Add test for String#lstrip!

* test/ruby/test_string.rb (TestString#test_lstrip_bang): Add test
  for String#lstrip!.  [Fix GH-1176]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53352 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Dec 28 09:18:53 2015  Kuniaki IGARASHI  <igaiga@gmail.com>
+
+	* test/ruby/test_string.rb (TestString#test_lstrip_bang): Add test
+	  for String#lstrip!.  [Fix GH-1176]
+
 Sun Dec 27 23:32:26 2015  Masaki Suketa <masaki.suketa@nifty.ne.jp>
 
 	* ext/win32ole/win32ole.c (ole_variant2val): refactoring.

test/ruby/test_string.rb

@@ -2147,6 +2147,20 @@ class TestString < Test::Unit::TestCase
     assert_equal("\u3042", "   \u3042".lstrip)
   end
 
+  def test_lstrip_bang
+    s1 = S("  hello  ")
+    assert_equal("hello  ", s1.lstrip!)
+    assert_equal("hello  ", s1)
+
+    s2 = S("\u3042  ")
+    assert_equal(nil, s2.lstrip!)
+    assert_equal("\u3042  ", s2)
+
+    s3 = S("  \u3042")
+    assert_equal("\u3042", s3.lstrip!)
+    assert_equal("\u3042", s3)
+  end
+
 =begin
   def test_symbol_table_overflow
     assert_in_out_err([], <<-INPUT, [], /symbol table overflow \(symbol [a-z]{8}\) \(RuntimeError\)/)