Add factory for MergeRequestDiff and MergeRequestDiffFile

spec/factories/merge_request_diff_files.rb

+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :merge_request_diff_file do
+    association :merge_request_diff
+
+    relative_order 0
+    new_file true
+    renamed_file false
+    deleted_file false
+    too_large false
+    a_mode 0
+    b_mode 100644
+    new_path 'foo'
+    old_path 'foo'
+    diff ''
+    binary false
+
+    trait :new_file do
+      relative_order 0
+      new_file true
+      renamed_file false
+      deleted_file false
+      too_large false
+      a_mode 0
+      b_mode 100644
+      new_path 'foo'
+      old_path 'foo'
+      diff ''
+      binary false
+    end
+
+    trait :renamed_file do
+      relative_order 662
+      new_file false
+      renamed_file true
+      deleted_file false
+      too_large false
+      a_mode 100644
+      b_mode 100644
+      new_path 'bar'
+      old_path 'baz'
+      diff ''
+      binary false
+    end
+  end
+end

spec/factories/merge_request_diffs.rb

+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :merge_request_diff do
+    association :merge_request
+    state :collected
+    commits_count 1
+
+    base_commit_sha { Digest::SHA1.hexdigest(SecureRandom.hex) }
+    head_commit_sha { Digest::SHA1.hexdigest(SecureRandom.hex) }
+    start_commit_sha { Digest::SHA1.hexdigest(SecureRandom.hex) }
+  end
+end