1 files changed, 18 insertions, 0 deletions
diff --git a/test/-ext-/string/test_capacity.rb b/test/-ext-/string/test_capacity.rb
new file mode 100644
index 0000000000..b4e4fb7c02
--- /dev/null
+++ b/test/-ext-/string/test_capacity.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+require 'test/unit'
+require '-test-/string'
+
+class Test_StringCapacity < Test::Unit::TestCase
+  def test_capacity_embeded
+    size = RbConfig::SIZEOF['void*'] * 3 - 1
+    assert_equal size, Bug::String.capacity('foo')
+  end
+
+  def test_capacity_shared
+    assert_equal 0, Bug::String.capacity(:abcdefghijklmnopqrstuvwxyz.to_s)
+  end
+
+  def test_capacity_normal
+    assert_equal 128, Bug::String.capacity('1'*128)
+  end
+end