1 files changed, 65 insertions, 0 deletions
diff --git a/spec/ruby/command_line/dash_upper_k_spec.rb b/spec/ruby/command_line/dash_upper_k_spec.rb
new file mode 100644
index 0000000000..7e71532295
--- /dev/null
+++ b/spec/ruby/command_line/dash_upper_k_spec.rb
@@ -0,0 +1,65 @@
+require_relative '../spec_helper'
+
+describe 'The -K command line option' do
+  before :each do
+    @test_string = "print [__ENCODING__&.name, Encoding.default_external&.name, Encoding.default_internal&.name].inspect"
+  end
+
+  describe 'sets __ENCODING__ and Encoding.default_external' do
+    it "to Encoding::BINARY with -Ka" do
+      ruby_exe(@test_string, options: '-Ka').should ==
+        [Encoding::BINARY.name, Encoding::BINARY.name, nil].inspect
+    end
+
+    it "to Encoding::BINARY with -KA" do
+      ruby_exe(@test_string, options: '-KA').should ==
+        [Encoding::BINARY.name, Encoding::BINARY.name, nil].inspect
+    end
+
+    it "to Encoding::BINARY with -Kn" do
+      ruby_exe(@test_string, options: '-Kn').should ==
+        [Encoding::BINARY.name, Encoding::BINARY.name, nil].inspect
+    end
+
+    it "to Encoding::BINARY with -KN" do
+      ruby_exe(@test_string, options: '-KN').should ==
+        [Encoding::BINARY.name, Encoding::BINARY.name, nil].inspect
+    end
+
+    it "to Encoding::EUC_JP with -Ke" do
+      ruby_exe(@test_string, options: '-Ke').should ==
+        [Encoding::EUC_JP.name, Encoding::EUC_JP.name, nil].inspect
+    end
+
+    it "to Encoding::EUC_JP with -KE" do
+      ruby_exe(@test_string, options: '-KE').should ==
+        [Encoding::EUC_JP.name, Encoding::EUC_JP.name, nil].inspect
+    end
+
+    it "to Encoding::UTF_8 with -Ku" do
+      ruby_exe(@test_string, options: '-Ku').should ==
+        [Encoding::UTF_8.name, Encoding::UTF_8.name, nil].inspect
+    end
+
+    it "to Encoding::UTF_8 with -KU" do
+      ruby_exe(@test_string, options: '-KU').should ==
+        [Encoding::UTF_8.name, Encoding::UTF_8.name, nil].inspect
+    end
+
+    it "to Encoding::Windows_31J with -Ks" do
+      ruby_exe(@test_string, options: '-Ks').should ==
+        [Encoding::Windows_31J.name, Encoding::Windows_31J.name, nil].inspect
+    end
+
+    it "to Encoding::Windows_31J with -KS" do
+      ruby_exe(@test_string, options: '-KS').should ==
+        [Encoding::Windows_31J.name, Encoding::Windows_31J.name, nil].inspect
+    end
+  end
+
+  it "ignores unknown codes" do
+    external = Encoding.find('external')
+    ruby_exe(@test_string, options: '-KZ').should ==
+      [Encoding::UTF_8.name, external.name, nil].inspect
+  end
+end