diff --git a/lib/dz.rb b/lib/dz.rb
index a6b5061..b7bad59 100644
--- a/lib/dz.rb
+++ b/lib/dz.rb
@@ -8,7 +8,7 @@ def version
     end
 
     def dz2bin(s)
-      hxs = s.gsub(/^#.*?$/, ' ').split(/[^0-9A-Fa-f]/)
+      hxs = s.gsub(/#.*?$/, ' ').split(/[^0-9A-Fa-f]/m)
       hxs.reject!(&:empty?)
 
       hxs.map { |x| x.to_i(16) }.pack('C*')
diff --git a/tests/dz2bin_tests.rb b/tests/dz2bin_tests.rb
index 6254e89..64964f4 100644
--- a/tests/dz2bin_tests.rb
+++ b/tests/dz2bin_tests.rb
@@ -3,6 +3,59 @@
 
 class DZ_dz2bin_test < Test::Unit::TestCase
 
-  # TODO
+  # to_bytes("AABBCC") -> "\xAA\xBB\xCC"
+  def to_bytes(b)
+    [b].pack('H*')
+  end
+
+  def test_empty_string
+    assert_equal('', DZ.dz2bin(''))
+  end
+
+  def test_only_a_comment
+    assert_equal('', DZ.dz2bin('#'))
+    assert_equal('', DZ.dz2bin('# foo'))
+    assert_equal('', DZ.dz2bin('   # foo'))
+  end
+
+  def test_empty_lines
+    assert_equal('', DZ.dz2bin("\n\n\n"))
+  end
+
+  def test_no_hexa
+    assert_equal('', DZ.dz2bin("lol\n# something\n | ---- $<%"))
+  end
+
+  def test_one_byte
+    assert_equal(to_bytes('00'), DZ.dz2bin('00'))
+    assert_equal(to_bytes('42'), DZ.dz2bin('42'))
+    assert_equal(to_bytes('AF'), DZ.dz2bin('AF'))
+    assert_equal(to_bytes('FF'), DZ.dz2bin('FF'))
+  end
+
+  def test_two_bytes
+    assert_equal(to_bytes('0000'), DZ.dz2bin('00 00'))
+    assert_equal(to_bytes('4237'), DZ.dz2bin('42 37'))
+    assert_equal(to_bytes('AF10'), DZ.dz2bin('AF 10'))
+    assert_equal(to_bytes('FFDC'), DZ.dz2bin('FF DC'))
+  end
+
+  def test_two_bytes_stuff_between
+    assert_equal(to_bytes('0000'), DZ.dz2bin('00 x 00'))
+    assert_equal(to_bytes('4237'), DZ.dz2bin('42 $$ 37'))
+    assert_equal(to_bytes('AF10'), DZ.dz2bin('AF **** 10'))
+    assert_equal(to_bytes('FFDC'), DZ.dz2bin('FF <!---> DC'))
+  end
+
+  def test_two_bytes_different_lines
+    assert_equal(to_bytes('4237'), DZ.dz2bin("42\n37"))
+  end
+
+  def test_multiple_bytes
+    assert_equal(to_bytes('4237AB'), DZ.dz2bin(%q[
+        42 # <-- here is 42
+        37 |-------| AB
+    ]))
+  end
 
 end
diff --git a/tests/tests.rb b/tests/tests.rb
index 1c5e6c7..97572b8 100755
--- a/tests/tests.rb
+++ b/tests/tests.rb
@@ -12,7 +12,7 @@
 SimpleCov.formatter = Coveralls::SimpleCov::Formatter
 SimpleCov.start { add_filter '/tests/' }
 
-require 'dz'
+require_relative '../lib/dz'
 
 for t in Dir.glob( File.join( test_dir,  '*_tests.rb' ) )
   require t