File: add validation for path uniqueness

Author: kkoehn

app/models/code_ocean/file.rb

@@ -60,6 +60,8 @@ class File < ApplicationRecord
     validates :weight, absence: true, unless: :teacher_defined_assessment?
     validates :file, presence: true if :context.is_a?(Submission)
     validates :context_type, inclusion: {in: ALLOWED_CONTEXT_TYPES}
+    validates :path, uniqueness: {scope: %I[name file_type context_id context_type role]}
+
     # xml_id_path must be unique within the scope of an exercise.
     # Initially, it may match the record’s id (set while exporting),
     # but it can later diverge as long as uniqueness is preserved.

spec/models/code_ocean/file_spec.rb

@@ -137,4 +137,18 @@
       end
     end
   end
+
+  context 'when a file with same attributes (path, name file_type context_id context_type role) already exists' do
+    before do
+      create(:file, name: 'static', context: exercise)
+      file.validate
+    end
+
+    let(:exercise) { create(:dummy) }
+    let(:file) { build(:file, name: 'static', context: exercise) }
+
+    it 'has an error for path' do
+      expect(file.errors[:path]).to be_present
+    end
+  end
 end

spec/services/proforma_service/convert_task_to_exercise_spec.rb

@@ -346,7 +346,7 @@
           ProformaXML::TaskFile.new(
             id: 'ms-file-2',
             content: 'content',
-            filename: 'filename.txt',
+            filename: 'filename2.txt',
             used_by_grader: 'used_by_grader',
             visible: 'yes',
             usage_by_lms: 'display',
@@ -456,7 +456,7 @@
           ProformaXML::TaskFile.new(
             id: 'test_file_id2',
             content: 'testfile-content',
-            filename: 'testfile.txt',
+            filename: 'testfile2.txt',
             used_by_grader: 'yes',
             visible: 'no',
             usage_by_lms: 'display',