Fix compilation in project lacking Finch

Closes #204

lib/exvcr/adapter/finch/converter.ex

@@ -1,86 +1,91 @@
-defmodule ExVCR.Adapter.Finch.Converter do
-  @moduledoc """
-  Provides helpers to mock Finch methods.
-  """
-
-  use ExVCR.Converter
-
-  alias ExVCR.Util
-
-  defp string_to_response(string) do
-    response = Enum.map(string, fn({x, y}) -> {String.to_atom(x), y} end)
-    response = struct(ExVCR.Response, response)
-
-    response =
-      if response.type == "error" do
-        body = string_to_error_reason(response.body)
-        %{response | body: body}
-      else
-        response
-      end
-
-    response =
-      if is_map(response.headers) do
-        headers = response.headers
-                  |> Map.to_list
-                  |> Enum.map(fn({k,v}) -> {k, v} end)
-        %{response | headers: headers}
-      else
-        response
-      end
-
-    response
-  end
+if Code.ensure_loaded?(Finch) do
+  defmodule ExVCR.Adapter.Finch.Converter do
+    @moduledoc """
+    Provides helpers to mock Finch methods.
+    """
 
-  defp string_to_error_reason(reason) do
-    {reason_struct, _} = Code.eval_string(reason)
-    reason_struct
-  end
+    use ExVCR.Converter
 
-  defp request_to_string([request, finch_module]) do
-    request_to_string([request, finch_module, []])
-  end
+    alias ExVCR.Util
 
-  defp request_to_string([request, _finch_module, opts]) do
-    url = Util.build_url(request.scheme, request.host, request.path, request.port, request.query)
+    defp string_to_response(string) do
+      response = Enum.map(string, fn {x, y} -> {String.to_atom(x), y} end)
+      response = struct(ExVCR.Response, response)
 
-    %ExVCR.Request{
-      url: parse_url(url),
-      headers: parse_headers(request.headers),
-      method: String.downcase(request.method),
-      body: parse_request_body(request.body),
-      options: parse_options(sanitize_options(opts))
-    }
-  end
+      response =
+        if response.type == "error" do
+          body = string_to_error_reason(response.body)
+          %{response | body: body}
+        else
+          response
+        end
 
-  # If option value is tuple, make it as list, for encoding as json.
-  defp sanitize_options(options) do
-    Enum.map(options, fn({key, value}) ->
-      if is_tuple(value) do
-        {key, Tuple.to_list(value)}
-      else
-        {key, value}
-      end
-    end)
-  end
+      response =
+        if is_map(response.headers) do
+          headers =
+            response.headers
+            |> Map.to_list()
+            |> Enum.map(fn {k, v} -> {k, v} end)
 
-  defp response_to_string({:ok, %Finch.Response{} = response}), do: response_to_string(response)
+          %{response | headers: headers}
+        else
+          response
+        end
 
-  defp response_to_string(%Finch.Response{} = response) do
-    %ExVCR.Response{
-      type: "ok",
-      status_code: response.status,
-      headers: parse_headers(response.headers),
-      body: to_string(response.body)
-    }
-  end
+      response
+    end
 
-  defp response_to_string({:error, reason}) do
-    %ExVCR.Response{
-      type: "error",
-      body: error_reason_to_string(reason)
-    }
-  end
+    defp string_to_error_reason(reason) do
+      {reason_struct, _} = Code.eval_string(reason)
+      reason_struct
+    end
+
+    defp request_to_string([request, finch_module]) do
+      request_to_string([request, finch_module, []])
+    end
 
-  defp error_reason_to_string(reason), do: Macro.to_string(reason)
+    defp request_to_string([request, _finch_module, opts]) do
+      url =
+        Util.build_url(request.scheme, request.host, request.path, request.port, request.query)
+
+      %ExVCR.Request{
+        url: parse_url(url),
+        headers: parse_headers(request.headers),
+        method: String.downcase(request.method),
+        body: parse_request_body(request.body),
+        options: parse_options(sanitize_options(opts))
+      }
+    end
+
+    # If option value is tuple, make it as list, for encoding as json.
+    defp sanitize_options(options) do
+      Enum.map(options, fn {key, value} ->
+        if is_tuple(value) do
+          {key, Tuple.to_list(value)}
+        else
+          {key, value}
+        end
+      end)
+    end
+
+    defp response_to_string({:ok, %Finch.Response{} = response}), do: response_to_string(response)
+
+    defp response_to_string(%Finch.Response{} = response) do
+      %ExVCR.Response{
+        type: "ok",
+        status_code: response.status,
+        headers: parse_headers(response.headers),
+        body: to_string(response.body)
+      }
+    end
+
+    defp response_to_string({:error, reason}) do
+      %ExVCR.Response{
+        type: "error",
+        body: error_reason_to_string(reason)
+      }
+    end
+
+    defp error_reason_to_string(reason), do: Macro.to_string(reason)
+  end
 end