Fix tests with libxml2 2.9.12

This patch fixes a number of test issues that started happening after
Ubuntu moved to libmlx2 2.9.12+dfsg-2.  They are:

* num_chars has been deprecated and is now always set to 0.  See
  https://gitlab.gnome.org/GNOME/libxml2/-/commit/438e595a8cccbe48de3a0be2e0c291cfe97080b1.

* The "Fatal error: EndTag..." message has been reverted back to
  "Fatal error: Premature end of data...".

* Some adjustments to the expected values of error.int1, error.int2
  and error.str1.

Closes xml4r#172

Signed-off-by: Sergio Durigan Junior <sergio.durigan@canonical.com>

test/test_parser.rb

@@ -271,7 +271,7 @@ def test_error
     assert_equal('foz', error.str2)
     assert_nil(error.str3)
     assert_equal(1, error.int1)
-    assert_equal(20, error.int2)
+    assert_equal(18, error.int2)
     assert_nil(error.node)
   end
 

test/test_parser_context.rb

@@ -127,12 +127,6 @@ def test_keep_blanks
     end
   end
 
-  if ENV['NOTWORKING']
-    def test_num_chars
-      assert_equal(17, context.num_chars)
-    end
-  end
-
   def test_replace_entities
     context = LibXML::XML::Parser::Context.new
     assert(!context.replace_entities?)
@@ -185,7 +179,7 @@ def test_parse_error
     assert_nil(context.name_node)
     assert_equal(0, context.name_depth)
     assert_equal(10, context.name_depth_max)
-    assert_equal(17, context.num_chars)
+    assert_equal(0, context.num_chars)
     assert_equal(false, context.replace_entities?)
     assert_equal(1, context.space_depth)
     assert_equal(10, context.space_depth_max)

test/test_sax_parser.rb

@@ -254,21 +254,21 @@ def test_parse_error
     assert_equal("start_element: Results, attr: {}", result[i+=1])
     assert_equal("start_element_ns: Results, attr: {}, prefix: , uri: , ns: {}", result[i+=1])
     assert_equal("characters: \n", result[i+=1])
-    assert_equal("error: Fatal error: EndTag: '</' not found at :2.", result[i+=1])
+    assert_equal("error: Fatal error: Premature end of data in tag Results line 1 at :2.", result[i+=1])
     assert_equal("end_document", result[i+=1])
 
     refute_nil(error)
     assert_kind_of(LibXML::XML::Error, error)
-    assert_equal("Fatal error: EndTag: '</' not found at :2.", error.message)
+    assert_equal("Fatal error: Premature end of data in tag Results line 1 at :2.", error.message)
     assert_equal(LibXML::XML::Error::PARSER, error.domain)
-    assert_equal(LibXML::XML::Error::LTSLASH_REQUIRED, error.code)
+    assert_equal(LibXML::XML::Error::TAG_NOT_FINISHED, error.code)
     assert_equal(LibXML::XML::Error::FATAL, error.level)
     assert_nil(error.file)
     assert_equal(2, error.line)
-    assert_nil(error.str1)
+    refuse_nil(error.str1)
     assert_nil(error.str2)
     assert_nil(error.str3)
-    assert_equal(0, error.int1)
+    assert_equal(1, error.int1)
     assert_equal(1, error.int2)
     assert_nil(error.node)
   end