1 files changed, 27 insertions, 0 deletions
diff --git a/spec/ruby/core/string/start_with_spec.rb b/spec/ruby/core/string/start_with_spec.rb
new file mode 100644
index 0000000000..35e33b46a6
--- /dev/null
+++ b/spec/ruby/core/string/start_with_spec.rb
@@ -0,0 +1,27 @@
+# -*- encoding: utf-8 -*-
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require_relative '../../shared/string/start_with'
+
+describe "String#start_with?" do
+  it_behaves_like :start_with, :to_s
+
+  # Here and not in the shared examples because this is invalid as a Symbol
+  it "matches part of a character with the same part" do
+    "\xA9".should.start_with?("\xA9") # A9 is not a character head for UTF-8
+  end
+
+  ruby_version_is ""..."3.3" do
+    it "does not check we are matching only part of a character" do
+      "\xe3\x81\x82".size.should == 1
+      "\xe3\x81\x82".should.start_with?("\xe3")
+    end
+  end
+
+  ruby_version_is "3.3" do # #19784
+    it "checks we are matching only part of a character" do
+      "\xe3\x81\x82".size.should == 1
+      "\xe3\x81\x82".should_not.start_with?("\xe3")
+    end
+  end
+end