[Fix rubocop#451] Make Rails/RelativeDateConstant aware of `yesterd…

…ay` and `tomorrow` methods.

CHANGELOG.md

@@ -21,6 +21,7 @@
 * [#440](https://github.com/rubocop/rubocop-rails/issues/440): This PR makes `Rails/TimeZone` aware of timezone specifier. ([@koic][])
 * [#381](https://github.com/rubocop/rubocop-rails/pull/381): Update `IgnoredMethods` list for `Lint/NumberConversion` to allow Rails' duration methods. ([@dvandersluis][])
 * [#444](https://github.com/rubocop/rubocop-rails/issues/444): Mark `Rails/Blank` as unsafe auto-correction. ([@koic][])
+* [#451](https://github.com/rubocop/rubocop-rails/issues/451): Make `Rails/RelativeDateConstant` aware of `yesterday` and `tomorrow` methods. ([@koic][])
 
 ## 2.9.1 (2020-12-16)
 

lib/rubocop/cop/rails/relative_date_constant.rb

@@ -33,7 +33,7 @@ class RelativeDateConstant < Base
 
         MSG = 'Do not assign %<method_name>s to constants as it ' \
               'will be evaluated only once.'
-        RELATIVE_METHODS = %i[since from_now after ago until before].freeze
+        RELATIVE_METHODS = %i[since from_now after ago until before yesterday tomorrow].freeze
 
         def on_casgn(node)
           return if node.children[2]&.block_type?

spec/rubocop/cop/rails/relative_date_constant_spec.rb

@@ -43,6 +43,40 @@ def self.expired_at
       RUBY
     end
 
+    it 'registers and corrects an offense when using `Date.yesterday`' do
+      expect_offense(<<~RUBY)
+        class SomeClass
+          RECENT_DATE = Date.yesterday
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not assign yesterday to constants as it will be evaluated only once.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        class SomeClass
+          def self.recent_date
+            Date.yesterday
+          end
+        end
+      RUBY
+    end
+
+    it 'registers and corrects an offense when using `Time.zone.tomorrow`' do
+      expect_offense(<<~RUBY)
+        class SomeClass
+          FUTURE_DATE = Time.zone.tomorrow
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not assign tomorrow to constants as it will be evaluated only once.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        class SomeClass
+          def self.future_date
+            Time.zone.tomorrow
+          end
+        end
+      RUBY
+    end
+
     it 'registers and corrects an offense when a method is chained after a relative method' do
       expect_offense(<<~RUBY)
         class SomeClass