should be it

external/duckdb/tools/juliapkg/test/test_replacement_scan.jl

@@ -0,0 +1,72 @@
+# test_replacement_scan.jl
+
+function RangeReplacementScan(info)
+    table_name = DuckDB.get_table_name(info)
+    number = tryparse(Int64, table_name)
+    if number === nothing
+        return
+    end
+    DuckDB.set_function_name(info, "range")
+    DuckDB.add_function_parameter(info, DuckDB.create_value(number))
+    return
+end
+
+@testset "Test replacement scans" begin
+    con = DBInterface.connect(DuckDB.DB)
+
+    # add a replacement scan that turns any number provided as a table name into range(X)
+    DuckDB.add_replacement_scan!(con, RangeReplacementScan, nothing)
+
+    df = DataFrame(DBInterface.execute(con, "SELECT * FROM \"2\" tbl(a)"))
+    @test df.a == [0, 1]
+
+    # this still fails
+    @test_throws DuckDB.QueryException DBInterface.execute(con, "SELECT * FROM nonexistant")
+
+    DBInterface.close!(con)
+end
+
+function RepeatReplacementScan(info)
+    table_name = DuckDB.get_table_name(info)
+    splits = split(table_name, "*")
+    if size(splits, 1) != 2
+        return
+    end
+    number = tryparse(Int64, splits[2])
+    if number === nothing
+        return
+    end
+    DuckDB.set_function_name(info, "repeat")
+    DuckDB.add_function_parameter(info, DuckDB.create_value(splits[1]))
+    DuckDB.add_function_parameter(info, DuckDB.create_value(number))
+    return
+end
+
+@testset "Test string replacement scans" begin
+    con = DBInterface.connect(DuckDB.DB)
+
+    # add a replacement scan that turns any number provided as a table name into range(X)
+    DuckDB.add_replacement_scan!(con, RepeatReplacementScan, nothing)
+
+    df = DataFrame(DBInterface.execute(con, "SELECT * FROM \"hello*2\" tbl(a)"))
+    @test df.a == ["hello", "hello"]
+
+    # this still fails
+    @test_throws DuckDB.QueryException DBInterface.execute(con, "SELECT * FROM nonexistant")
+
+    DBInterface.close!(con)
+end
+
+function ErrorReplacementScan(info)
+    throw("replacement scan eek")
+end
+
+@testset "Test error replacement scans" begin
+    con = DBInterface.connect(DuckDB.DB)
+
+    DuckDB.add_replacement_scan!(con, ErrorReplacementScan, nothing)
+
+    @test_throws DuckDB.QueryException DBInterface.execute(con, "SELECT * FROM nonexistant")
+
+    DBInterface.close!(con)
+end