2 files changed, 28 insertions, 3 deletions
diff --git a/test/-ext-/string/test_capacity.rb b/test/-ext-/string/test_capacity.rb
index 54f3caf32e..48d2deadee 100644
--- a/test/-ext-/string/test_capacity.rb
+++ b/test/-ext-/string/test_capacity.rb
@@ -4,16 +4,29 @@ require '-test-/string'
 require 'rbconfig/sizeof'
 
 class Test_StringCapacity < Test::Unit::TestCase
+  def capa(str)
+    Bug::String.capacity(str)
+  end
+
   def test_capacity_embeded
     size = RbConfig::SIZEOF['void*'] * 3 - 1
-    assert_equal size, Bug::String.capacity('foo')
+    assert_equal size, capa('foo')
   end
 
   def test_capacity_shared
-    assert_equal 0, Bug::String.capacity(:abcdefghijklmnopqrstuvwxyz.to_s)
+    assert_equal 0, capa(:abcdefghijklmnopqrstuvwxyz.to_s)
   end
 
   def test_capacity_normal
-    assert_equal 128, Bug::String.capacity('1'*128)
+    assert_equal 128, capa('1'*128)
+  end
+
+  def test_s_new_capacity
+    assert_equal("", String.new(capacity: 1000))
+    assert_equal(String, String.new(capacity: 1000).class)
+    assert_equal(10000, capa(String.new(capacity: 10000)))
+
+    assert_equal("", String.new(capacity: -1000))
+    assert_equal(capa(String.new(capacity: -10000)), capa(String.new(capacity: -1000)))
   end
 end
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index f1633e3d7b..339e8728ab 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -45,6 +45,18 @@ class TestString < Test::Unit::TestCase
     src.force_encoding("euc-jp")
     assert_equal(src, S(src, encoding: "utf-8"))
     assert_equal(Encoding::UTF_8, S(src, encoding: "utf-8").encoding)
+
+    assert_equal("", S(capacity: 1000))
+    assert_equal(Encoding::ASCII_8BIT, S(capacity: 1000).encoding)
+
+    assert_equal("", S(capacity: 1000, encoding: "euc-jp"))
+    assert_equal(Encoding::EUC_JP, S(capacity: 1000, encoding: "euc-jp").encoding)
+
+    assert_equal("", S("", capacity: 1000))
+    assert_equal(__ENCODING__, S("", capacity: 1000).encoding)
+
+    assert_equal("", S("", capacity: 1000, encoding: "euc-jp"))
+    assert_equal(Encoding::EUC_JP, S("", capacity: 1000, encoding: "euc-jp").encoding)
   end
 
   def test_AREF # '[]'