Name core tests consistently

Now, given a concept xyz,
* the main test file is called test_xyz.cc
* the executable is called test_xyz, and
* the ctest test is called text_xyz.

server/core/test/test_session.cc

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+/**
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date         Who                 Description
+ * 11-09-2014   Martin Brampton     Initial implementation
+ *
+ * @endverbatim
+ */
+
+// To ensure that ss_info_assert asserts also when builing in non-debug mode.
+#if !defined(SS_DEBUG)
+#define SS_DEBUG
+#endif
+#if defined(NDEBUG)
+#undef NDEBUG
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <maxscale/poll.h>
+#include <dcb.h>
+
+/**
+ * test1    Allocate a service and do lots of other things
+ *
+  */
+
+static int
+test1()
+{
+    DCB     *dcb;
+    int     result;
+
+    /* Poll tests */
+    ss_dfprintf(stderr,
+                "testpoll : Initialise the polling system.");
+    poll_init();
+    ss_dfprintf(stderr, "\t..done\nAdd a DCB");
+    dcb = dcb_alloc(DCB_ROLE_SERVICE_LISTENER);
+    dcb->fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    poll_add_dcb(dcb);
+    poll_remove_dcb(dcb);
+    poll_add_dcb(dcb);
+    ss_dfprintf(stderr, "\t..done\nStart wait for events.");
+    sleep(10);
+    poll_shutdown();
+    ss_dfprintf(stderr, "\t..done\nTidy up.");
+    dcb_close(dcb);
+    ss_dfprintf(stderr, "\t..done\n");
+
+    return 0;
+
+}
+
+int main(int argc, char **argv)
+{
+    int result = 0;
+
+    result += test1();
+
+    exit(result);
+}
+