Ensure test suite is compatible with --frozen-string-literal

As preparation for https://bugs.ruby-lang.org/issues/20205
making sure the test suite is compatible with frozen string
literals is making things easier.

2 files changed, 11 insertions, 11 deletions

diff --git a/test/ruby/enc/test_case_mapping.rb b/test/ruby/enc/test_case_mapping.rb
index 31acdc4331..a7d1ed0d16 100644
--- a/test/ruby/enc/test_case_mapping.rb
+++ b/test/ruby/enc/test_case_mapping.rb
@@ -47,7 +47,7 @@ class TestCaseMappingPreliminary < Test::Unit::TestCase
   # different properties; careful: roundtrip isn't always guaranteed
   def check_swapcase_properties(expected, start, *flags)
     assert_equal expected, start.swapcase(*flags)
-    temp = start
+    temp = +start
     assert_equal expected, temp.swapcase!(*flags)
     assert_equal start, start.swapcase(*flags).swapcase(*flags)
     assert_equal expected, expected.swapcase(*flags).swapcase(*flags)
@@ -61,10 +61,10 @@ class TestCaseMappingPreliminary < Test::Unit::TestCase
   end
 
   def test_invalid
-    assert_raise(ArgumentError, "Should not be possible to upcase invalid string.") { "\xEB".force_encoding('UTF-8').upcase }
-    assert_raise(ArgumentError, "Should not be possible to downcase invalid string.") { "\xEB".force_encoding('UTF-8').downcase }
-    assert_raise(ArgumentError, "Should not be possible to capitalize invalid string.") { "\xEB".force_encoding('UTF-8').capitalize }
-    assert_raise(ArgumentError, "Should not be possible to swapcase invalid string.") { "\xEB".force_encoding('UTF-8').swapcase }
+    assert_raise(ArgumentError, "Should not be possible to upcase invalid string.") { "\xEB".dup.force_encoding('UTF-8').upcase }
+    assert_raise(ArgumentError, "Should not be possible to downcase invalid string.") { "\xEB".dup.force_encoding('UTF-8').downcase }
+    assert_raise(ArgumentError, "Should not be possible to capitalize invalid string.") { "\xEB".dup.force_encoding('UTF-8').capitalize }
+    assert_raise(ArgumentError, "Should not be possible to swapcase invalid string.") { "\xEB".dup.force_encoding('UTF-8').swapcase }
   end
 
   def test_general
diff --git a/test/ruby/enc/test_case_options.rb b/test/ruby/enc/test_case_options.rb
index e9bf50fcfc..40a85ee970 100644
--- a/test/ruby/enc/test_case_options.rb
+++ b/test/ruby/enc/test_case_options.rb
@@ -19,7 +19,7 @@ class TestCaseOptions < Test::Unit::TestCase
 
   def assert_raise_both_types(*options)
     assert_raise_functional_operations 'a', *options
-    assert_raise_bang_operations 'a', *options
+    assert_raise_bang_operations +'a', *options
     assert_raise_functional_operations :a, *options
   end
 
@@ -51,7 +51,7 @@ class TestCaseOptions < Test::Unit::TestCase
 
   def assert_okay_both_types(*options)
     assert_okay_functional_operations 'a', *options
-    assert_okay_bang_operations 'a', *options
+    assert_okay_bang_operations +'a', *options
     assert_okay_functional_operations :a, *options
   end
 
@@ -69,10 +69,10 @@ class TestCaseOptions < Test::Unit::TestCase
     assert_raise(ArgumentError) { 'a'.upcase :fold }
     assert_raise(ArgumentError) { 'a'.capitalize :fold }
     assert_raise(ArgumentError) { 'a'.swapcase :fold }
-    assert_nothing_raised { 'a'.downcase! :fold }
-    assert_raise(ArgumentError) { 'a'.upcase! :fold }
-    assert_raise(ArgumentError) { 'a'.capitalize! :fold }
-    assert_raise(ArgumentError) { 'a'.swapcase! :fold }
+    assert_nothing_raised { 'a'.dup.downcase! :fold }
+    assert_raise(ArgumentError) { 'a'.dup.upcase! :fold }
+    assert_raise(ArgumentError) { 'a'.dup.capitalize! :fold }
+    assert_raise(ArgumentError) { 'a'.dup.swapcase! :fold }
     assert_nothing_raised { :a.downcase :fold }
     assert_raise(ArgumentError) { :a.upcase :fold }
     assert_raise(ArgumentError) { :a.capitalize :fold }