Merge branch 'feature-paginated' of cli/Chronobriq-API into master

app/models/paginated.rb

+module Paginated
+  DEFAULT_COUNT_BY_PAGE = 10
+  # can be overwritten
+  def count_by_page
+    DEFAULT_COUNT_BY_PAGE
+  end
+
+  def paginate(params)
+    page = (params.fetch :page, 0).to_i
+    start = page * count_by_page
+    offset(start).limit(count_by_page)
+  end
+end

test/models/paginated_test.rb

+require "test_helper"
+require_relative "../../app/models/paginated"
+
+class FakePaginated
+  include Paginated
+  DATA = ("a".."z").to_a
+
+  # fake inspection
+  attr_reader :data
+
+  # fake a model
+  def initialize
+    @data = DATA
+  end
+
+  # fake a model
+  def offset(start)
+    @data = @data[start..]
+    self
+  end
+
+  # fake a model
+  def limit(count)
+    @data = @data[...count]
+    self
+  end
+
+  def count_by_page
+    3
+  end
+end
+
+class PaginatedTest < ActiveSupport::TestCase
+  def assert_valid_pagination(paginated, count:)
+    assert_equal count, paginated.data.size
+  end
+
+  test "paginated with placeholder" do
+    test_empty_params = FakePaginated.new.paginate({})
+    assert_valid_pagination test_empty_params, count: FakePaginated.new.count_by_page
+    assert_equal %w[a b c], test_empty_params.data
+
+    test_valid_params = FakePaginated.new.paginate({ page: 1 })
+    assert_valid_pagination test_valid_params, count: FakePaginated.new.count_by_page
+    assert_equal %w[d e f], test_valid_params.data
+    test_valid_params = FakePaginated.new.paginate({ page: 4 })
+    assert_valid_pagination test_valid_params, count: FakePaginated.new.count_by_page
+    assert_equal %w[m n o], test_valid_params.data
+
+    test_invalid_params = FakePaginated.new.paginate({ page: "what" })
+    assert_valid_pagination test_invalid_params, count: FakePaginated.new.count_by_page
+    assert_equal %w[a b c], test_invalid_params.data
+  end
+end

test/test_helper.rb

   fixtures :all
 
   # Add more helper methods to be used by all tests here...
-end
+end