feat: enhance transaction handling in Repo module

- Updated the `transact/2` function to handle `:ok` return values, allowing for successful transactions without a result.
- Added a new test suite for `Repo.transact/2` to cover various scenarios including successful commits, rollbacks on errors, and nested transactions.

Author: zcesur

lib/algora/repo.ex

@@ -61,8 +61,10 @@ defmodule Algora.Repo do
           end
 
         case result do
+          :ok -> nil
           {:ok, result} -> result
           {:error, reason} -> repo.rollback(reason)
+          error -> repo.rollback(error)
         end
       end,
       opts

test/algora/repo_test.exs

@@ -0,0 +1,148 @@
+defmodule Algora.RepoTest do
+  use Algora.DataCase
+
+  alias Algora.Accounts.User
+  alias Algora.Repo
+
+  describe "transact/2" do
+    test "commits transaction when {:ok, result} is returned" do
+      user = insert(:user)
+      original_email = user.email
+
+      {:ok, result} =
+        Repo.transact(fn _repo ->
+          {:ok, updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          {:ok, updated_user}
+        end)
+
+      assert result.email == "[email protected]"
+      assert Repo.get!(User, user.id).email == "[email protected]"
+      refute Repo.get!(User, user.id).email == original_email
+    end
+
+    test "commits transaction when :ok is returned" do
+      user = insert(:user)
+      original_email = user.email
+
+      {:ok, result} =
+        Repo.transact(fn _repo ->
+          {:ok, _updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          :ok
+        end)
+
+      assert result == nil
+      assert Repo.get!(User, user.id).email == "[email protected]"
+      refute Repo.get!(User, user.id).email == original_email
+    end
+
+    test "rolls back transaction when anything else is returned" do
+      user = insert(:user)
+      original_email = user.email
+
+      # Test plain error atom
+      {:error, result} =
+        Repo.transact(fn _repo ->
+          {:ok, _updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          :error
+        end)
+
+      assert result == :error
+      assert Repo.get!(User, user.id).email == original_email
+
+      # Test error tuple
+      {:error, result} =
+        Repo.transact(fn _repo ->
+          {:ok, _updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          {:error, "reason"}
+        end)
+
+      assert result == "reason"
+      assert Repo.get!(User, user.id).email == original_email
+
+      # Test unexpected return value
+      {:error, result} =
+        Repo.transact(fn _repo ->
+          {:ok, _updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          "unexpected"
+        end)
+
+      assert result == "unexpected"
+      assert Repo.get!(User, user.id).email == original_email
+    end
+
+    test "rolls back transaction when an error is raised" do
+      user = insert(:user)
+      original_email = user.email
+
+      assert_raise RuntimeError, "boom", fn ->
+        Repo.transact(fn _repo ->
+          {:ok, _updated_user} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+          raise "boom"
+        end)
+      end
+
+      assert Repo.get!(User, user.id).email == original_email
+    end
+
+    test "commits nested transactions when all succeed" do
+      user = insert(:user)
+      original_email = user.email
+
+      {:ok, result} =
+        Repo.transact(fn _repo ->
+          {:ok, user1} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+
+          {:ok, user2} =
+            Repo.transact(fn _repo ->
+              user1 |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+            end)
+
+          {:ok, user2}
+        end)
+
+      assert result.email == "[email protected]"
+      assert Repo.get!(User, user.id).email == "[email protected]"
+      refute Repo.get!(User, user.id).email == original_email
+    end
+
+    test "rolls back nested transactions when inner transaction fails" do
+      user = insert(:user)
+      original_email = user.email
+
+      {:error, result} =
+        Repo.transact(fn _repo ->
+          {:ok, user1} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+
+          Repo.transact(fn _repo ->
+            {:ok, _user2} = user1 |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+            {:error, :inner_failed}
+          end)
+
+          {:ok, user1}
+        end)
+
+      assert result == :rollback
+      assert Repo.get!(User, user.id).email == original_email
+    end
+
+    test "rolls back nested transactions when outer transaction fails" do
+      user = insert(:user)
+      original_email = user.email
+
+      {:error, result} =
+        Repo.transact(fn _repo ->
+          {:ok, user1} = user |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+
+          {:ok, _user2} =
+            Repo.transact(fn _repo ->
+              user1 |> Ecto.Changeset.change(%{email: "[email protected]"}) |> Repo.update()
+            end)
+
+          {:error, :outer_failed}
+        end)
+
+      assert result == :outer_failed
+      assert Repo.get!(User, user.id).email == original_email
+    end
+  end
+end