should be it

external/duckdb/test/sql/window/test_scalar_window.test

@@ -0,0 +1,44 @@
+# name: test/sql/window/test_scalar_window.test
+# description: Most scalar window functions
+# group: [window]
+
+statement ok
+PRAGMA enable_verification
+
+# test scalar window functions
+query I
+SELECT row_number() OVER ()
+----
+1
+
+query R
+SELECT avg(42) OVER ()
+----
+42.000000
+
+# window on non-aggregate function
+statement error
+SELECT concat() OVER ()
+----
+<REGEX>:.*Catalog Error.*concat is not an aggregate function.*
+
+statement error
+SELECT nonexistingfunction() OVER ()
+----
+<REGEX>:.*Catalog Error.*nonexistingfunction does not exist.*
+
+# nested window functions are not allowed
+statement error
+SELECT avg(row_number() over ()) over ()
+----
+<REGEX>:.*Binder Error.*window function calls cannot be nested.*
+
+statement error
+SELECT avg(42) over (partition by row_number() over ())
+----
+<REGEX>:.*Parser Error.*window functions are not allowed.*
+
+statement error
+SELECT avg(42) over (order by row_number() over ())
+----
+<REGEX>:.*Parser Error.*window functions are not allowed.*