Add tests

Author: kipcole9

lib/image_lens_correction.ex

@@ -1,4 +1,4 @@
-defmodule ImageLensCorrection do
+defmodule Image.LensCorrection do
   @moduledoc """
 
 

mix.exs

@@ -7,6 +7,7 @@ defmodule ImageLensCorrection.MixProject do
       version: "0.1.0",
       elixir: "~> 1.14",
       start_permanent: Mix.env() == :prod,
+      elixirc_paths: elixirc_paths(Mix.env()),
       deps: deps()
     ]
   end
@@ -23,4 +24,17 @@ defmodule ImageLensCorrection.MixProject do
       {:image, path: "../image"}
     ]
   end
+
+  defp preferred_cli_env() do
+    []
+  end
+
+  def aliases do
+    []
+  end
+
+  defp elixirc_paths(:test), do: ["lib", "mix", "test"]
+  defp elixirc_paths(:dev), do: ["lib", "mix", "bench"]
+  defp elixirc_paths(:release), do: ["lib"]
+  defp elixirc_paths(_), do: ["lib"]
 end

test/distortion_correction_test.exs

@@ -0,0 +1,18 @@
+defmodule Image.DistortionCorrection.Test do
+  use ExUnit.Case, async: true
+  import Image.TestSupport
+
+  test "Image.distortion_correction/5" do
+    image_file = "gridlines_barrel.png"
+    validate_file = "gridlines_barrel_corrected.png"
+
+    image_path = image_path(image_file)
+    validate_path = validate_path(validate_file)
+
+    image = Image.open!(image_path)
+    {:ok, corrected} = Image.LensCorrection.radial_distortion_correction(image, -0.007715, 0.086731, 0.0)
+
+    # {:ok, _image} = Image.write(corrected, validate_path)
+    assert_images_equal(corrected, validate_path)
+  end
+end

test/image_lens_correction_test.exs

@@ -0,0 +1,90 @@
+defmodule Image.TestSupport do
+  import ExUnit.Assertions
+  alias Vix.Vips.Image, as: Vimage
+
+  @images_path Path.join(__DIR__, "images")
+  @validate_path Path.join(__DIR__, "validate")
+  @acceptable_similarity 1.1
+
+  @dialyzer {:nowarn_function, {:assert_files_equal, 2}}
+  def assert_files_equal(expected, result) do
+    assert File.read!(expected) == File.read!(result)
+  end
+
+  @dialyzer {:nowarn_function, {:assert_images_equal, 2}}
+  @dialyzer {:nowarn_function, {:assert_images_equal, 3}}
+
+  def assert_images_equal(calculated_image, validate, similarity \\ @acceptable_similarity)
+
+  def assert_images_equal(%Vimage{} = calculated_image, validate, similarity)
+      when is_binary(validate) do
+    validate_image = Image.open!(validate, access: :random)
+    compare_images(calculated_image, validate_image, similarity)
+  end
+
+  def assert_images_equal(calculated, validate, similarity)
+      when is_binary(calculated) and is_binary(validate) do
+    validate_image = Image.open!(validate, access: :random)
+    calculated_image = Image.open!(calculated, access: :random)
+
+    compare_images(calculated_image, validate_image, similarity)
+  end
+
+  def assert_images_equal(%Vimage{} = calculated, %Vimage{} = validate, similarity) do
+    compare_images(calculated, validate, similarity)
+  end
+
+  def image_path(name) do
+    Path.join(@images_path, name)
+  end
+
+  def validate_path(name) do
+    Path.join(@validate_path, name)
+  end
+
+  # From: https://github.com/libvips/libvips/discussions/2232
+  # Calculate a single number for the match between two images, calculate the sum
+  # of squares of differences,
+  @dialyzer {:nowarn_function, {:compare_images, 3}}
+  def compare_images(calculated_image, validate_image, acceptable_similarity) do
+    alias Image.Math
+    validate_path = Image.filename(validate_image)
+
+    {calculated_image, validate_image} =
+      if Vimage.format(calculated_image) == Vimage.format(validate_image) do
+        {calculated_image, validate_image}
+      else
+        {
+          Vix.Vips.Operation.cast!(calculated_image, :VIPS_FORMAT_UCHAR),
+          Vix.Vips.Operation.cast!(validate_image, :VIPS_FORMAT_UCHAR)
+        }
+      end
+
+    similarity =
+      calculated_image
+      |> Math.subtract!(validate_image)
+      |> Math.pow!(2)
+      |> Vix.Vips.Operation.avg!()
+
+    if similarity < acceptable_similarity do
+      assert true
+    else
+      path = String.replace(validate_path, "validate", "did_not_match")
+
+      comparison_image =
+        Vix.Vips.Operation.relational!(
+          calculated_image,
+          validate_image,
+          :VIPS_OPERATION_RELATIONAL_EQUAL
+        )
+
+      Image.write!(comparison_image, path)
+
+      flunk(
+        "Calculated image did not match pre-existing validation image. " <>
+          "Similarity score was #{inspect(similarity)}. " <>
+          "See the image at #{path} for the image diff."
+      )
+    end
+  end
+end

test/support/image_test_helpers.ex

@@ -1 +1,8 @@
+paths = Path.wildcard("test/support/did_not_match/**/*.{png,tif,jpg,webp,gif}")
+Enum.each(paths, &File.rm/1)
+
+Application.ensure_all_started(:telemetry)
+Application.ensure_all_started(:hackney)
+
+ExUnit.configure(exclude: [full: true], timeout: 120_000)
 ExUnit.start()