fix docs and add errors

Author: Steven Fuchs

guides/custom_fonts.md

@@ -64,16 +64,19 @@ In your scene, you need to make load both the `\*.metrics` file into the `Scenic
 
 
 ```elixir
-@font_folder :code.priv_dir(:my_app) |> Path.join("/static/fonts")
 @custom_font_hash "0IXAWqFTtjn6MKSgQOzxUgxNKGrmyhqz1e2d90PVHck"
 @custom_metrics_path :code.priv_dir(:scenic_example)
            |> Path.join("/static/fonts/Roboto_Slab/RobotoSlab-Regular.ttf.metrics")
 @custom_metrics_hash Scenic.Cache.Support.Hash.file!(@custom_metrics_path, :sha)
 
 def init(_, _opts) do
   # load the custom font
-  Cache.Static.Font.load(@font_folder, @custom_font_hash)
-  Cache.Static.FontMetrics.load(@custom_metrics_path, @custom_metrics_hash)
+  font_folder = :code.priv_dir(:my_app) |> Path.join("/static/fonts")
+  custom_metrics_path = :code.priv_dir(:scenic_example)
+           |> Path.join("/static/fonts/Roboto_Slab/RobotoSlab-Regular.ttf.metrics")
+  
+  Cache.Static.Font.load(font_folder, @custom_font_hash)
+  Cache.Static.FontMetrics.load(custom_metrics_path, @custom_metrics_hash)
 
   # no need to put the graph into state as we won't be using it again
   {:ok, nil, push: @graph}

lib/scenic/cache/static/font.ex

@@ -6,6 +6,7 @@
 defmodule Scenic.Cache.Static.Font do
   use Scenic.Cache.Base, name: "font", static: true
   alias Scenic.Cache.Support
+  require Logger
 
   # import IEx
 
@@ -176,6 +177,7 @@ defmodule Scenic.Cache.Static.Font do
           {:ok, hash}
         else
           err ->
+            Logger.error("Could not load font at #{font_folder}: #{inspect(err)}")
             err
         end
     end

lib/scenic/cache/static/font_metrics.ex

@@ -6,6 +6,7 @@
 defmodule Scenic.Cache.Static.FontMetrics do
   use Scenic.Cache.Base, name: "font_metrics", static: true
   alias Scenic.Cache.Support
+  require Logger
 
   @moduledoc """
   In memory cache for static font_metrics assets.
@@ -225,7 +226,9 @@ defmodule Scenic.Cache.Static.FontMetrics do
              {:ok, metrics} <- FontMetrics.from_binary(data) do
           put_new(hash, metrics, opts[:scope])
         else
-          err -> err
+          err ->
+            Logger.error("Could not load font metrics at #{path}: #{inspect(err)}")
+            err
         end
     end
   end

test/scenic/cache/static/font_metrics_test.exs

@@ -9,6 +9,7 @@ defmodule Scenic.Cache.Static.FontMetricsTest do
   alias Scenic.Cache.Base
   alias Scenic.Cache.Static
   alias Scenic.Cache.Support
+  import ExUnit.CaptureLog
 
   @base_path :code.priv_dir(:scenic)
              |> Path.join("static/font_metrics")
@@ -112,11 +113,15 @@ defmodule Scenic.Cache.Static.FontMetricsTest do
   end
 
   test "load passes through errors" do
-    assert Static.FontMetrics.load("wrong/path", @roboto_hash) ==
-             {:error, :enoent}
-
-    assert Static.FontMetrics.load(@roboto_path, "bad_hash") ==
-             {:error, :hash_failure}
+    assert capture_log(fn ->
+             assert Static.FontMetrics.load("wrong/path", @roboto_hash) ==
+                      {:error, :enoent}
+           end) =~ "Could not load font metrics at"
+
+    assert capture_log(fn ->
+             assert Static.FontMetrics.load(@roboto_path, "bad_hash") ==
+                      {:error, :hash_failure}
+           end) =~ "Could not load font metrics at"
   end
 
   # ============================================================================

test/scenic/cache/static/font_test.exs

@@ -9,6 +9,7 @@ defmodule Scenic.Cache.Static.FontTest do
   alias Scenic.Cache.Base
   alias Scenic.Cache.Static.Font
   alias Scenic.Cache.Support
+  import ExUnit.CaptureLog
 
   @folder File.cwd!()
           |> Path.join("test/artifacts")
@@ -115,11 +116,15 @@ defmodule Scenic.Cache.Static.FontTest do
   end
 
   test "load passes through errors" do
-    assert Font.load("wrong/path", @hash) ==
-             {:error, :not_found}
-
-    assert Font.load(@folder, "bad_hash") ==
-             {:error, :hash_failure}
+    assert capture_log(fn ->
+             assert Font.load("wrong/path", @hash) ==
+                      {:error, :not_found}
+           end) =~ "Could not load font at"
+
+    assert capture_log(fn ->
+             assert Font.load(@folder, "bad_hash") ==
+                      {:error, :hash_failure}
+           end) =~ "Could not load font at"
   end
 
   # ============================================================================