update examples and readme and doc

README.md

@@ -95,15 +95,7 @@ To start a postgres container when running tests, that also enables testing of a
   @impl true
   def start(_type, _args) do
     if Mix.env() == :test do
-      {:ok, _container} =
-        Testcontainers.Ecto.postgres_container(
-          app: :my_app,
-          user: "postgres",
-          password: "postgres",
-          # to avoid port collision set the same port in config/test.exs
-          # or comment this out
-          port: 5433 
-        )
+      {:ok, _container} = Testcontainers.Ecto.postgres_container(app: :my_app)
     end
 
     # .. other setup code
@@ -112,6 +104,8 @@ To start a postgres container when running tests, that also enables testing of a
 
 This will start a postgres container that will be terminated when the test process ends.
 
+The database config in config/test.exs will be temporaly updated in-memory with the random host port on the container, and other properties like username, password and database. In most cases these will default to "test" unless overridden.
+
 See documentation on [Testcontainers.Ecto](https://hexdocs.pm/testcontainers/Testcontainers.Ecto.html) for more information about the options it can take.
 
 There is an example repo here with a bare bones phoenix application, where the only changes are the use of the ecto function and removing the test alias that interferes with it:

examples/phoenix_project/lib/hello/application.ex

@@ -8,13 +8,7 @@ defmodule Hello.Application do
   @impl true
   def start(_type, _args) do
     if Mix.env() == :test do
-      {:ok, _container} =
-        Testcontainers.Ecto.postgres_container(
-          app: :hello,
-          user: "postgres",
-          password: "postgres",
-          database: "hello_test#{System.get_env("MIX_TEST_PARTITION")}"
-        )
+      {:ok, _container} = Testcontainers.Ecto.postgres_container(app: :hello)
     end
 
     # to use mysql, change

lib/ecto.ex

@@ -18,7 +18,6 @@ defmodule Testcontainers.Ecto do
     - `:app` - The current application's atom, necessary for building paths and other application-specific logic. This is a required parameter.
     - `:repo` (optional) - The Ecto repository module for database interaction. If not provided, it is inferred from the `:app` option using the default naming convention (e.g., `MyApp.Repo`).
     - `:image` (optional) - Specifies the Docker image for the Postgres container. This must be a legitimate Postgres image, with the image name beginning with "postgres". If omitted, the default is "postgres:15".
-    - `:port` (optional) - Specifies the exposed port for the Postgres container (defaults to 5432). Does not translate to host port, which is dynamically assigned.
     - `:user` (optional) - Sets the username for the Postgres instance (defaults to "postgres").
     - `:password` (optional) - Determines the password for the Postgres user (defaults to "postgres").
     - `:database` (optional) - Specifies the name of the database to be created within the Postgres instance. If not provided, the default behavior is to create a database with the name derived from the application's atom, appended with "_test".
@@ -114,7 +113,6 @@ defmodule Testcontainers.Ecto do
     - `:app` - The current application's atom, necessary for building paths and other application-specific logic. This is a required parameter.
     - `:repo` (optional) - The Ecto repository module for database interaction. If not provided, it is inferred from the `:app` option using the default naming convention (e.g., `MyApp.Repo`).
     - `:image` (optional) - Specifies the Docker image for the Mysql container. This must be a legitimate Mysql image, with the image name beginning with "mysql". If omitted, the default is "mysql:8".
-    - `:port` (optional) - Specifies the exposed port for the Mysql container (defaults to 3306). Does not translate to host port, which is dynamically assigned.
     - `:user` (optional) - Sets the username for the Mysql instance (defaults to "test").
     - `:password` (optional) - Determines the password for the Mysql user (defaults to "test").
     - `:database` (optional) - Specifies the name of the database to be created within the Mysql instance. If not provided, the default behavior is to create a database with the name derived from the application's atom, appended with "_test".
@@ -231,10 +229,6 @@ defmodule Testcontainers.Ecto do
           repo
       end
 
-    if not :erlang.function_exported(repo, :__info__, 1) do
-      raise ArgumentError, "Repo is invalid: repo=#{inspect(repo)}"
-    end
-
     user = Keyword.get(options, :user, "test")
     password = Keyword.get(options, :password, "test")
     database = Keyword.get(options, :database, "#{Atom.to_string(app)}_test")
@@ -247,12 +241,11 @@ defmodule Testcontainers.Ecto do
       end
 
     image = Keyword.get(options, :image, container_module.default_image_with_tag())
-    container_port = Keyword.get(options, :port, container_module.default_port())
 
     config =
       container_module.new()
       |> container_module.with_image(image)
-      |> container_module.with_port(container_port)
+      |> container_module.with_port(container_module.default_port())
       |> container_module.with_user(user)
       |> container_module.with_database(database)
       |> container_module.with_password(password)

test/ecto_errors_test.exs

@@ -1,10 +1,10 @@
-defmodule Testcontainers.EctoMysqlTest do
+defmodule Testcontainers.EctoErrorsTest do
   use ExUnit.Case, async: true
 
   import Testcontainers.Ecto
 
   test "repo cannot be nil" do
-    assert_raise ArgumentError, "Repo is invalid: repo=Testcontainers.Repo", fn ->
+    assert_raise FunctionClauseError, "no function clause matching in Keyword.merge/2", fn ->
       mysql_container(
         app: :testcontainers,
         repo: nil

test/ecto_mysql_test.exs

@@ -5,6 +5,8 @@ defmodule Testcontainers.EctoMysqlTest do
 
   @moduletag timeout: 300_000
 
+  require Testcontainers.MysqlRepo
+
   test "can use ecto function" do
     {:ok, container} =
       mysql_container(

test/ecto_postgres_test.exs

@@ -5,6 +5,8 @@ defmodule Testcontainers.EctoPostgresTest do
 
   @moduletag timeout: 300_000
 
+  require Testcontainers.PostgresRepo
+
   test "can use ecto function" do
     {:ok, container} =
       postgres_container(