3 files changed, 18 insertions, 13 deletions
diff --git a/spec/ruby/core/string/inspect_spec.rb b/spec/ruby/core/string/inspect_spec.rb
index 8ddbae132a..e63d89ead5 100644
--- a/spec/ruby/core/string/inspect_spec.rb
+++ b/spec/ruby/core/string/inspect_spec.rb
@@ -319,6 +319,10 @@ describe "String#inspect" do
     0.chr.inspect.should == '"\\x00"'
   end
 
+  it "uses \\x notation for broken UTF-8 sequences" do
+    "\xF0\x9F".inspect.should == '"\\xF0\\x9F"'
+  end
+
   describe "when default external is UTF-8" do
     before :each do
       @extenc, Encoding.default_external = Encoding.default_external, Encoding::UTF_8
diff --git a/spec/ruby/core/string/modulo_spec.rb b/spec/ruby/core/string/modulo_spec.rb
index a16112bf44..35ee0b16f5 100644
--- a/spec/ruby/core/string/modulo_spec.rb
+++ b/spec/ruby/core/string/modulo_spec.rb
@@ -1,8 +1,22 @@
 require_relative '../../spec_helper'
+require_relative '../kernel/shared/sprintf'
+require_relative '../kernel/shared/sprintf_encoding'
 require_relative 'fixtures/classes'
 require_relative '../../shared/hash/key_error'
 
 describe "String#%" do
+  it_behaves_like :kernel_sprintf, -> format, *args {
+    format % args
+  }
+
+  it_behaves_like :kernel_sprintf_encoding, -> format, *args {
+    format % args
+  }
+end
+
+# TODO: these specs are mostly redundant with kernel/shared/sprintf.rb specs.
+# These specs should be moved there and deduplicated.
+describe "String#%" do
   context "when key is missing from passed-in hash" do
     it_behaves_like :key_error, -> obj, key { "%{#{key}}" % obj }, { a: 5 }
   end
diff --git a/spec/ruby/core/string/percent_spec.rb b/spec/ruby/core/string/percent_spec.rb
deleted file mode 100644
index e3460522b1..0000000000
--- a/spec/ruby/core/string/percent_spec.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-require_relative '../../spec_helper'
-require_relative '../kernel/shared/sprintf'
-require_relative '../kernel/shared/sprintf_encoding'
-
-describe "String#%" do
-  it_behaves_like :kernel_sprintf, -> format, *args {
-    format % args
-  }
-
-  it_behaves_like :kernel_sprintf_encoding, -> format, *args {
-    format % args
-  }
-end