@SuppressWarnings("unchecked")
@Test 
public void testInternalCloseCoverage() throws SQLException {

	this.testClass.connectionTrackingDisabled = false;
	this.testClass.finalizableRefs = new MapMaker().makeMap();
	this.testClass.finalizableRefs.put(this.testClass.connection, createNiceMock(Reference.class));
	this.testClass.internalClose();
	assertTrue(this.testClass.finalizableRefs.isEmpty());
	
	this.testClass.connectionTrackingDisabled = false;
	this.testClass.finalizableRefs = null;  // should never happen
	this.testClass.internalClose();
	
	// should not fail if connection was somehow destroy. 
	this.testClass.connection = null;
	this.testClass.internalClose();
	
}