add bridge context

14 files changed, 510 insertions, 2 deletions

diff --git a/config/config.exs b/config/config.exs
index 8d782dc..692048a 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -7,6 +7,9 @@
 # General application configuration
 use Mix.Config
 
+config :matrix_app_service,
+  ecto_repos: [MatrixAppService.Repo]
+
 # Configures the endpoint
 config :matrix_app_service, MatrixAppServiceWeb.Endpoint,
   url: [host: "localhost"],
diff --git a/config/test.exs b/config/test.exs
index ed14857..1402cf0 100644
--- a/config/test.exs
+++ b/config/test.exs
@@ -1,5 +1,17 @@
 use Mix.Config
 
+# Configure your database
+#
+# The MIX_TEST_PARTITION environment variable can be used
+# to provide built-in test partitioning in CI environment.
+# Run `mix help test` for more information.
+config :matrix_app_service, MatrixAppService.Repo,
+  username: "postgres",
+  password: "postgres",
+  database: "matrix_app_service_test#{System.get_env("MIX_TEST_PARTITION")}",
+  hostname: "localhost",
+  pool: Ecto.Adapters.SQL.Sandbox
+
 # We don't run a server during test. If one is required,
 # you can enable the server option below.
 config :matrix_app_service, MatrixAppServiceWeb.Endpoint,
diff --git a/lib/matrix_app_service/application.ex b/lib/matrix_app_service/application.ex
index 383c0f9..ae935eb 100644
--- a/lib/matrix_app_service/application.ex
+++ b/lib/matrix_app_service/application.ex
@@ -21,7 +21,8 @@ defmodule MatrixAppService.Application do
       if start_endpoint?() do
         [
           # MatrixAppServiceWeb.Endpoint
-          {MatrixAppServiceWeb.Endpoint, endpoint_config()}
+          {MatrixAppServiceWeb.Endpoint, endpoint_config()},
+          MatrixAppService.Repo
           | children
         ]
       else
diff --git a/lib/matrix_app_service/bridge.ex b/lib/matrix_app_service/bridge.ex
new file mode 100644
index 0000000..e0e0fee
--- /dev/null
+++ b/lib/matrix_app_service/bridge.ex
@@ -0,0 +1,3 @@
+defmodule MatrixAppService.Bridge do
+  use MatrixAppService.BridgeConfig, repo: MatrixAppService.Repo
+end
diff --git a/lib/matrix_app_service/bridge/room.ex b/lib/matrix_app_service/bridge/room.ex
new file mode 100644
index 0000000..c40e0ed
--- /dev/null
+++ b/lib/matrix_app_service/bridge/room.ex
@@ -0,0 +1,21 @@
+defmodule MatrixAppService.Bridge.Room do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "rooms" do
+    field :data, :map
+    field :local_id, :string
+    field :remote_id, :string
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(room, attrs) do
+    room
+    |> cast(attrs, [:local_id, :remote_id, :data])
+    # |> validate_required([:local_id, :remote_id, :data])
+    |> unique_constraint(:local_id)
+    |> unique_constraint(:remote_id)
+  end
+end
diff --git a/lib/matrix_app_service/bridge/user.ex b/lib/matrix_app_service/bridge/user.ex
new file mode 100644
index 0000000..aaa3c46
--- /dev/null
+++ b/lib/matrix_app_service/bridge/user.ex
@@ -0,0 +1,21 @@
+defmodule MatrixAppService.Bridge.User do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "users" do
+    field :data, :map
+    field :local_id, :string
+    field :remote_id, :string
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(user, attrs) do
+    user
+    |> cast(attrs, [:local_id, :remote_id, :data])
+    # |> validate_required([:local_id, :remote_id, :data])
+    |> unique_constraint(:local_id)
+    |> unique_constraint(:remote_id)
+  end
+end
diff --git a/lib/matrix_app_service/bridge_config.ex b/lib/matrix_app_service/bridge_config.ex
new file mode 100644
index 0000000..5356caf
--- /dev/null
+++ b/lib/matrix_app_service/bridge_config.ex
@@ -0,0 +1,221 @@
+defmodule MatrixAppService.BridgeConfig do
+  @moduledoc """
+  The Bridge config.
