diff --git a/lib/pdd/sources.rb b/lib/pdd/sources.rb
index a5c1354..87c6f96 100644
--- a/lib/pdd/sources.rb
+++ b/lib/pdd/sources.rb
@@ -57,13 +57,17 @@ def exclude(ptn)
 
     private
 
-    def binary?(f)
+    # @todo #98:30min Change the implementation of this method
+    #  to also work in Windows machines. Investigate the possibility
+    #  of use a gem for this. After that, remove the skip of the test
+    #  `test_ignores_binary_files` in `test_sources.rb`.
+    def binary?(file)
       return false if Gem.win_platform?
-      `grep -qI '.' #{Shellwords.escape(f)}`
+      `grep -qI '.' #{Shellwords.escape(file)}`
       if $CHILD_STATUS.success?
         false
       else
-        PDD.log.info "#{f} is a binary file (#{File.size(f)} bytes)"
+        PDD.log.info "#{file} is a binary file (#{File.size(file)} bytes)"
         true
       end
     end
diff --git a/test/test_source.rb b/test/test_source.rb
index 782f808..20c4fc6 100644
--- a/test/test_source.rb
+++ b/test/test_source.rb
@@ -28,16 +28,14 @@
 # Copyright:: Copyright (c) 2014-2018 Yegor Bugayenko
 # License:: MIT
 class TestSource < Minitest::Test
-  # @todo #85:30min Make this test pass on AppVeyor.
   def test_parsing
-    skip('Skipped because it fails on AppVeyor')
     Dir.mktmpdir 'test' do |dir|
       file = File.join(dir, 'a.txt')
       File.write(
         file,
         "
         * \x40todo #44 привет,
-        *  how are you\t\r\tdoing?
+        *  how are you\t\tdoing?
         * -something else
         Something else
         ~~ \x40todo #ABC-3 this is another puzzle
@@ -90,7 +88,6 @@ def test_failing_on_incomplete_puzzle
   end
 
   def test_failing_on_broken_unicode
-    skip if Gem.win_platform?
     Dir.mktmpdir 'test' do |dir|
       file = File.join(dir, 'xx.txt')
       File.write(file, ' * \x40todo #44 this is a broken unicode: ' + 0x92.chr)
@@ -101,7 +98,6 @@ def test_failing_on_broken_unicode
   end
 
   def test_failing_on_invalid_puzzle_without_hash_sign
-    skip('doesnt work now')
     Dir.mktmpdir 'test' do |dir|
       file = File.join(dir, 'a.txt')
       File.write(
@@ -113,7 +109,7 @@ def test_failing_on_invalid_puzzle_without_hash_sign
       error = assert_raises PDD::Error do
         PDD::VerboseSource.new(file, PDD::Source.new(file, 'hey')).puzzles
       end
-      assert !error.message.index('Incorrect format').nil?
+      assert !error.message.index('is not followed by a puzzle marker').nil?
     end
   end