fix (#840) `Server error saving [...] TB Diagnostics

forms opened from admin site`

Author: JonathanWillitts

CHANGES

@@ -1,6 +1,13 @@
 Changes
 +++++++
 
+unreleased
+------
+- fix `Server error saving [...] TB Diagnostics forms opened from
+  admin site` (#840)
+- # TODO: bump to effect-form-validators 1.0.0 (once released)
+
+
 1.0.0
 ------
 - fix issues where addition of some unscheduled visits could result in

effect_subject/forms/tb_diagnostics_form.py

@@ -26,14 +26,14 @@ class TbDiagnosticsFormValidator(
 ):
     def clean(self):
         self.validate_study_day_with_datetime(
-            subject_identifier=self.cleaned_data.get("subject_visit").subject_identifier,
+            subject_identifier=self.related_visit.subject_identifier,
             study_day=self.cleaned_data.get("day_blood_taken"),
             compare_date=self.cleaned_data.get("blood_taken_date"),
             study_day_field="day_blood_taken",
         )
 
         self.validate_study_day_with_datetime(
-            subject_identifier=self.cleaned_data.get("subject_visit").subject_identifier,
+            subject_identifier=self.related_visit.subject_identifier,
             study_day=self.cleaned_data.get("day_biopsy_taken"),
             compare_date=self.cleaned_data.get("biopsy_date"),
             study_day_field="day_biopsy_taken",