Added more tests for the convert_listing() method.

test/test_listing.rb

@@ -30,6 +30,7 @@ def test_listing_block_title
     EOF
 
     assert_xpath_equal xml, 'A listing block title', '//p[@outputclass="title"]/b/text()'
+    assert_xpath_equal xml, 'A listing block', '//codeblock/text()'
   end
 
   def test_explicit_source_block
@@ -41,25 +42,28 @@ def test_explicit_source_block
     assert_xpath_equal xml, 'A source code block', '//codeblock/text()'
   end
 
-  def test_delimited_source_block
+  def test_implied_source_block
     xml = <<~EOF.chomp.to_dita
+    [,ruby]
     ----
-    A source code block
+    puts "Hello"
     ----
     EOF
 
-    assert_xpath_equal xml, 'A source code block', '//codeblock/text()'
+    assert_xpath_equal xml, 'puts "Hello"', '//codeblock/text()'
   end
 
-  def test_implied_source_block
+  def test_source_block_title
     xml = <<~EOF.chomp.to_dita
-    [,ruby]
+    .A source block title
+    [source]
     ----
-    puts "Hello"
+    A source block
     ----
     EOF
 
-    assert_xpath_equal xml, 'puts "Hello"', '//codeblock/text()'
+    assert_xpath_equal xml, 'A source block title', '//p[@outputclass="title"]/b/text()'
+    assert_xpath_equal xml, 'A source block', '//codeblock/text()'
   end
 
   def test_source_block_language