resolves asciidoctor#1795 don't insert page break between part and fi…

…rst chapter if heading-part-break-after key in theme is avoid

CHANGELOG.adoc

@@ -12,6 +12,7 @@ Enhancements::
 * add `save_theme` helper to work with a copy of the theme within a scope (#2196)
 * add support for `scale` attribute or `iw` unit on `pdfwidth` attribute on image macros (#1933)
 * add backlink from bibref on bibliography entry to first reference to that entry in the document (#1737)
+* don't insert page break between part and first chapter if `heading-part-break-after` key in theme is `avoid` (#1795)
 
 == 2.0.8 (2022-06-08) - @mojavelinux
 

docs/modules/theme/pages/heading.adoc

@@ -286,7 +286,7 @@ The doctype must be `book` for the `heading-part` keys to take effect.
 |Key |Value Type |Example
 
 |break-after
-|`always` {vbar} `auto` +
+|`always` {vbar} `avoid` {vbar} `auto` +
 (default: `auto`)
 |[source]
 heading:

spec/section_spec.rb

@@ -1185,6 +1185,24 @@
     (expect part2_text[:page_number]).to be 4
   end
 
+  it 'should not add page break after part if heading-part-break-after key in theme is avoid' do
+    pdf = to_pdf <<~'EOS', pdf_theme: { heading_part_break_after: 'avoid' }, analyze: true
+    = Document Title
+    :doctype: book
+
+    = Part I
+
+    == Chapter in Part I
+    EOS
+
+    (expect pdf.pages).to have_size 2
+    part1_text = (pdf.find_text 'Part I')[0]
+    chapter1_text = (pdf.find_text 'Chapter in Part I')[0]
+    (expect part1_text[:page_number]).to be 2
+    (expect chapter1_text[:page_number]).to be 2
+    (expect part1_text[:y] - chapter1_text[:y]).to be < 50
+  end
+
   it 'should support abstract defined as special section' do
     pdf = to_pdf <<~'EOS', analyze: true
     = Document Title