diff --git a/htsinfer/get_read_orientation.py b/htsinfer/get_read_orientation.py
index c7dd1ff..a9ccd36 100644
--- a/htsinfer/get_read_orientation.py
+++ b/htsinfer/get_read_orientation.py
@@ -77,7 +77,7 @@ def evaluate(self) -> ResultsOrientation:
 
         if not self.mapping.mapped \
                 and self.library_source.file_1.short_name is not None \
-                and self.library_source.file_2.short_name is not None:
+                or self.library_source.file_2.short_name is not None:
             self.mapping.evaluate()
         else:
             LOGGER.warning(
diff --git a/tests/test_get_library_type.py b/tests/test_get_library_type.py
index 8555694..738840a 100644
--- a/tests/test_get_library_type.py
+++ b/tests/test_get_library_type.py
@@ -13,7 +13,9 @@
     GetFastqType,
 )
 from htsinfer.models import (
+    ResultsSource,
     ResultsType,
+    Source,
     SeqIdFormats,
     StatesType,
     StatesTypeRelationship,
@@ -147,6 +149,10 @@ def test_evaluate_mate_relationship_not_available(self, tmpdir):
         CONFIG.args.path_1_processed = FILE_IDS_NOT_MATCH_1
         CONFIG.args.path_2_processed = FILE_MATE_2
         CONFIG.args.t_file_processed = FILE_TRANSCRIPTS
+        CONFIG.results.library_source = ResultsSource(
+            file_1=Source(short_name="hsapiens", taxon_id=9606),
+            file_2=Source(short_name="hsapiens", taxon_id=9606),
+        )
         CONFIG.args.tmp_dir = tmpdir
         MAPPING.paths = (FILE_IDS_NOT_MATCH_1, FILE_MATE_2)
         MAPPING.transcripts_file = FILE_TRANSCRIPTS
@@ -167,6 +173,10 @@ def test_evaluate_split_mates_not_matching_ids(self, tmpdir):
         """
         CONFIG.args.path_1_processed = FILE_IDS_NOT_MATCH_1
         CONFIG.args.path_2_processed = FILE_IDS_NOT_MATCH_2
+        CONFIG.results.library_source = ResultsSource(
+            file_1=Source(short_name="hsapiens", taxon_id=9606),
+            file_2=Source(short_name="hsapiens", taxon_id=9606),
+        )
         CONFIG.args.tmp_dir = tmpdir
         MAPPING.paths = (FILE_IDS_NOT_MATCH_1, FILE_IDS_NOT_MATCH_2)
         MAPPING.tmp_dir = tmpdir