Introduce LongIdentifiers lint

lib/pelusa/lint.rb

@@ -7,6 +7,7 @@
 require 'pelusa/lint/properties'
 require 'pelusa/lint/collection_wrappers'
 require 'pelusa/lint/short_identifiers'
+require 'pelusa/lint/long_identifiers'
 require 'pelusa/lint/case_statements'
 require 'pelusa/lint/many_arguments'
 require 'pelusa/lint/eval_usage'
@@ -26,6 +27,7 @@ def self.all
         Properties,
         CollectionWrappers,
         ShortIdentifiers,
+        LongIdentifiers,
         ManyArguments,
         EvalUsage
       ]

lib/pelusa/lint/long_identifiers.rb

@@ -0,0 +1,58 @@
+module Pelusa
+  module Lint
+    class LongIdentifiers
+      def initialize
+        @violations = Set.new
+      end
+
+      def check(klass)
+        initialize
+        iterate_lines!(klass)
+
+        return SuccessfulAnalysis.new(name) if @violations.empty?
+
+        FailedAnalysis.new(name, formatted_violations) do |violations|
+          "These names are too long: #{violations.join(', ')}"
+        end
+      end
+
+      private
+
+      def name
+        "Uses names of adequate length (less than #{limit})"
+      end
+
+      def limit
+        Pelusa.configuration['LongIdentifiers'].fetch('limit', 20)
+      end
+
+      def iterate_lines!(klass)
+        iterator = Iterator.new do |node|
+          if node.respond_to?(:name)
+            name = node.name.respond_to?(:name) ? node.name.name.to_s : node.name.to_s
+            if name =~ /[a-z]/ && name.length > limit
+              next if name =~ /^[A-Z]/ # Ignore constants
+              @violations << [name, node.line]
+            end
+          end
+        end
+        Array(klass).each(&iterator)
+      end
+
+      def formatted_violations
+        grouped_violations = @violations.inject({}) do |hash, (name, line)|
+          hash[name] ||= []
+          hash[name] << line
+          hash
+        end
+
+        violations = []
+
+        grouped_violations.each_pair do |name, lines|
+          violations << "#{name} (line #{lines.join(', ')})"
+        end
+        violations
+      end
+    end
+  end
+end

test/pelusa/lint/long_identifiers_test.rb

@@ -0,0 +1,41 @@
+require 'test_helper'
+
+module Pelusa
+  module Lint
+    describe LongIdentifiers do
+      before do
+        @lint = LongIdentifiers.new
+      end
+
+      describe '#check' do
+        describe 'when the class contains no long identifiers' do
+          it 'returns a SuccessAnalysis' do
+            klass = """
+            class Foo
+              def initialize
+                not_long_identifier = nil
+              end
+            end""".to_ast
+
+            analysis = @lint.check(klass)
+            analysis.successful?.must_equal true
+          end
+        end
+
+        describe 'when the class contains a long identifier' do
+          it 'returns a FailureAnalysis' do
+            klass = """
+            class Foo
+              def initialize
+                it_is_long_identifier = nil
+              end
+            end""".to_ast
+
+            analysis = @lint.check(klass)
+            analysis.failed?.must_equal true
+          end
+        end
+      end
+    end
+  end
+end