Add regression test for #80

8cc2b0f did indeed fix the problem.

closes #80

Author: pschichtel

core/src/test/java/tel/schich/javacan/test/RawCanSocketTest.java

@@ -31,6 +31,7 @@
 import tel.schich.javacan.RawReceiveMessageHeaderBuffer;
 import tel.schich.javacan.platform.linux.LinuxNativeOperationException;
 
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.time.Duration;
 import java.time.Instant;
@@ -347,4 +348,11 @@ void testReceiveHeaders() throws Exception {
             assertEquals(Instant.now().getEpochSecond(), messageHeaderBuffer.getSoftwareTimestamp().getEpochSecond());
         }
     }
+
+    @Test
+    public void repeatedCloseShouldDoNothing() throws IOException {
+        final RawCanChannel socket = CanChannels.newRawChannel();
+        socket.close();
+        socket.close();
+    }
 }

epoll/src/test/java/tel/schich/javacan/test/select/EPollSelectorTest.java

@@ -138,4 +138,11 @@ private static SelectorRegistration<UnixFileDescriptor, RawCanChannel> configure
 
         return registration;
     }
+
+    @Test
+    public void repeatedCloseShouldDoNothing() throws IOException {
+        EPollSelector selector = EPollSelector.open();
+        selector.close();
+        selector.close();
+    }
 }