Updated NEWS and tests README

test/README

@@ -6,6 +6,14 @@ Example, to add a test for CDB_Something function, you'd add:
  - CDB_SomethingTest.sql
  - CDB_SomethingTest_expect
 
+In case you need multiple expects of a test for different versions you have
+to add .pg$(VERSION) at the end of the file.
+
+For example if you want an expect file for PG11 you need to have two expect files:
+
+  - CDB_SomethingTest_expect
+  - CDB_SomethingTest_expect.pg11
+
 To easy the generation of the expected file you can initially omit it,
 then run "make -C .. installcheck" from the top-level dir and copy
 ../results/test/CDB_SomethingTest.out to CDB_SomethingTest_expect chopping