+  """
+
+  defmacro __using__([repo: repo]) do
+    quote bind_quoted: [repo: repo] do
+      @repo repo
+
+      import Ecto.Query, warn: false
+      # alias MatrixAppService.Repo
+
+      alias MatrixAppService.Bridge.User
+
+      @doc """
+      Returns the list of users.
+
+      ## Examples
+
+          iex> list_users()
+          [%User{}, ...]
+
+      """
+      def list_users do
+        @repo.all(User)
+      end
+
+      @doc """
+      Gets a single user.
+
+      Raises `Ecto.NoResultsError` if the User does not exist.
+
+      ## Examples
+
+          iex> get_user!(123)
+          %User{}
+
+          iex> get_user!(456)
+          ** (Ecto.NoResultsError)
+
+      """
+      def get_user!(id), do: @repo.get!(User, id)
+
+      def get_user_by_local_id(local_id), do: @repo.get_by(User, local_id: local_id) || %User{local_id: local_id}
+      def get_user_by_remote_id(remote_id), do: @repo.get_by(User, remote_id: remote_id) || %User{remote_id: remote_id}
+
+      @doc """
+      Creates a user.
+
+      ## Examples
+
+          iex> create_user(%{field: value})
+          {:ok, %User{}}
+
+          iex> create_user(%{field: bad_value})
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def create_user(attrs \\ %{}) do
+        %User{}
+        |> User.changeset(attrs)
+        |> @repo.insert()
+      end
+
+      def upsert_user(attrs, selectors) do
+        with %User{} = user <- @repo.get_by(User, selectors) do
+          update_user(user, attrs)
+        else
+          _ ->
+            create_user(Enum.into(selectors, attrs, fn {k, v} -> {to_string(k), v} end))
+        end
+      end
+
+      @doc """
+      Updates a user.
+
+      ## Examples
+
+          iex> update_user(user, %{field: new_value})
+          {:ok, %User{}}
+
+          iex> update_user(user, %{field: bad_value})
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def update_user(%User{} = user, attrs) do
+        user
+        |> User.changeset(attrs)
+        |> @repo.update()
+      end
+
+      @doc """
+      Deletes a user.
+
+      ## Examples
+
+          iex> delete_user(user)
+          {:ok, %User{}}
+
+          iex> delete_user(user)
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def delete_user(%User{} = user) do
+        @repo.delete(user)
+      end
+
+      @doc """
+      Returns an `%Ecto.Changeset{}` for tracking user changes.
+
+      ## Examples
+
+          iex> change_user(user)
+          %Ecto.Changeset{data: %User{}}
+
+      """
+      def change_user(%User{} = user, attrs \\ %{}) do
+        User.changeset(user, attrs)
+      end
+
+      alias MatrixAppService.Bridge.Room
+
+      @doc """
+      Returns the list of rooms.
+
+      ## Examples
+
+          iex> list_rooms()
+          [%Room{}, ...]
+
+      """
+      def list_rooms do
+        @repo.all(Room)
+      end
+
+      @doc """
+      Gets a single room.
+
+      Raises `Ecto.NoResultsError` if the Room does not exist.
+
+      ## Examples
+
+          iex> get_room!(123)
+          %Room{}
+
+          iex> get_room!(456)
+          ** (Ecto.NoResultsError)
+
+      """
+      def get_room!(id), do: @repo.get!(Room, id)
+
+      def get_room_by_local_id(local_id), do: @repo.get_by(Room, local_id: local_id) || %Room{local_id: local_id}
+      def get_room_by_remote_id(remote_id), do: @repo.get_by(Room, remote_id: remote_id) || %Room{remote_id: remote_id}
+
+      @doc """
+      Creates a room.
