Added end2end test case

Added end2end test case for exercising code from attention event to isolator.

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: I5bde1c50e4b70e284e99e71bb69d55041310c0d0
diff --git a/test/end2end/main.cpp b/test/end2end/main.cpp
new file mode 100644
index 0000000..3540f6d
--- /dev/null
+++ b/test/end2end/main.cpp
@@ -0,0 +1,18 @@
+#include <libpdbg.h>
+
+#include <attn/attn_handler.hpp>
+
+// The attnHandler() function is called when the an attention GPIO event is
+// triggered. We call it here directly to simulatea a GPIO event.
+int main()
+{
+    int rc = 0; // return code
+
+    // initialize pdbg targets
+    pdbg_targets_init(nullptr);
+
+    // exercise attention gpio event path
+    attn::attnHandler(false);
+
+    return rc;
+}