Make csv= specs actually test something

Recent changes rewired specs to test import by setting `csv_data` instead of
`csv` to isolate what's being tested, but that left `csv=` largely being untested.

Jira-Issue: MAV-6063

Author: misaka

spec/fixtures/files/cohort_import/valid_with_bom.csv

@@ -0,0 +1,2 @@
+CHILD_FIRST_NAME,CHILD_LAST_NAME,CHILD_DATE_OF_BIRTH,CHILD_POSTCODE,CHILD_SCHOOL_URN
+Jennifer,Clarke,2010-01-01,SW1A 1AA,123456

spec/fixtures/files/immunisation_import/point_of_care/valid_with_bom.csv

@@ -0,0 +1,2 @@
+ORGANISATION_CODE,SCHOOL_URN,SCHOOL_NAME,NHS_NUMBER,PERSON_FORENAME,PERSON_SURNAME,PERSON_DOB,PERSON_GENDER_CODE,PERSON_POSTCODE,VACCINATED,DATE_OF_VACCINATION,PROGRAMME,VACCINE_GIVEN,BATCH_NUMBER,BATCH_EXPIRY_DATE,ANATOMICAL_SITE,PERFORMING_PROFESSIONAL_FORENAME,PERFORMING_PROFESSIONAL_SURNAME,REASON_NOT_VACCINATED,CONSENT_TYPE,LOCAL_PATIENT_ID,LOCAL_PATIENT_ID_URI
+R1L,120026,shaftesbury junior school ,7420180008,Chyna,Pickle,20120912,Not Specified,LE3 2DA,Yes,20250514,Flu,,123013325,20220730,Left Buttock,Vaccinator1,Name1,,Parental Consent,LocalPatient1,www.LocalPatient1

spec/models/class_import_spec.rb

@@ -48,7 +48,9 @@
   let(:session) { create(:session, location:, programmes:, team:) }
 
   let(:file) { "valid.csv" }
-  let(:csv_data) { file_fixture("class_import/#{file}").read }
+  let(:csv_source) { file_fixture("class_import/#{file}") }
+  let(:csv_data) { csv_source.read }
+  # Used by shared examples in CSVImportable to test setting csv from an uploaded file
   let(:uploaded_csv_file) { nil }
 
   # This is used by validation tests in the CSFVImportable shared specs.
@@ -61,18 +63,6 @@
 
     before { parse_rows! }
 
-    describe "with a BOM" do
-      let(:csv_data) { nil }
-      let(:uploaded_csv_file) do
-        fixture_file_upload("class_import/#{file}", filename: file)
-      end
-      let(:file) { "valid_with_bom.csv" }
-
-      it "removes the BOM" do
-        expect(class_import).to be_valid
-      end
-    end
-
     describe "with invalid fields" do
       let(:file) { "invalid_fields.csv" }
 

spec/models/cohort_import_spec.rb

@@ -42,7 +42,9 @@
   let(:team) { create(:team, programmes:) }
 
   let(:file) { "valid.csv" }
-  let(:csv_data) { file_fixture("cohort_import/#{file}").read }
+  let(:csv_source) { file_fixture("cohort_import/#{file}") }
+  let(:csv_data) { csv_source.read }
+  # Used by shared examples in CSVImportable to test setting csv from an uploaded file
   let(:uploaded_csv_file) { nil }
 
   # Ensure location URN matches the URN in our fixture files

spec/models/immunisation_import_spec.rb

@@ -35,7 +35,13 @@
 
 describe ImmunisationImport do
   subject(:immunisation_import) do
-    create(:immunisation_import, team:, csv_data:, uploaded_by:)
+    create(
+      :immunisation_import,
+      team:,
+      csv_data:,
+      uploaded_by:,
+      uploaded_csv_file:
+    )
   end
 
   before do
@@ -56,7 +62,9 @@
   let(:school) { create(:gias_school, urn: "123456") }
 
   let(:file) { "valid_flu.csv" }
-  let(:csv_data) { file_fixture("immunisation_import/#{type}/#{file}").read }
+  let(:csv_source) { file_fixture("immunisation_import/#{type}/#{file}") }
+  let(:csv_data) { csv_source.read }
+  # Used by shared examples in CSVImportable to test setting csv from an uploaded file
   let(:uploaded_csv_file) { nil }
   let(:uploaded_by) { create(:user, team:) }
 

spec/support/shared_examples/a_csv_importable_model.rb

@@ -51,15 +51,26 @@
     end
   end
 
-  # TODO: This needs to set `csv`, it currently doesn't trigger it the way it's
-  #       done here.
   describe "#csv=" do
+    let(:csv_data) { nil }
+    let(:uploaded_csv_file) { fixture_file_upload(csv_source) }
+
     it "sets the data" do
-      expect(subject.csv_data).not_to be_empty
+      expect(subject.csv_data).to eq uploaded_csv_file.read
     end
 
     it "sets the filename" do
-      expect(subject.csv_filename).not_to be_empty
+      expect(subject.csv_filename).to eq uploaded_csv_file.original_filename
+    end
+
+    context "with a payload with a BOM" do
+      # This requires that each test using these shared example have a file with
+      # a BOM in their fixtures directory
+      let(:file) { "valid_with_bom.csv" }
+
+      it "results in a valid import" do
+        expect(subject).to be_valid
+      end
     end
   end