From https://once.com/writebook

test/models/leaf/editable_test.rb

@@ -0,0 +1,66 @@
+require "test_helper"
+
+class Leaf::EditableTest < ActiveSupport::TestCase
+  test "editing a leafable records the edit" do
+    leaves(:welcome_page).edit leafable_params: { body: "New body" }
+
+    assert_equal "New body", leaves(:welcome_page).page.body.content
+
+    assert leaves(:welcome_page).edits.last.revision?
+    assert_equal "This is _such_ a great handbook.", leaves(:welcome_page).edits.last.page.body.content
+  end
+
+  test "edits that are close together don't create new revisions" do
+    assert_difference -> { leaves(:welcome_page).edits.count }, +1 do
+      leaves(:welcome_page).edit leafable_params: { body: "First change" }
+    end
+
+    freeze_time
+    travel 1.minute
+
+    assert_no_difference -> { leaves(:welcome_page).edits.count } do
+      leaves(:welcome_page).edit leafable_params: { body: "Second change" }
+    end
+
+    assert_equal "Second change", leaves(:welcome_page).page.body.content
+    assert_equal Time.now, leaves(:welcome_page).edits.last.updated_at
+
+    travel 1.hour
+
+    assert_difference -> { leaves(:welcome_page).edits.count }, +1 do
+      leaves(:welcome_page).edit leafable_params: { body: "Third change" }
+    end
+  end
+
+  test "changing a leaf title doesn't create a revision" do
+    assert_no_difference -> { Edit.count } do
+      leaves(:welcome_page).edit leaf_params: { title: "New title" }
+    end
+
+    assert_equal "New title", leaves(:welcome_page).title
+  end
+
+  test "changes that don't affect the leafable don't create a revision" do
+    assert_no_difference -> { Edit.count } do
+      leaves(:welcome_page).edit leafable_params: {}
+    end
+  end
+
+  test "editing a leafable with an attachment includes the attachments in the new version" do
+    assert leaves(:reading_picture).picture.image.attached?
+
+    leaves(:reading_picture).edit leaf_params: { title: "New title" }
+
+    assert_equal "New title", leaves(:reading_picture).title
+    assert leaves(:reading_picture).picture.image.attached?
+  end
+
+  test "trashing a leaf records the edit" do
+    leaves(:welcome_page).trashed!
+
+    assert leaves(:welcome_page).trashed?
+
+    assert leaves(:welcome_page).edits.last.trash?
+    assert_equal "This is _such_ a great handbook.", leaves(:welcome_page).edits.last.page.body.content
+  end
+end

test/models/leaf/positionable_test.rb

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+require "test_helper"
+
+class Leaf::PositionableTest < ActiveSupport::TestCase
+  setup do
+    @leaves = books(:handbook).leaves.positioned
+  end
+
+  test "items are sorted in positioned order" do
+    assert_equal [ leaves(:welcome_section), leaves(:welcome_page), leaves(:summary_page), leaves(:reading_picture) ], @leaves
+  end
+
+  test "items can be moved earlier" do
+    leaves(:welcome_page).move_to_position(0)
+
+    assert_equal [ leaves(:welcome_page), leaves(:welcome_section), leaves(:summary_page), leaves(:reading_picture) ], @leaves.reload
+  end
+
+  test "items can be moved beyond the start, which puts them at the start" do
+    leaves(:welcome_page).move_to_position(-99)
+
+    assert_equal [ leaves(:welcome_page), leaves(:welcome_section), leaves(:summary_page), leaves(:reading_picture) ], @leaves.reload
+  end
+
+  test "items can be moved later" do
+    leaves(:welcome_section).move_to_position(2)
+
+    assert_equal [ leaves(:welcome_page), leaves(:summary_page), leaves(:welcome_section), leaves(:reading_picture) ], @leaves.reload
+  end
+
+  test "items can be moved beyond the end, which puts them at the end" do
+    leaves(:welcome_section).move_to_position(99)
+
+    assert_equal [ leaves(:welcome_page), leaves(:summary_page), leaves(:reading_picture), leaves(:welcome_section) ], @leaves.reload
+  end
+
+  test "items can be moved to their existing position" do
+    leaves(:welcome_page).move_to_position(1)
+
+    assert_equal [ leaves(:welcome_section), leaves(:welcome_page), leaves(:summary_page), leaves(:reading_picture) ], @leaves.reload
+  end
+
+  test "items can be moved in blocks" do
+    leaves(:welcome_section).move_to_position(1, followed_by: [ leaves(:welcome_page), leaves(:summary_page) ])
+
+    assert_equal [ leaves(:reading_picture), leaves(:welcome_section), leaves(:welcome_page), leaves(:summary_page) ], @leaves.reload
+  end
+
+  test "new items are inserted at the end" do
+    new_page = books(:handbook).press Page.new(body: "New Page"), title: "New Page"
+
+    assert_equal new_page, books(:handbook).leaves.positioned.last
+  end
+
+  test "the first item in the collection has the expected score" do
+    books(:handbook).leaves.destroy_all
+    new_page = books(:handbook).press Page.new(body: "New Page"), title: "New Page"
+
+    assert_equal 1, new_page.position_score
+  end
+
+  test "positioning is rebalanced when necessary" do
+    leaves(:welcome_section).update!(position_score: 1e-11)
+    leaves(:welcome_page).update!(position_score: 2e-11)
+
+    leaves(:summary_page).move_to_position(1)
+
+    assert_equal leaves(:summary_page), @leaves.reload.second
+    assert_equal [ 1, 2, 3, 4 ], @leaves.pluck(:position_score)
+  end
+
+  test "items know their neighbours" do
+    assert_equal leaves(:welcome_section), leaves(:welcome_page).previous
+    assert_equal leaves(:summary_page), leaves(:welcome_page).next
+
+    assert_nil leaves(:welcome_section).previous
+    assert_nil leaves(:reading_picture).next
+  end
+
+  test "only active items are included as neighbours" do
+    assert_equal leaves(:summary_page), leaves(:welcome_page).next
+
+    leaves(:summary_page).trashed!
+
+    assert_equal leaves(:reading_picture), leaves(:welcome_page).next
+  end
+
+  test "only active items are counted when determining position" do
+    leaves(:welcome_page).trashed!
+
+    leaves(:welcome_section).move_to_position(1)
+    assert_equal [ leaves(:summary_page), leaves(:welcome_section), leaves(:reading_picture) ], @leaves.reload.active
+
+    leaves(:welcome_section).move_to_position(0)
+    assert_equal [ leaves(:welcome_section), leaves(:summary_page), leaves(:reading_picture) ], @leaves.reload.active
+  end
+end