1 files changed, 27 insertions, 4 deletions
diff --git a/spec/ruby/optional/capi/encoding_spec.rb b/spec/ruby/optional/capi/encoding_spec.rb
index 36437cc7b6..b0c38d75a9 100644
--- a/spec/ruby/optional/capi/encoding_spec.rb
+++ b/spec/ruby/optional/capi/encoding_spec.rb
@@ -2,7 +2,7 @@
 require_relative 'spec_helper'
 require_relative 'fixtures/encoding'
 
-load_extension('encoding')
+extension_path = load_extension('encoding')
 
 describe :rb_enc_get_index, shared: true do
   it "returns the index of the encoding of a String" do
@@ -559,19 +559,19 @@ describe "C-API Encoding function" do
 
   describe "rb_ascii8bit_encindex" do
     it "returns an index for the ASCII-8BIT encoding" do
-      @s.rb_ascii8bit_encindex().should >= 0
+      @s.rb_ascii8bit_encindex().should == 0
     end
   end
 
   describe "rb_utf8_encindex" do
     it "returns an index for the UTF-8 encoding" do
-      @s.rb_utf8_encindex().should >= 0
+      @s.rb_utf8_encindex().should == 1
     end
   end
 
   describe "rb_usascii_encindex" do
     it "returns an index for the US-ASCII encoding" do
-      @s.rb_usascii_encindex().should >= 0
+      @s.rb_usascii_encindex().should == 2
     end
   end
 
@@ -721,4 +721,27 @@ describe "C-API Encoding function" do
       str.bytes.should == [0, 0x24]
     end
   end
+
+  describe "rb_define_dummy_encoding" do
+    it "defines the dummy encoding" do
+      @s.rb_define_dummy_encoding("FOO")
+      enc = Encoding.find("FOO")
+      enc.should.dummy?
+    end
+
+    it "returns the index of the dummy encoding" do
+      index = @s.rb_define_dummy_encoding("BAR")
+      index.should == Encoding.list.size - 1
+    end
+
+    ruby_version_is "3.2" do
+      it "raises EncodingError if too many encodings" do
+        code = <<-RUBY
+          require #{extension_path.dump}
+          1_000.times {|i| CApiEncodingSpecs.new.rb_define_dummy_encoding("R_\#{i}") }
+        RUBY
+        ruby_exe(code, args: "2>&1", exit_status: 1).should.include?('too many encoding (> 256) (EncodingError)')
+      end
+    end
+  end
 end