resolves #3006 fix deprecated ERB trim mode (PR #3007)

- use 0 instead of <
- augment test to verify behavior of trim mode
- remove encoding setting from ERB template

5 files changed, 24 insertions, 3 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 2521f48f..48c1dc92 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -41,6 +41,7 @@ Bug Fixes::
   * scope constant lookups (#2764)
   * use byteslice instead of slice to remove BOM from string (#2764)
   * Reader#push_include should not fail if data is nil
+  * fix deprecated ERB trim mode that was causing warning (#3006)
 
 Build / Infrastructure::
 
diff --git a/lib/asciidoctor/converter/template.rb b/lib/asciidoctor/converter/template.rb
index dc0af224..493feeb1 100644
--- a/lib/asciidoctor/converter/template.rb
+++ b/lib/asciidoctor/converter/template.rb
@@ -25,7 +25,7 @@ module Asciidoctor
   # will be issued.
   class Converter::TemplateConverter < Converter::Base
     DEFAULT_ENGINE_OPTIONS = {
-      erb: { trim: '<' },
+      erb: { trim: 0 },
       # TODO line 466 of haml/compiler.rb sorts the attributes; file an issue to make this configurable
       # NOTE AsciiDoc syntax expects HTML/XML output to use double quotes around attribute values
       haml: { format: :xhtml, attr_wrapper: '"', escape_attrs: false, ugly: true },
diff --git a/test/converter_test.rb b/test/converter_test.rb
index 53829434..0ceedf15 100644
--- a/test/converter_test.rb
+++ b/test/converter_test.rb
@@ -225,7 +225,8 @@ Sidebar content
     end
 
     test 'should load ERB templates using ERBTemplate if eruby is not set' do
-      doc = Asciidoctor::Document.new [], template_dir: (fixture_path 'custom-backends/erb'), template_cache: false
+      input = %([.wrapper]\n--\nfoobar\n--)
+      doc = Asciidoctor::Document.new input, template_dir: (fixture_path 'custom-backends/erb'), template_cache: false
       assert_kind_of Asciidoctor::Converter::CompositeConverter, doc.converter
       ['paragraph'].each do |node_name|
         selected = doc.converter.find_converter node_name
@@ -236,6 +237,17 @@ Sidebar content
         assert_kind_of ::ERB, template.instance_variable_get('@engine')
         assert_equal %(block_#{node_name}.html.erb), File.basename(selected.templates[node_name].file)
       end
+      # NOTE verify behavior of trim mode
+      expected_output = <<-EOS.chomp
+<div class="openblock wrapper">
+<div class="content">
+<div class="paragraph">
+<p>foobar</p>
+</div>
+</div>
+</div>
+      EOS
+      assert_equal expected_output, doc.convert
     end
 
     test 'should load ERB templates using ErubisTemplate if eruby is set to erubis' do
diff --git a/test/fixtures/custom-backends/erb/html5/block_paragraph.html.erb b/test/fixtures/custom-backends/erb/html5/block_paragraph.html.erb
index 7eb80950..eaaef93c 100644
--- a/test/fixtures/custom-backends/erb/html5/block_paragraph.html.erb
+++ b/test/fixtures/custom-backends/erb/html5/block_paragraph.html.erb
@@ -1,4 +1,4 @@
-<%#encoding:UTF-8%><div<%= @id && %( id="#{@id}") %> class="<%= ['paragraph',role].compact * ' ' %>"><%
+<div<%= @id && %( id="#{@id}") %> class="<%= ['paragraph',role].compact * ' ' %>"><%
 if title? %>
 <div class="title"><%= title %></div><%
 end %>
diff --git a/test/fixtures/custom-backends/erb/html5/open.html.erb b/test/fixtures/custom-backends/erb/html5/open.html.erb
new file mode 100644
index 00000000..ca738ed7
--- /dev/null
+++ b/test/fixtures/custom-backends/erb/html5/open.html.erb
@@ -0,0 +1,8 @@
+<div<%= @id && %( id="#{@id}") %> class="<%= ['openblock',(@style == 'open' ? nil : @style),role].compact * ' ' %>"><%
+  if title? %>
+<div class="title"><%= title %></div><%
+  end %>
+<div class="content">
+<%= content %>
+</div>
+</div>