Use shared examples for these tests

Author: Kevin Paulisse

spec/octocatalog-diff/tests/catalog-diff/cli/options/environment_spec.rb

@@ -4,28 +4,6 @@
 
 describe OctocatalogDiff::CatalogDiff::Cli::Options do
   describe '#opt_environment' do
-    it 'should handle --environment' do
-      result = run_optparse(['--environment', 'fizzbuzz'])
-      expect(result[:from_environment]).to eq('fizzbuzz')
-      expect(result[:to_environment]).to eq('fizzbuzz')
-    end
-
-    it 'should handle --to-environment' do
-      result = run_optparse(['--to-environment', 'fizzbuzz'])
-      expect(result[:from_environment]).to be_nil
-      expect(result[:to_environment]).to eq('fizzbuzz')
-    end
-
-    it 'should handle --from-environment' do
-      result = run_optparse(['--from-environment', 'fizzbuzz'])
-      expect(result[:from_environment]).to eq('fizzbuzz')
-      expect(result[:to_environment]).to be_nil
-    end
-
-    it 'should handle --from-environment + --to-environment' do
-      result = run_optparse(['--from-environment', 'fizzbuzz', '--to-environment', 'production'])
-      expect(result[:from_environment]).to eq('fizzbuzz')
-      expect(result[:to_environment]).to eq('production')
-    end
+    include_examples 'global string option', 'environment', :environment
   end
 end