Add tests for UserController, Accounts, Generators.

test/support/fixtures/accounts_fixtures.ex

@@ -0,0 +1,26 @@
+defmodule LinkShortener.AccountsFixtures do
+  @moduledoc """
+  This module defines test helpers for creating
+  entities via the `LinkShortener.Accounts` context.
+  """
+
+  @doc """
+  Generate a unique user email.
+  """
+  def unique_user_email, do: "some email#{System.unique_integer([:positive])}"
+
+  @doc """
+  Generate a new user.
+  """
+  def user_fixture(attrs \\ %{}) do
+    {:ok, user} =
+      attrs
+      |> Enum.into(%{
+        email: unique_user_email(),
+        password: "some encrypted_password"
+      })
+      |> LinkShortener.Accounts.create_user()
+
+    LinkShortener.Accounts.get_user!(user.id)
+  end
+end