Refactor OpenApiTypesense.Connection.new/1

Adding missing validation and tests when making a new connection.

Author: kianmeng

lib/open_api_typesense/connection.ex

@@ -20,33 +20,52 @@ defmodule OpenApiTypesense.Connection do
   Setting new connection or using the default config.
 
   > #### On using this function {: .info}
-  > Functions e.g. `OpenApiTypesense.Health.health` don't need to explicitly pass this
+  > Functions e.g. `OpenApiTypesense.Health.health/0` don't need to explicitly pass this
   > unless you want to use another connection. Also, `api_key` is hidden when invoking
   > this function.
 
   ## Examples
+
       iex> alias OpenApiTypesense.Connection
-      
+
       iex> conn = Connection.new()
       %OpenApiTypesense.Connection{
         host: "localhost",
         port: 8108,
         scheme: "http",
         ...
       }
+
+      iex> Connection.new(%{})
+      ** (ArgumentError) Missing required fields: [:port, :scheme, :host, :api_key]
+          (open_api_typesense 0.2.0) lib/open_api_typesense/connection.ex:56: OpenApiTypesense.Connection.new/1
+      iex:2: (file)
+
   """
   @doc since: "0.2.0"
   @spec new(connection :: t() | map()) :: %__MODULE__{}
-  def new(connection \\ defaults()) when is_map(connection) do
-    %__MODULE__{
-      host: Map.get(connection, :host),
-      api_key: Map.get(connection, :api_key),
-      port: Map.get(connection, :port),
-      scheme: Map.get(connection, :scheme)
-    }
+
+  def new(connection \\ defaults())
+
+  def new(connection) when is_map(connection) do
+    missing_fields = required_fields() -- Map.keys(connection)
+
+    if missing_fields == [] do
+      struct(__MODULE__, connection)
+    else
+      raise ArgumentError, "Missing required fields: #{inspect(missing_fields)}"
+    end
+  end
+
+  def new(_) do
+    raise ArgumentError, "Expected a map for connection options"
+  end
+
+  @spec required_fields :: map()
+  defp required_fields do
+    struct(__MODULE__, %{}) |> Map.drop([:__struct__]) |> Map.keys()
   end
 
-  @doc since: "0.2.0"
   @spec defaults :: map()
   defp defaults do
     %{

test/open_api_typesense_connection_test.exs

@@ -0,0 +1,42 @@
+defmodule OpenApiTypesense.ConnectionTest do
+  use ExUnit.Case, async: true
+
+  alias OpenApiTypesense.Connection
+
+  test "new/0 using the default config to creates a connection struct" do
+    conn = Connection.new()
+
+    assert conn == %Connection{
+             api_key: "xyz",
+             host: "localhost",
+             port: 8108,
+             scheme: "http"
+           }
+  end
+
+  test "new/1 with custom fields creates a connection struct" do
+    conn =
+      Connection.new(%{
+        host: "otherhost",
+        port: 9200,
+        scheme: "https",
+        api_key: "myapikey"
+      })
+
+    assert conn == %Connection{
+             api_key: "myapikey",
+             host: "otherhost",
+             port: 9200,
+             scheme: "https"
+           }
+  end
+
+  test "new/1 with empty map raises ArgumentError" do
+    msg = "Missing required fields: [:port, :scheme, :host, :api_key]"
+    assert_raise ArgumentError, msg, fn -> Connection.new(%{}) end
+  end
+
+  test "new/1 with invalid data type raises ArgumentError" do
+    assert_raise ArgumentError, fn -> Connection.new("invalid") end
+  end
+end