diff --git a/testdata/small.dbsnp.rod b/testdata/small.dbsnp.rod
new file mode 100644
index 000000000..d0ed14d83
--- /dev/null
+++ b/testdata/small.dbsnp.rod
@@ -0,0 +1,100 @@
+585	1	433	433	rs56289060	0	+	-	-	-/C	genomic	insertion	unknown	0	0	unknown	between	1
+585	1	491	492	rs55998931	0	+	C	C	C/T	genomic	single	unknown	0	0	unknown	exact	1
+585	1	518	519	rs62636508	0	+	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	1
+585	1	582	583	rs58108140	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	1
+585	1	690	691	rs10218492	0	+	G	G	A/G	genomic	single	by-cluster	0	0	unknown	exact	1
+585	1	766	767	rs10218493	0	+	G	G	A/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	789	790	rs10218527	0	+	A	A	A/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	800	801	rs28853987	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	876	877	rs28484712	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	884	885	rs28775022	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	884	885	rs62636509	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	943	944	rs10218495	0	+	G	G	G/T	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1016	1017	rs62635278	0	+	A	A	A/C	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1029	1030	rs62635279	0	+	C	C	A/C	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1271	1272	rs9803797	0	+	A	A	A/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1319	1320	rs2758124	0	-	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1332	1333	rs3950659	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1370	1371	rs3877545	0	-	A	A	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1404	1405	rs2758123	0	-	A	A	A/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1427	1428	rs2691333	0	-	G	G	A/C	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1468	1469	rs62162368	0	-	A	A	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1539	1540	rs4030196	0	-	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1554	1555	rs2363296	0	-	A	A	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1591	1592	rs4592209	0	+	T	T	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1643	1644	rs61427470	0	-	C	C	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1643	1644	rs62162367	0	-	C	C	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1649	1650	rs57905273	0	-	T	T	-/A	genomic	deletion	unknown	0	0	unknown	exact	3
+585	1	1665	1666	rs62162366	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1730	1731	rs11510383	0	-	C	C	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1757	1758	rs4030194	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1783	1784	rs57442816	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1808	1809	rs4849250	0	-	C	C	A/G	genomic	single	by-2hit-2allele	0	0	unknown	exact	3
+585	1	1809	1810	rs7564627	0	-	G	G	C/T	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1823	1824	rs2981848	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1825	1826	rs2462500	0	-	G	G	A/C	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1832	1833	rs7357973	0	-	A	A	C/T	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1863	1864	rs62028714	0	+	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1911	1912	rs7357889	0	-	C	C	C/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	1936	1937	rs11510263	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1936	1937	rs62162365	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	1983	1984	rs7357887	0	-	C	C	G/T	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	2032	2033	rs2974776	0	+	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2060	2061	rs3871692	0	-	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2060	2061	rs62635282	0	+	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2065	2066	rs3871693	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2076	2077	rs2441649	0	-	C	C	C/G	genomic	single	by-submitter	0	0	unknown	exact	3
+585	1	2090	2091	rs7340201	0	-	G	G	C/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	2106	2107	rs11897134	0	-	C	C	A/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	2127	2128	rs2475482	0	-	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2154	2155	rs7340200	0	-	G	G	C/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	2168	2169	rs2981847	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2195	2196	rs2981846	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2245	2246	rs62635283	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2289	2290	rs28491605	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2295	2296	rs2475481	0	-	A	A	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2342	2343	rs62028715	0	+	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2351	2352	rs62028716	0	+	G	G	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2368	2369	rs2441647	0	-	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2379	2380	rs3950657	0	-	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2395	2396	rs62028717	0	+	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2469	2470	rs2974781	0	+	C	C	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2634	2635	rs11510117	0	+	A	A	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2636	2637	rs11510118	0	+	G	G	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2642	2643	rs2949418	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2645	2646	rs62635284	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2655	2656	rs11510119	0	+	T	T	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2669	2670	rs62635285	0	+	C	C	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2810	2811	rs2462499	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2886	2887	rs2462498	0	-	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2978	2979	rs62635286	0	+	T	T	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	2980	2981	rs62028691	0	-	A	A	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3000	3001	rs12239753	0	+	T	T	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3016	3017	rs2691331	0	-	A	A	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3020	3021	rs12239425	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3022	3023	rs12239277	0	+	A	A	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3040	3041	rs62028689	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3164	3165	rs2691330	0	-	C	C	A/C/G/T	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	3164	3165	rs28434453	0	-	C	C	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3164	3165	rs28532600	0	-	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3189	3190	rs2691329	0	-	G	G	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3223	3224	rs4951865	0	+	G	G	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3262	3263	rs4951866	0	+	T	T	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3286	3287	rs4951867	0	+	A	A	A/G	genomic	single	by-cluster	0	0	unknown	exact	3
+585	1	3321	3322	rs2747970	0	-	C	C	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3335	3336	rs2592733	0	-	T	T	A/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3354	3355	rs28455646	0	-	C	C	C/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3370	3371	rs28461966	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3370	3371	rs4951868	0	+	T	T	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3419	3420	rs2981841	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3475	3476	rs4951869	0	+	T	T	A/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3526	3527	rs2974786	0	+	T	T	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3529	3530	rs7536480	0	+	C	C	C/T	genomic	single	by-cluster,by-2hit-2allele	0	0	unknown	exact	3
+585	1	3530	3531	rs2691328	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3546	3547	rs4951870	0	+	C	C	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3591	3592	rs2691327	0	-	T	T	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3612	3613	rs2691326	0	-	C	C	A/G	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3638	3639	rs2691325	0	-	G	G	C/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3661	3662	rs7523129	0	+	T	T	G/T	genomic	single	by-cluster,by-2hit-2allele	0	0	unknown	exact	3
+585	1	3675	3676	rs28719485	0	+	T	T	G/T	genomic	single	unknown	0	0	unknown	exact	3
+585	1	3675	3676	rs7166048	0	-	T	T	A/C	genomic	single	by-cluster	0	0	unknown	exact	3