diff --git a/expected/hypopg.out b/expected/hypopg.out
index c735a1e..5e98da8 100644
--- a/expected/hypopg.out
+++ b/expected/hypopg.out
@@ -1,4 +1,16 @@
 -- SETUP
+CREATE OR REPLACE FUNCTION do_explain(stmt text) RETURNS table(a text) AS
+$_$
+DECLARE
+    ret text;
+BEGIN
+    FOR ret IN EXECUTE format('EXPLAIN (FORMAT text) %s', stmt) LOOP
+        a := ret;
+        RETURN next ;
+    END LOOP;
+END;
+$_$
+LANGUAGE plpgsql;
 CREATE EXTENSION hypopg;
 CREATE TABLE hypo (id integer, val text);
 INSERT INTO hypo SELECT i, 'line ' || i
@@ -20,3 +32,90 @@ SELECT nspname, relname, amname FROM public.hypopg_list_indexes();
  public  | hypo    | btree
 (1 row)
 
+-- Should use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo WHERE id = 1') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+ count 
+-------
+     1
+(1 row)
+
+-- Should use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo ORDER BY id') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+ count 
+-------
+     1
+(1 row)
+
+-- Should not use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+ count 
+-------
+     0
+(1 row)
+
+-- Add predicate index
+SELECT COUNT(*) AS nb
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WHERE id < 5');
+ nb 
+----
+  1
+(1 row)
+
+-- This specific index should be used
+WITH ind AS (
+    SELECT indexrelid, row_number() OVER (ORDER BY indexrelid) AS num
+    FROM public.hypopg()
+),
+regexp AS (
+    SELECT regexp_replace(e, '.*<(\d+)>.*', E'\\1', 'g') AS r
+    FROM do_explain('SELECT * FROM hypo WHERE id < 3') AS e
+)
+SELECT num
+FROM ind
+JOIN regexp ON ind.indexrelid::text = regexp.r;
+ num 
+-----
+   2
+(1 row)
+
+-- Specify fillfactor
+SELECT COUNT(*) AS NB
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 10)');
+ nb 
+----
+  1
+(1 row)
+
+-- Specify an incorrect fillfactor
+SELECT COUNT(*) AS NB
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 1)');
+ERROR:  value 1 out of bounds for option "fillfactor"
+DETAIL:  Valid values are between "10" and "100".
+-- Index size estimation
+SELECT pg_size_pretty(hypopg_relation_size(indexrelid))
+FROM hypopg()
+ORDER BY indexrelid;
+ pg_size_pretty 
+----------------
+ 2544 kB
+ 8192 bytes
+ 4120 kB
+(3 rows)
+
+-- Remove one hypothetical index
+SELECT hypopg_drop_index(indexrelid) FROM hypopg() ORDER BY indexrelid LIMIT 1;
+ hypopg_drop_index 
+-------------------
+ t
+(1 row)
+
+-- Remove all the hypothetical indexes
+SELECT hypopg_reset();
+ hypopg_reset 
+--------------
+ 
+(1 row)
+
diff --git a/test/sql/hypopg.sql b/test/sql/hypopg.sql
index e72005b..b28cd5b 100644
--- a/test/sql/hypopg.sql
+++ b/test/sql/hypopg.sql
@@ -1,4 +1,17 @@
 -- SETUP
+CREATE OR REPLACE FUNCTION do_explain(stmt text) RETURNS table(a text) AS
+$_$
+DECLARE
+    ret text;
+BEGIN
+    FOR ret IN EXECUTE format('EXPLAIN (FORMAT text) %s', stmt) LOOP
+        a := ret;
+        RETURN next ;
+    END LOOP;
+END;
+$_$
+LANGUAGE plpgsql;
+
 CREATE EXTENSION hypopg;
 
 CREATE TABLE hypo (id integer, val text);
@@ -13,3 +26,52 @@ SELECT COUNT(*) AS nb
 FROM public.hypopg_create_index('SELECT 1;CREATE INDEX ON hypo(id); SELECT 2');
 
 SELECT nspname, relname, amname FROM public.hypopg_list_indexes();
+
+-- Should use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo WHERE id = 1') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+
+-- Should use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo ORDER BY id') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+
+-- Should not use hypothetical index
+SELECT COUNT(*) FROM do_explain('SELECT * FROM hypo') e
+WHERE e ~ 'Index.*<\d+>btree_hypo.*';
+
+-- Add predicate index
+SELECT COUNT(*) AS nb
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WHERE id < 5');
+
+-- This specific index should be used
+WITH ind AS (
+    SELECT indexrelid, row_number() OVER (ORDER BY indexrelid) AS num
+    FROM public.hypopg()
+),
+regexp AS (
+    SELECT regexp_replace(e, '.*<(\d+)>.*', E'\\1', 'g') AS r
+    FROM do_explain('SELECT * FROM hypo WHERE id < 3') AS e
+)
+
+SELECT num
+FROM ind
+JOIN regexp ON ind.indexrelid::text = regexp.r;
+
+-- Specify fillfactor
+SELECT COUNT(*) AS NB
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 10)');
+
+-- Specify an incorrect fillfactor
+SELECT COUNT(*) AS NB
+FROM public.hypopg_create_index('CREATE INDEX ON hypo(id) WITH (fillfactor = 1)');
+
+-- Index size estimation
+SELECT pg_size_pretty(hypopg_relation_size(indexrelid))
+FROM hypopg()
+ORDER BY indexrelid;
+
+-- Remove one hypothetical index
+SELECT hypopg_drop_index(indexrelid) FROM hypopg() ORDER BY indexrelid LIMIT 1;
+
+-- Remove all the hypothetical indexes
+SELECT hypopg_reset();