+
+      ## Examples
+
+          iex> create_room(%{field: value})
+          {:ok, %Room{}}
+
+          iex> create_room(%{field: bad_value})
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def create_room(attrs \\ %{}) do
+        %Room{}
+        |> Room.changeset(attrs)
+        |> @repo.insert()
+      end
+
+      @doc """
+      Updates a room.
+
+      ## Examples
+
+          iex> update_room(room, %{field: new_value})
+          {:ok, %Room{}}
+
+          iex> update_room(room, %{field: bad_value})
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def update_room(%Room{} = room, attrs) do
+        room
+        |> Room.changeset(attrs)
+        |> @repo.update()
+      end
+
+      @doc """
+      Deletes a room.
+
+      ## Examples
+
+          iex> delete_room(room)
+          {:ok, %Room{}}
+
+          iex> delete_room(room)
+          {:error, %Ecto.Changeset{}}
+
+      """
+      def delete_room(%Room{} = room) do
+        @repo.delete(room)
+      end
+
+      @doc """
+      Returns an `%Ecto.Changeset{}` for tracking room changes.
+
+      ## Examples
+
+          iex> change_room(room)
+          %Ecto.Changeset{data: %Room{}}
+
+      """
+      def change_room(%Room{} = room, attrs \\ %{}) do
+        Room.changeset(room, attrs)
+      end
+    end
+  end
+end
diff --git a/lib/matrix_app_service/migrations.ex b/lib/matrix_app_service/migrations.ex
new file mode 100644
index 0000000..e6ce469
--- /dev/null
+++ b/lib/matrix_app_service/migrations.ex
@@ -0,0 +1,26 @@
+defmodule MatrixAppService.Migrations do
+  use Ecto.Migration
+
+  def change do
+    create table(:users) do
+      add :local_id, :string
+      add :remote_id, :string
+      add :data, :map
+
+      timestamps()
+    end
+    create unique_index(:users, [:local_id])
+    create unique_index(:users, [:remote_id])
+
+
+    create table(:rooms) do
+      add :local_id, :string
+      add :remote_id, :string
+      add :data, :map
+
+      timestamps()
+    end
+    create unique_index(:rooms, [:local_id])
+    create unique_index(:rooms, [:remote_id])
+  end
+end
diff --git a/lib/matrix_app_service/repo.ex b/lib/matrix_app_service/repo.ex
new file mode 100644
index 0000000..c52348a
--- /dev/null
+++ b/lib/matrix_app_service/repo.ex
@@ -0,0 +1,5 @@
+defmodule MatrixAppService.Repo do
+  use Ecto.Repo,
+    otp_app: :matrix_app_service,
+    adapter: Ecto.Adapters.Postgres
+end
diff --git a/mix.exs b/mix.exs
index bb0fe80..e0cffe4 100644
--- a/mix.exs
+++ b/mix.exs
@@ -59,11 +59,13 @@ defmodule MatrixAppService.MixProject do
       {:telemetry_poller, "~> 0.4"},
       {:jason, "~> 1.0"},
       {:plug_cowboy, "~> 2.0"},
+      {:phoenix_ecto, "~> 4.1"},
       {:ecto_sql, "~> 3.4"},
       {:polyjuice_client, "~> 0.3.1"},
       {:ex_doc, "~> 0.22", only: :dev, runtime: false},
       {:junit_formatter, "~> 3.1", only: :test},
-      {:cobertura_cover, "~> 0.9.0", only: :test}
+      {:cobertura_cover, "~> 0.9.0", only: :test},
+      {:postgrex, ">= 0.0.0", only: :test}
     ]
   end
 
diff --git a/mix.lock b/mix.lock
index 951e330..9782076 100644
--- a/mix.lock
+++ b/mix.lock
@@ -24,6 +24,7 @@
   "nimble_parsec": {:hex, :nimble_parsec, "1.1.0", "3a6fca1550363552e54c216debb6a9e95bd8d32348938e13de5eda962c0d7f89", [:mix], [], "hexpm", "08eb32d66b706e913ff748f11694b17981c0b04a33ef470e33e11b3d3ac8f54b"},
