adding utils test

src/pg/test/sql/40_observatory_utility_test.sql

@@ -0,0 +1,50 @@
+SELECT set_config(
+    'search_path',
+    current_setting('search_path') || ',cdb_observatory',
+    false
+) WHERE current_setting('search_path') !~ '(^|,)cdb_observatory(,|$)';
+
+-- OBS_GeomTable
+-- get table with known geometry_id
+-- should give back a table like obs_{hex hash}
+SELECT 
+  cdb_observatory.OBS_GeomTable(
+    CDB_LatLng(40.7128,-74.0059),
+    '"us.census.tiger".census_tract'
+  );
+
+-- get null for unknown geometry_id
+-- should give back null
+SELECT 
+  cdb_observatory.OBS_GeomTable(
+    CDB_LatLng(40.7128,-74.0059),
+    '"us.census.tiger".nonexistant_id'
+  );
+
+-- OBS_GetColumnData
+-- should give back:
+--  colname   | tablename       | aggregate
+-- -----------|-----------------|-----------
+--  geoid     | obs_{hex table} | null
+--  total_pop | obs_{hex table} | sum
+SELECT 
+  (unnest(cdb_observatory.OBS_GetColumnData(
+    '"us.census.tiger".census_tract',
+    Array['"us.census.tiger".census_tract_geoid', '"us.census.acs".B01001001'],
+    '2009 - 2013'
+  ))).*
+ORDER BY 1 ASC;
+
+-- OBS_LookupCensusHuman
+-- should give back: {"\"us.census.acs\".B19083001"}
+SELECT 
+  cdb_observatory.OBS_LookupCensusHuman(
+    Array['gini_index']
+  );
+
+-- OBS_BuildSnapshotQuery
+-- Should give back: SELECT  vals[1] As total_pop, vals[2] As male_pop, vals[3] As female_pop, vals[4] As median_age
+SELECT 
+  cdb_observatory.OBS_BuildSnapshotQuery(
+    Array['total_pop','male_pop','female_pop','median_age']
+  );