Ensure and assert tests run with UTF-8 external encoding

Some tests fail if the external/locale/filesystem encoding is ISO-8859-1

Rather than debugging environmental issues, we can control them
per Ruby docs by running our CI specs via
`ruby -E UTF-8 -S $spec_command`.

See https://github.com/ruby/ruby/blob/ca24e581ba/encoding.c#L1674

Alternatively, we could control them via the environmental variables
LANG, LC_ALL, LC_CTYPE
in the .travis.yml or appveyor.yml with e.g.

env:
  - LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8

(which is the default on Travis)
( http://docs.travis-ci.com/user/ci-environment/#Environment-variables )
but I'm not sure how windows-compatible that is and it appears
more reliable to be explicit in the runner, so that running
script/run_build uses the correct encoding, and one doesn't
need to, for example, gem install wwtd && wwtd --local
to get the CI behavior

Also, see see
https://github.com/rubyspec/rubyspec/blob/91ce9f6549/core/encoding/find_spec.rb#L57

script/functions.sh

@@ -26,7 +26,7 @@ function run_specs_and_record_done {
   fi;
 
   echo "${PWD}/bin/rspec"
-  $rspec_bin spec --backtrace --format progress --profile --format progress --out $SPECS_HAVE_RUN_FILE
+  ruby -E UTF-8:UTF-8 -S $rspec_bin spec --backtrace --format progress --profile --format progress --out $SPECS_HAVE_RUN_FILE
 }
 
 function run_cukes {
@@ -50,7 +50,7 @@ function run_cukes {
       # and PATH for those that are using `rspec` or `rake`.
       RUBYOPT="-I${PWD}/../bundle -rbundler/setup" \
          PATH="${PWD}/bin:$PATH" \
-         bin/cucumber --strict
+         ruby -E UTF-8:UTF-8 -S bin/cucumber --strict
     fi
   fi
 }
@@ -59,7 +59,7 @@ function run_specs_one_by_one {
   echo "Running each spec file, one-by-one..."
 
   for file in `find spec -iname '*_spec.rb'`; do
-    bin/rspec $file -b --format progress
+    ruby -E UTF-8:UTF-8 -S bin/rspec $file -b --format progress
   done
 }
 
@@ -112,7 +112,7 @@ function check_documentation_coverage {
 }
 
 function check_style_and_lint {
-  echo "bin/rubucop lib"
+  echo "bin/rubocop lib"
   bin/rubocop lib
 }
 

spec/rspec/support/encoded_string_spec.rb

@@ -16,6 +16,40 @@ module RSpec::Support
 
     if String.method_defined?(:encoding)
 
+      # see https://github.com/rubyspec/rubyspec/blob/91ce9f6549/core/encoding/find_spec.rb#L57
+      describe 'Ensure tests are running with utf-8 encoding' do
+
+        it 'default_internal' do
+          if Encoding.default_external == Encoding.find('locale')
+            expected_encoding = ''
+          else
+            expected_encoding = utf8_encoding
+          end
+          expect(Encoding.default_internal.to_s).to eq(expected_encoding)
+        end
+
+        it 'default_external' do
+          expect(Encoding.default_external.to_s).to eq(utf8_encoding)
+        end
+
+        it 'locale' do
+          skip "Not sure how to determine locale (#{Encoding.find('locale')})"\
+            "from LC_ALL or on windows"
+        end
+
+        it 'filesystem' do
+          encoding = Encoding.find('filesystem').to_s
+          if OS.windows?
+            skip "Not sure how to tell filesystem encoding is #{encoding}"
+            expect(encoding).to eq(utf8_encoding)
+          end
+        end
+
+        it 'current script (file)' do
+          expect(__ENCODING__.to_s).to eq(utf8_encoding)
+        end
+      end
+
       describe '#pick_encoding' do
         if String.method_defined?(:encoding)
           it "picks a compatible encoding, falling back to default_external" do