   "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm", "17ef63abde837ad30680ea7f857dd9e7ced9476cdd7b0394432af4bfc241b960"},
   "phoenix": {:hex, :phoenix, "1.5.7", "2923bb3af924f184459fe4fa4b100bd25fa6468e69b2803dfae82698269aa5e0", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_html, "~> 2.13", [hex: :phoenix_html, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.0", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:plug, "~> 1.10", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 1.0 or ~> 2.2", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.1.2 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "774cd64417c5a3788414fdbb2be2eb9bcd0c048d9e6ad11a0c1fd67b7c0d0978"},
+  "phoenix_ecto": {:hex, :phoenix_ecto, "4.2.1", "13f124cf0a3ce0f1948cf24654c7b9f2347169ff75c1123f44674afee6af3b03", [:mix], [{:ecto, "~> 3.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 2.14.2 or ~> 2.15", [hex: :phoenix_html, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "478a1bae899cac0a6e02be1deec7e2944b7754c04e7d4107fc5a517f877743c0"},
   "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.0.0", "a1ae76717bb168cdeb10ec9d92d1480fec99e3080f011402c0a2d68d47395ffb", [:mix], [], "hexpm", "c52d948c4f261577b9c6fa804be91884b381a7f8f18450c5045975435350f771"},
   "plug": {:hex, :plug, "1.11.0", "f17217525597628298998bc3baed9f8ea1fa3f1160aa9871aee6df47a6e4d38e", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2d9c633f0499f9dc5c2fd069161af4e2e7756890b81adcbb2ceaa074e8308876"},
   "plug_cowboy": {:hex, :plug_cowboy, "2.4.1", "779ba386c0915027f22e14a48919a9545714f849505fa15af2631a0d298abf0f", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:cowboy_telemetry, "~> 0.3", [hex: :cowboy_telemetry, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "d72113b6dff7b37a7d9b2a5b68892808e3a9a752f2bf7e503240945385b70507"},
@@ -32,6 +33,7 @@
   "polyjuice_client": {:hex, :polyjuice_client, "0.3.1", "cc312602a8da0d4d61b0a890bb72d9c6662f17cd0fc5782d8f7358274e3e6e4b", [:mix], [{:hackney, "~> 1.12", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.2", [hex: :jason, repo: "hexpm", optional: false]}, {:mutex, "~> 1.1.3", [hex: :mutex, repo: "hexpm", optional: false]}, {:polyjuice_util, "~> 0.1.0", [hex: :polyjuice_util, repo: "hexpm", optional: false]}], "hexpm", "e9585faab7562cac3e91a64d328905cefabc74219fafa9e77e09f4e5e4e82957"},
   "polyjuice_util": {:hex, :polyjuice_util, "0.1.0", "69901959c143245b47829c8302d0605dff6c0e1c3b116730c162982e0f512ee0", [:mix], [], "hexpm", "af5d1f614f52ce1da59a1f5a7c49249a2dbfda279d99d52d1b4e83e84c19a8d5"},
   "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm", "dad79704ce5440f3d5a3681c8590b9dc25d1a561e8f5a9c995281012860901e3"},
+  "postgrex": {:hex, :postgrex, "0.15.7", "724410acd48abac529d0faa6c2a379fb8ae2088e31247687b16cacc0e0883372", [:mix], [{:connection, "~> 1.0", [hex: :connection, repo: "hexpm", optional: false]}, {:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "88310c010ff047cecd73d5ceca1d99205e4b1ab1b9abfdab7e00f5c9d20ef8f9"},
   "ranch": {:hex, :ranch, "1.7.1", "6b1fab51b49196860b733a49c07604465a47bdb78aa10c1c16a3d199f7f8c881", [:rebar3], [], "hexpm", "451d8527787df716d99dc36162fca05934915db0b6141bbdac2ea8d3c7afc7d7"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
   "telemetry": {:hex, :telemetry, "0.4.2", "2808c992455e08d6177322f14d3bdb6b625fbcfd233a73505870d8738a2f4599", [:rebar3], [], "hexpm", "2d1419bd9dda6a206d7b5852179511722e2b18812310d304620c7bd92a13fcef"},
