Only create/drop extensions in tests if needed

spec/pg/decoder_spec.cr

@@ -40,19 +40,19 @@ describe PG::Decoders do
 
   it "citext" do
     begin
-      PG_DB.exec("CREATE EXTENSION \"citext\"")
+      PG_DB.exec("CREATE EXTENSION IF NOT EXISTS \"citext\"")
       with_connection do |conn| # fresh connection so decoders are evaluated
         value = conn.query_one "select 'abc'::citext", &.read
         value.should eq("abc")
       end
     ensure
-      PG_DB.exec("DROP EXTENSION \"citext\"")
+      PG_DB.exec("DROP EXTENSION IF EXISTS \"citext\"")
     end
   end
 
   it "hstore" do
     begin
-      PG_DB.exec("CREATE EXTENSION \"hstore\"")
+      PG_DB.exec("CREATE EXTENSION IF NOT EXISTS \"hstore\"")
       with_connection do |conn| # fresh connection so decoders are evaluated
         value = conn.query_one "select 'foo=>bar,baz=>42'::hstore", &.read
         value.should eq({"foo" => "bar", "baz" => "42"})
@@ -67,7 +67,7 @@ describe PG::Decoders do
         value.should eq(nil)
       end
     ensure
-      PG_DB.exec("DROP EXTENSION \"hstore\"")
+      PG_DB.exec("DROP EXTENSION IF EXISTS \"hstore\"")
     end
   end
 

spec/pg/encoder_spec.cr

@@ -3,7 +3,7 @@ require "../spec_helper"
 private def test_insert_and_read(datatype, value, extension = nil, file = __FILE__, line = __LINE__)
   it "inserts #{datatype}", file, line do
     begin
-      PG_DB.exec "create extension \"#{extension}\"" if extension
+      PG_DB.exec "create extension if not exists \"#{extension}\"" if extension
 
       with_connection do |conn|
         conn.exec "drop table if exists test_table"
@@ -19,7 +19,7 @@ private def test_insert_and_read(datatype, value, extension = nil, file = __FILE
         actual_value.should eq(value)
       end
     ensure
-      PG_DB.exec "drop extension \"#{extension}\" cascade" if extension
+      PG_DB.exec "drop extension if exists \"#{extension}\" cascade" if extension
     end
   end
 end