeforeOrCurrent(1));
+    }
+}