diff --git a/priv/repo/migrations/20201209095612_migrate_itself.exs b/priv/repo/migrations/20201209095612_migrate_itself.exs
new file mode 100644
index 0000000..04df688
--- /dev/null
+++ b/priv/repo/migrations/20201209095612_migrate_itself.exs
@@ -0,0 +1,7 @@
+defmodule MatrixAppService.Repo.Migrations.MigrateItself do
+  use Ecto.Migration
+
+  def change do
+    MatrixAppService.Migrations.change()
+  end
+end
diff --git a/test/matrix_app_service/bridge_test.exs b/test/matrix_app_service/bridge_test.exs
new file mode 100644
index 0000000..46acffb
--- /dev/null
+++ b/test/matrix_app_service/bridge_test.exs
@@ -0,0 +1,131 @@
+defmodule MatrixAppService.BridgeTest do
+  use MatrixAppService.DataCase
+
+  alias MatrixAppService.Bridge
+
+  describe "users" do
+    alias MatrixAppService.Bridge.User
+
+    @valid_attrs %{data: %{}, local_id: "some local_id", remote_id: "some remote_id"}
+    @update_attrs %{data: %{}, local_id: "some updated local_id", remote_id: "some updated remote_id"}
+    # @invalid_attrs %{data: nil, local_id: nil, remote_id: nil}
+
+    def user_fixture(attrs \\ %{}) do
+      {:ok, user} =
+        attrs
+        |> Enum.into(@valid_attrs)
+        |> Bridge.create_user()
+
+      user
+    end
+
+    test "list_users/0 returns all users" do
+      user = user_fixture()
+      assert Bridge.list_users() == [user]
+    end
+
+    test "get_user!/1 returns the user with given id" do
+      user = user_fixture()
+      assert Bridge.get_user!(user.id) == user
+    end
+
+    test "create_user/1 with valid data creates a user" do
+      assert {:ok, %User{} = user} = Bridge.create_user(@valid_attrs)
+      assert user.data == %{}
+      assert user.local_id == "some local_id"
+      assert user.remote_id == "some remote_id"
+    end
+
+#     test "create_user/1 with invalid data returns error changeset" do
+#       assert {:error, %Ecto.Changeset{}} = Bridge.create_user(@invalid_attrs)
+#     end
+
+    test "update_user/2 with valid data updates the user" do
+      user = user_fixture()
+      assert {:ok, %User{} = user} = Bridge.update_user(user, @update_attrs)
+      assert user.data == %{}
+      assert user.local_id == "some updated local_id"
+      assert user.remote_id == "some updated remote_id"
+    end
+
+#     test "update_user/2 with invalid data returns error changeset" do
+#       user = user_fixture()
+#       assert {:error, %Ecto.Changeset{}} = Bridge.update_user(user, @invalid_attrs)
+#       assert user == Bridge.get_user!(user.id)
+#     end
+
+    test "delete_user/1 deletes the user" do
+      user = user_fixture()
+      assert {:ok, %User{}} = Bridge.delete_user(user)
+      assert_raise Ecto.NoResultsError, fn -> Bridge.get_user!(user.id) end
+    end
+
+    test "change_user/1 returns a user changeset" do
+      user = user_fixture()
+      assert %Ecto.Changeset{} = Bridge.change_user(user)
+    end
+  end
+
+  describe "rooms" do
+    alias MatrixAppService.Bridge.Room
+
+    @valid_attrs %{data: %{}, local_id: "some local_id", remote_id: "some remote_id"}
+    @update_attrs %{data: %{}, local_id: "some updated local_id", remote_id: "some updated remote_id"}
+    # @invalid_attrs %{data: nil, local_id: nil, remote_id: nil}
+
+    def room_fixture(attrs \\ %{}) do
+      {:ok, room} =
+        attrs
+        |> Enum.into(@valid_attrs)
