diff --git a/ChangeLog b/ChangeLog
index 20cdcdf7b1..bfaa054a9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Nov 30 12:30:55 2012  Akinori MUSHA  <knu@iDaemons.org>
+
+	* test/test_abbrev.rb: Add tests for lib/abbrev.rb.
+
 Fri Nov 30 12:27:51 2012  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/rubygems/spec_fetcher.rb:  Allow prerelease spec fetching to fail
diff --git a/test/test_abbrev.rb b/test/test_abbrev.rb
new file mode 100644
index 0000000000..3cf1acfb05
--- /dev/null
+++ b/test/test_abbrev.rb
@@ -0,0 +1,49 @@
+require 'test/unit'
+require 'abbrev'
+
+class TestAbbrev < Test::Unit::TestCase
+  def test_abbrev
+    words = %w[summer winter ruby rules]
+
+    assert_equal({
+        "rub"    => "ruby",
+        "ruby"   => "ruby",
+        "rul"    => "rules",
+        "rule"   => "rules",
+        "rules"  => "rules",
+        "s"      => "summer",
+        "su"     => "summer",
+        "sum"    => "summer",
+        "summ"   => "summer",
+        "summe"  => "summer",
+        "summer" => "summer",
+        "w"      => "winter",
+        "wi"     => "winter",
+        "win"    => "winter",
+        "wint"   => "winter",
+        "winte"  => "winter",
+        "winter" => "winter",
+      }, words.abbrev)
+
+    assert_equal({
+        "rub"    => "ruby",
+        "ruby"   => "ruby",
+        "rul"    => "rules",
+        "rule"   => "rules",
+        "rules"  => "rules",
+      }, words.abbrev('ru'))
+
+    assert_equal words.abbrev,       Abbrev.abbrev(words)
+    assert_equal words.abbrev('ru'), Abbrev.abbrev(words, 'ru')
+  end
+
+  def test_abbrev_lf
+    assert_equal({
+        "abc"     => "abc",
+        "abc\n"   => "abc\nd",
+        "abc\nd"  => "abc\nd",
+        "d"       => "de",
+        "de"      => "de",
+      }, Abbrev.abbrev(["abc", "abc\nd", "de"]))
+  end
+end