Adds Rubocop rule for line break after guard clause

Adds a rubocop rule (with autocorrect) to ensure line break after guard clauses.

1 files changed, 160 insertions, 0 deletions

diff --git a/spec/rubocop/cop/line_break_after_guard_clauses_spec.rb b/spec/rubocop/cop/line_break_after_guard_clauses_spec.rb
new file mode 100644
index 00000000000..8899dc85384
--- /dev/null
+++ b/spec/rubocop/cop/line_break_after_guard_clauses_spec.rb
@@ -0,0 +1,160 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/line_break_after_guard_clauses'
+
+describe RuboCop::Cop::LineBreakAfterGuardClauses do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  shared_examples 'examples with guard clause' do |title|
+    %w[if unless].each do |conditional|
+      it "flags violation for #{title} #{conditional} without line breaks" do
+        source = <<~RUBY
+          #{title} #{conditional} condition
+          do_stuff
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses.size).to eq(1)
+        offense = cop.offenses.first
+
+        expect(offense.line).to eq(1)
+        expect(cop.highlights).to eq(["#{title} #{conditional} condition"])
+        expect(offense.message).to eq('Add a line break after guard clauses')
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} with line break" do
+        source = <<~RUBY
+          #{title} #{conditional} condition
+
+          do_stuff
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} on multiple lines without line break" do
+        source = <<~RUBY
+          #{conditional} condition
+            #{title}
+          end
+          do_stuff
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by end keyword" do
+        source = <<~RUBY
+          def test
+            #{title} #{conditional} condition
+          end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by elsif keyword" do
+        source = <<~RUBY
+          if model
+            #{title} #{conditional} condition
+          elsif
+            do_something
+          end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by else keyword" do
+        source = <<~RUBY
+          if model
+            #{title} #{conditional} condition
+          else
+            do_something
+          end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by when keyword" do
+        source = <<~RUBY
+          case model
+            when condition_a
+              #{title} #{conditional} condition
+            when condition_b
+              do_something
+            end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by rescue keyword" do
+        source = <<~RUBY
+          begin
+            #{title} #{conditional} condition
+          rescue StandardError
+            do_something
+          end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by ensure keyword" do
+        source = <<~RUBY
+          def foo
+            #{title} #{conditional} condition
+          ensure
+            do_something
+          end
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "doesn't flag violation for #{title} #{conditional} without line breaks when followed by another guard clause" do
+        source = <<~RUBY
+          #{title} #{conditional} condition
+          #{title} #{conditional} condition
+
+          do_stuff
+        RUBY
+        inspect_source(cop, source)
+
+        expect(cop.offenses).to be_empty
+      end
+
+      it "autocorrects #{title} #{conditional} guard clauses without line break" do
+        source = <<~RUBY
+          #{title} #{conditional} condition
+          do_stuff
+        RUBY
+        autocorrected = autocorrect_source(cop, source)
+
+        expected_source = <<~RUBY
+          #{title} #{conditional} condition
+
+          do_stuff
+        RUBY
+        expect(autocorrected).to eql(expected_source)
+      end
+    end
+  end
+
+  %w[return fail raise next break throw].each do |example|
+    it_behaves_like 'examples with guard clause', example
+  end
+end