resolves #2003 compute extent of content in scratch document to arrange content block in primary document

* introduce arrange_block helper to handle positioning content block in primary document
* reimplement new dry_run to compute the extent and start position of the content block instead of just the height
* stop rendering at page boundary in scratch document when computing start position of content block to avoid unnecessary work
* ensure that caption stays with start of content block when arranging content block
* prevent arrange_block from starting content block on page when no content from block fits on that page
* avoid converting content that overruns page in AsciiDoc table cell in scratch document
* encapsulate push/pop scratch in arrange_block
* add tests for the arrange_block helper
* prevent nested breakable blocks from flowing beyond first page when performing on single page only
* switch dry_run method to accept keyword arguments
* avoid arrange_block when converting open block when possible
* include negative tests for image taller than page at top of block
* verify borders and backgrounds are not drawn in scratch document
* add test to verify behavior of stop_if_first_page_empty
* include sanity check before drawing background and border over extent
* add rdoc to dry_run and arrange_block help methods
* reuse computed extent as TOC extent
* remove unused code
* raise error if table caption does not fit on single page
* add test that footnotes are not pushed down if height exceeds height of page

1 files changed, 65 insertions, 0 deletions

diff --git a/spec/open_spec.rb b/spec/open_spec.rb
index d24b5e24..2f790751 100644
--- a/spec/open_spec.rb
+++ b/spec/open_spec.rb
@@ -3,6 +3,23 @@
 require_relative 'spec_helper'
 
 describe 'Asciidoctor::PDF::Converter - Open' do
+  it 'should be breakable by default', breakable: true do
+    with_content_spacer 10, 720 do |spacer_path|
+      pdf = to_pdf <<~EOS, analyze: true
+      image::#{spacer_path}[]
+
+      --
+      first page
+
+      second page
+      --
+      EOS
+      (expect pdf.pages).to have_size 2
+      (expect (pdf.find_unique_text 'first page')[:page_number]).to be 1
+      (expect (pdf.find_unique_text 'second page')[:page_number]).to be 2
+    end
+  end
+
   it 'should keep block together when it has the unbreakable option', visual: true do
     to_file = to_pdf_file <<~EOS, 'open-unbreakable-option-fit.pdf'
     Make it rain.footnote:[money]
@@ -86,4 +103,52 @@ describe 'Asciidoctor::PDF::Converter - Open' do
     (expect (pdf.find_unique_text 'content')[:page_number]).to be 2
     (expect (pdf.find_unique_text 'Title')[:page_number]).to be 2
   end
+
+  it 'should not dry run block unless necessary' do
+    calls = []
+    extensions = proc do
+      block :spy do
+        on_context :paragraph
+        process do |parent, reader, attrs|
+          block = create_paragraph parent, reader.lines, attrs
+          block.instance_variable_set :@_calls, calls
+          block.extend (Module.new do
+            def content
+              @_calls << (caller.join ?\n) if document.converter.scratch? # rubocop:disable RSpec/InstanceVariable
+              super
+            end
+          end)
+        end
+      end
+    end
+
+    {
+      '' => false,
+      %(.title) => false,
+      %([#idname]) => false,
+      %([%unbreakable]) => false,
+      %(before\n) => false,
+      %(before\n\n.title) => true,
+      %(before\n\n[#idname]) => true,
+      %(before\n\n[%unbreakable]) => true,
+    }.each do |before_block, dry_run|
+      input = <<~EOS.lstrip
+      #{before_block}
+      --
+      #{['block content'] * 4 * %(\n\n)}
+
+      [spy]
+      block content
+      --
+      EOS
+      pdf = to_pdf input, extensions: extensions, analyze: true
+      (expect pdf.pages).to have_size 1
+      (expect (pdf.find_text 'block content')[0][:page_number]).to be 1
+      if dry_run
+        (expect calls).not_to be_empty
+      else
+        (expect calls).to be_empty
+      end
+    end
+  end
 end