From 5d3ceec7544165702d17cbc161cd447ccf7d6024 Mon Sep 17 00:00:00 2001
From: mrbean-bremen <hansemrbean@googlemail.com>
Date: Mon, 16 Dec 2024 20:27:52 +0100
Subject: [PATCH] Fix check for empty string values

- broke handling of empty type 2 enumerated values
- fixes #147
---
 CHANGES.md                                    |  3 ++
 .../tests/validator/test_iod_validator.py     | 47 +++++++++++++++++++
 dicom_validator/validator/iod_validator.py    |  4 +-
 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 8a15af7..f6e7234 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,9 @@
 # Dicom Validator Release Notes
 The released versions correspond to PyPi releases.
 
+### Fixes
+* fixed handling of empty type 2 enumerated values (see [#147](../../issues/147))
+
 ### Infrastructure
 * update the tests for current version 2024e
 
diff --git a/dicom_validator/tests/validator/test_iod_validator.py b/dicom_validator/tests/validator/test_iod_validator.py
index 53b4395..8a3cdca 100644
--- a/dicom_validator/tests/validator/test_iod_validator.py
+++ b/dicom_validator/tests/validator/test_iod_validator.py
@@ -476,6 +476,53 @@ def test_invalid_enum_value(self, validator):
             "(value: 1, allowed: 8, 9, 10, 11, 12, 13, 14, 15, 16)",
         )
 
+    @pytest.mark.tag_set(
+        {
+            "SOPClassUID": uid.EnhancedXAImageStorage,
+            "PatientName": "XXX",
+            "PatientID": "ZZZ",
+            "ImageType": "DERIVED",
+            "PresentationLUTShape": "",
+        }
+    )
+    def test_empty_type_1_enum_value(self, validator):
+        result = validator.validate()
+
+        # Presentation LUT Shape: incorrect enum value
+        assert has_tag_error(
+            result,
+            "Enhanced XA/XRF Image",
+            "(2050,0020)",
+            "is empty",
+        )
+
+    @pytest.mark.tag_set(
+        {
+            "SOPClassUID": uid.OphthalmicPhotography8BitImageStorage,
+            "PatientName": "XXX",
+            "PatientID": "ZZZ",
+            "PatientEyeMovementCommanded": "",
+            "PupilDilated": "",
+        }
+    )
+    def test_empty_type_2_enum_value(self, validator):
+        # regression test for #147
+        result = validator.validate()
+
+        assert not has_tag_error(
+            result,
+            "Ophthalmic Photography Acquisition Parameters",
+            "(0022,0005)",
+            "value is not allowed",
+        )
+
+        assert not has_tag_error(
+            result,
+            "Ophthalmic Photography Acquisition Parameters",
+            "(0022,000D)",
+            "value is not allowed",
+        )
+
     @pytest.mark.tag_set(
         {
             "SOPClassUID": uid.MRImageStorage,
diff --git a/dicom_validator/validator/iod_validator.py b/dicom_validator/validator/iod_validator.py
index 607a637..3719359 100644
--- a/dicom_validator/validator/iod_validator.py
+++ b/dicom_validator/validator/iod_validator.py
@@ -391,9 +391,9 @@ def _validate_attribute(self, tag_id, attribute):
             value = self._dataset_stack[-1].dataset[tag_id].value
             vr = self._dataset_stack[-1].dataset[tag_id].VR
             if value_required:
-                if value is None or isinstance(value, Sequence) and not value:
+                if value is None or isinstance(value, (Sequence, str)) and not value:
                     error_kind = "empty"
-            if value is not None:
+            if value is not None and (not isinstance(value, str) or value):
                 if not isinstance(value, MultiValue):
                     value = [value]
                 for i, v in enumerate(value):