Throw IOException if negative int from port-based cli connection stream.

-Instead of failing at initializing array with negative size.
Introducing PowerMock test for the zero-size array case.
Negative-size case not tested thx to unhelping PowerMock behavior.
Using ConnectionMockTest instead of ConnectionTest; needed by PowerMock.

cli/src/test/java/hudson/cli/ConnectionMockTest.java

@@ -0,0 +1,56 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2013 Ericsson
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package hudson.cli;
+
+import hudson.remoting.FastPipedInputStream;
+import hudson.remoting.FastPipedOutputStream;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.powermock.api.mockito.PowerMockito.*;
+
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+/**
+ * @author marco.miller@ericsson.com
+ */
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({Connection.class})
+public class ConnectionMockTest {
+
+    @Test
+    public void shouldTolerateEmptyByteArrayUponStreamZeroValue() throws IOException {
+        DataInputStream din = mock(DataInputStream.class);
+        //when(din.readInt()).thenReturn(0) does not work; mock always return 0 for some TBD reason
+        Connection c = new Connection(din, new FastPipedOutputStream(new FastPipedInputStream()));
+        assertTrue(c.readByteArray().length == 0);
+    }
+}