+        |> Bridge.create_room()
+
+      room
+    end
+
+    test "list_rooms/0 returns all rooms" do
+      room = room_fixture()
+      assert Bridge.list_rooms() == [room]
+    end
+
+    test "get_room!/1 returns the room with given id" do
+      room = room_fixture()
+      assert Bridge.get_room!(room.id) == room
+    end
+
+    test "create_room/1 with valid data creates a room" do
+      assert {:ok, %Room{} = room} = Bridge.create_room(@valid_attrs)
+      assert room.data == %{}
+      assert room.local_id == "some local_id"
+      assert room.remote_id == "some remote_id"
+    end
+
+#     test "create_room/1 with invalid data returns error changeset" do
+#       assert {:error, %Ecto.Changeset{}} = Bridge.create_room(@invalid_attrs)
+#     end
+
+    test "update_room/2 with valid data updates the room" do
+      room = room_fixture()
+      assert {:ok, %Room{} = room} = Bridge.update_room(room, @update_attrs)
+      assert room.data == %{}
+      assert room.local_id == "some updated local_id"
+      assert room.remote_id == "some updated remote_id"
+    end
+
+#     test "update_room/2 with invalid data returns error changeset" do
+#       room = room_fixture()
+#       assert {:error, %Ecto.Changeset{}} = Bridge.update_room(room, @invalid_attrs)
+#       assert room == Bridge.get_room!(room.id)
+#     end
+
+    test "delete_room/1 deletes the room" do
+      room = room_fixture()
+      assert {:ok, %Room{}} = Bridge.delete_room(room)
+      assert_raise Ecto.NoResultsError, fn -> Bridge.get_room!(room.id) end
+    end
+
+    test "change_room/1 returns a room changeset" do
+      room = room_fixture()
+      assert %Ecto.Changeset{} = Bridge.change_room(room)
+    end
+  end
+end
diff --git a/test/support/data_case.ex b/test/support/data_case.ex
new file mode 100644
index 0000000..475f748
--- /dev/null
+++ b/test/support/data_case.ex
@@ -0,0 +1,53 @@
+defmodule MatrixAppService.DataCase do
+  @moduledoc """
+  This module defines the setup for tests requiring
+  access to the application's data layer.
+  You may define functions here to be used as helpers in
+  your tests.
+  Finally, if the test case interacts with the database,
+  it cannot be async. For this reason, every test runs
+  inside a transaction which is reset at the beginning
+  of the test unless the test case is marked as async.
+  """
+
+  use ExUnit.CaseTemplate
+
+  alias Ecto.Adapters.SQL.Sandbox
+  alias Ecto.Changeset
+  alias MatrixAppService.Repo
+
+  using do
+    quote do
+      alias MatrixAppService.Repo
+
+      import Ecto
+      import Ecto.Changeset
+      import Ecto.Query
+      import MatrixAppService.DataCase
+    end
+  end
+
+  setup tags do
+    :ok = Sandbox.checkout(Repo)
+
+    unless tags[:async] do
+      Sandbox.mode(Repo, {:shared, self()})
+    end
+
+    :ok
+  end
+
+  @doc """
+  A helper that transform changeset errors to a map of messages.
+      assert {:error, changeset} = Accounts.create_user(%{password: "short"})
+      assert "password is too short" in errors_on(changeset).password
+      assert %{password: ["password is too short"]} = errors_on(changeset)
+  """
+  def errors_on(changeset) do
+    Changeset.traverse_errors(changeset, fn {message, opts} ->
+      Enum.reduce(opts, message, fn {key, value}, acc ->
+        String.replace(acc, "%{#{key}}", to_string(value))
+      end)
+    end)
+  end
+end