From a3060be40f11fe12e0ebf4f06bcdcb9c450c8433 Mon Sep 17 00:00:00 2001
From: vennyy3 <vendelasoiland@hotmail.com>
Date: Wed, 1 Jul 2026 11:46:36 +0200
Subject: [PATCH] tests for user defined functions

---
 lib/query_processing/src/errors.rs |  2 +-
 py_maplib/tests/test_udfs.py       | 49 +++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/lib/query_processing/src/errors.rs b/lib/query_processing/src/errors.rs
index 9b090c19..463c93b0 100644
--- a/lib/query_processing/src/errors.rs
+++ b/lib/query_processing/src/errors.rs
@@ -31,7 +31,7 @@ pub enum QueryProcessingError {
     ExpectedIntegerArgument(Function),
     #[error("Error parsing literal {0}")]
     ParseLiteralError(RepresentationError),
-    #[error("UDF function error {0}")]
+    #[error("UDF function error: {0}")]
     UDFError(String),
     #[error(
         "Custom function not found: {0}, it is possible to define a function using m.add_udf()"
diff --git a/py_maplib/tests/test_udfs.py b/py_maplib/tests/test_udfs.py
index 24212168..babfee1f 100644
--- a/py_maplib/tests/test_udfs.py
+++ b/py_maplib/tests/test_udfs.py
@@ -1,5 +1,7 @@
 import polars as pl
-from maplib import Model, xsd
+import pytest
+from polars import DataFrame
+from maplib import Model, xsd, RDFType, MaplibException
 
 def f(df: pl.DataFrame) -> pl.Series:
     df = df.with_columns(
@@ -13,6 +15,12 @@ def g(df: pl.DataFrame) -> pl.DataFrame:
     )
     return df
 
+def h(df: DataFrame) -> pl.DataFrame:
+    df = df.with_columns(
+        (pl.col("0") + pl.lit("_suf")).alias("out")
+    )
+    return df
+
 def test_udf_query():
     m = Model()
     m.add_udf("urn:maplib:plusarg", f, xsd.integer)
@@ -49,8 +57,47 @@ def test_udf_query_strings():
     print(result)
     assert result.get_column("found").sort().to_list() == [None, False, False, True]
 
+def test_udf_query_iris():
+    m = Model()
+    m.add_udf("urn:maplib:addsuf", h, RDFType.IRI, [RDFType.IRI])
+    m.reads("""
+            <http://example.org/a> <urn:maplib:hasiri> <http://example.org/abe> .
+            <http://example.org/a> <urn:maplib:hasiri> <http://example.org/abc> .
+            <http://example.org/a> <urn:maplib:hasiri> <http://example.org/abd> .
+        """, "turtle")
+    result = m.query("""
+        SELECT * {
+            ?a <urn:maplib:hasiri> ?s1 .
+            BIND(<urn:maplib:addsuf>(?s1) AS ?suffed)
+        }
+        """)
+    assert result.get_column("suffed").sort().to_list() == ['<http://example.org/abc_suf>', '<http://example.org/abd_suf>', '<http://example.org/abe_suf>']
+
 def test_list_udfs():
     m = Model()
     assert m.list_udfs() == []
     m.add_udf("urn:maplib:myudf", f, xsd.integer)
     assert m.list_udfs() == ["urn:maplib:myudf"]
+
+def test_udf_error_message():
+    m = Model()
+    with pytest.raises(Exception, match="is not callable"):
+        m.add_udf("urn:maplib:test", "test", xsd.boolean, [xsd.string])
+
+def test_udf_wrong_output_type():
+    m = Model()
+    m.add_udf("urn:maplib:findabc", g, xsd.integer, [xsd.string])
+    m.reads("""
+            <http://example.org/a> <urn:maplib:hasstr> "1" .
+            <http://example.org/a> <urn:maplib:hasstr> "ab2" .
+            <http://example.org/b> <urn:maplib:hasstr> "abc" .
+            <http://example.org/b> <urn:maplib:hasstr> 1 .
+        """, "turtle")
+    with pytest.raises(MaplibException) as e:
+        result = m.query("""
+            SELECT * {
+                ?a <urn:maplib:hasstr> ?s1 .
+                BIND(<urn:maplib:findabc>(?s1) AS ?found)
+            }
+            """)
+        assert "did not have the expected type" in e
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