Add helpers for transition tests

test/remote/helpers/transition_helpers.rb

@@ -0,0 +1,128 @@
+require 'chroma'
+
+module TransitionHelpers
+  module Defaults
+    DURATION = 4500
+    PERIOD = 450
+    NUM_PERIODS = 10
+  end
+
+  def highlight_value(a, highlight_ix)
+    str = a
+      .each_with_index
+      .map do |x, i|
+        i == highlight_ix ? ">>#{x}<<" : x
+      end
+      .join(', ')
+    "[#{str}]"
+  end
+
+  def color_transitions_are_equal(expected:, seen:)
+    %i(hue saturation).each do |label|
+      e = expected.map { |x| x[label] }
+      s = seen.map { |x| x[label] }
+
+      transitions_are_equal(expected: e, seen: s, label: label, allowed_variation: label == :saturation ? 5 : 20)
+    end
+  end
+
+  def transitions_are_equal(expected:, seen:, allowed_variation: 0, label: nil)
+    generate_msg = ->(a, b, i) do
+      s = "Transition step value"
+
+      if !label.nil?
+        s << " for #{label} "
+      end
+
+      s << "at index #{i} "
+
+      s << if allowed_variation == 0
+        "should be equal to expected value.  Expected: #{a}, saw: #{b}."
+      else
+        "should be within #{allowed_variation} of expected value.  Expected: #{a}, saw: #{b}."
+      end
+
+      s << "  Steps:\n"
+      s << "  Expected : #{highlight_value(expected, i)},\n"
+      s << "  Seen     : #{highlight_value(seen, i)}"
+    end
+
+    expect(expected.length).to eq(seen.length)
+
+    expected.zip(seen).each_with_index do |x, i|
+      a, b = x
+      diff = (a - b).abs
+      expect(diff).to be <= allowed_variation, generate_msg.call(a, b, i)
+    end
+  end
+
+  def rgb_to_hs(*color)
+    if color.length > 1
+      r, g, b = color
+    else
+      r, g, b = coerce_color(color.first)
+    end
+
+    hsv = Chroma::Converters::HsvConverter.convert_rgb(Chroma::ColorModes::Rgb.new(r, g, b))
+    { hue: hsv.h.round, saturation: (100*hsv.s).round }
+  end
+
+  def coerce_color(c)
+    c.split(',').map(&:to_i) unless c.is_a?(Array)
+  end
+
+  def calculate_color_transition_steps(start_color:, end_color:, duration: nil, period: nil, num_periods: Defaults::NUM_PERIODS)
+    start_color = coerce_color(start_color)
+    end_color = coerce_color(end_color)
+
+    part_transitions = start_color.zip(end_color).map do |c|
+      s, e = c
+      calculate_transition_steps(start_value: s, end_value: e, duration: duration, period: period, num_periods: num_periods)
+    end
+
+    # If some colors don't transition, they'll stay at the same value while others move.
+    # Turn this: [[1,2,3], [0], [4,5,6]]
+    # Into this: [[1,2,3], [0,0,0], [4,5,6]]
+    longest = part_transitions.max_by { |x| x.length }.length
+    part_transitions.map! { |x| x + [x.last]*(longest-x.length) }
+
+    # Zip individual parts into 3-tuples
+    # Turn this: [[1,2,3], [0,0,0], [4,5,6]]
+    # Into this: [[1,0,4], [2,0,5], [3,0,6]]
+    transition_colors = part_transitions.first.zip(*part_transitions[1..part_transitions.length])
+
+    # Undergo the RGB -> HSV w/ value = 100
+    transition_colors.map do |x|
+      r, g, b = x
+      rgb_to_hs(r, g, b)
+    end
+  end
+
+  def calculate_transition_steps(start_value:, end_value:, duration: nil, period: nil, num_periods: Defaults::NUM_PERIODS)
+    if !duration.nil? || !period.nil?
+      period ||= Defaults::PERIOD
+      duration ||= Defaults::DURATION
+      num_periods = [1, (duration / period.to_f).ceil].max
+    end
+
+    diff = end_value - start_value
+    step_size = [1, (diff.abs / num_periods.to_f).ceil].max
+    step_size = -step_size if end_value < start_value
+
+    steps = []
+    val = start_value
+
+    while val != end_value
+      steps << val
+
+      if (end_value - val).abs < step_size.abs
+        val += (end_value - val)
+      else
+        val += step_size
+      end
+    end
+
+    steps << end_value
+    steps
+  end
+end

test/remote/spec/spec_helper.rb

@@ -1,6 +1,7 @@
 require 'dotenv'
 require './helpers/state_helpers'
 require './helpers/mqtt_helpers'
+require './helpers/transition_helpers'
 
 Dotenv.load('espmh.env')
 
@@ -22,6 +23,7 @@ Dotenv.load('espmh.env')
 RSpec.configure do |config|
   config.include StateHelpers
   config.include MqttHelpers
+  config.include TransitionHelpers
 
   # rspec-expectations config goes here. You can use an alternate
   # assertion/expectation library such as wrong or the stdlib/minitest