Formalize some patterns in cli specs (#28255)

spec/lib/mastodon/cli/feeds_spec.rb

@@ -4,20 +4,25 @@ require 'rails_helper'
 require 'mastodon/cli/feeds'
 
 describe Mastodon::CLI::Feeds do
+  subject { cli.invoke(action, arguments, options) }
+
   let(:cli) { described_class.new }
+  let(:arguments) { [] }
+  let(:options) { {} }
 
   it_behaves_like 'CLI Command'
 
   describe '#build' do
+    let(:action) { :build }
+
     before { Fabricate(:account) }
 
     context 'with --all option' do
       let(:options) { { all: true } }
 
       it 'regenerates feeds for all accounts' do
-        expect { cli.invoke(:build, [], options) }.to output(
-          a_string_including('Regenerated feeds')
-        ).to_stdout
+        expect { subject }
+          .to output_results('Regenerated feeds')
       end
     end
 
@@ -27,9 +32,8 @@ describe Mastodon::CLI::Feeds do
       let(:arguments) { ['alice'] }
 
       it 'regenerates feeds for the account' do
-        expect { cli.invoke(:build, arguments) }.to output(
-          a_string_including('OK')
-        ).to_stdout
+        expect { subject }
+          .to output_results('OK')
       end
     end
 
@@ -37,22 +41,23 @@ describe Mastodon::CLI::Feeds do
       let(:arguments) { ['invalid-username'] }
 
       it 'displays an error and exits' do
-        expect { cli.invoke(:build, arguments) }.to output(
-          a_string_including('No such account')
-        ).to_stdout.and raise_error(SystemExit)
+        expect { subject }
+          .to output_results('No such account')
+          .and raise_error(SystemExit)
       end
     end
   end
 
   describe '#clear' do
+    let(:action) { :clear }
+
     before do
       allow(redis).to receive(:del).with(key_namespace)
     end
 
     it 'clears the redis `feed:*` namespace' do
-      expect { cli.invoke(:clear) }.to output(
-        a_string_including('OK')
-      ).to_stdout
+      expect { subject }
+        .to output_results('OK')
 
       expect(redis).to have_received(:del).with(key_namespace).once
     end