Add generators for user, author and author_roles for tests.

test/decentralised_book_index/metadata/book_test.exs

@@ -5,22 +5,14 @@ defmodule DecentralisedBookIndex.Metadata.BookTest do
 
   describe "books and registries relationship" do
     test "a new book get new registry by default" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       assert {:ok, book} = Metadata.create_book("Book", "1234567890", "An description", author_roles)
       assert book.book_editions_registry_id != nil
     end
 
     test "a new book belongs to a registry if specified" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       assert {:ok, registry} = Metadata.create_book_editions_registry()
       assert {:ok, book} = Metadata.create_book("Book", "1234567890", "An description", author_roles, registry.id)
@@ -28,11 +20,7 @@ defmodule DecentralisedBookIndex.Metadata.BookTest do
     end
 
     test "a new book to a registry via a related book record" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       {:ok, related_book} = Metadata.create_book("Book", "1234567890", "An description", author_roles)
 
@@ -43,11 +31,7 @@ defmodule DecentralisedBookIndex.Metadata.BookTest do
     end
 
     test "a new book to a registry via a empty related book record" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       assert {:error, _} =
         Metadata.add_book_to_related_editions_registry("Book2", "1234567891", "An description2", author_roles, nil)
@@ -56,11 +40,7 @@ defmodule DecentralisedBookIndex.Metadata.BookTest do
 
   describe "books alternatives names" do
     test "new book has no alternatives names" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       {:ok, book} = Metadata.create_book("Book", "1234567890", "An description", author_roles)
       assert {:ok, alternatives_names} = Metadata.get_book_alternative_editions(book)
@@ -68,11 +48,7 @@ defmodule DecentralisedBookIndex.Metadata.BookTest do
     end
 
     test "book has related book so they has one alternative name" do
-      {:ok, author} = Metadata.create_author("Author", "An description")
-
-      author_roles = [
-        %{order: 1, author_id: author.id, role: ""}
-      ]
+      author_roles = author_roles()
 
       {:ok, related_book} = Metadata.create_book("Book", "1234567890", "An description", author_roles)