Added avg aggregate for vector - closes #51

test/t/008_avg.pl

@@ -0,0 +1,27 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More tests => 4;
+
+# Initialize node
+my $node = get_new_node('node');
+$node->init;
+$node->start;
+
+# Create table
+$node->safe_psql("postgres", "CREATE EXTENSION vector;");
+$node->safe_psql("postgres", "CREATE TABLE tst (v vector(3));");
+$node->safe_psql("postgres",
+    "INSERT INTO tst SELECT ARRAY[1.01 + random(), 2.01 + random(), 3.01 + random()] FROM generate_series(1, 1000000) i;"
+);
+
+# Test avg
+my $avg = $node->safe_psql("postgres", "SELECT AVG(v) FROM tst;");
+like($avg, qr/\[1\.5/);
+like($avg, qr/,2\.5/);
+like($avg, qr/,3\.5/);
+
+# Test explain
+my $explain = $node->safe_psql("postgres", "EXPLAIN SELECT AVG(v) FROM tst;");
+like($explain, qr/Partial Aggregate/);