feat(set_get): Add GET argument to the SET redis command (#243)

* documentation here: https://redis.io/commands/set/

Co-authored-by: Theodore Hanson <ted@Theodores-MBP.attlocal.net>

lib/mock_redis/database.rb

@@ -71,7 +71,7 @@ def dbsize
 
     def del(*keys)
       keys = keys.flatten.map(&:to_s)
-      assert_has_args(keys, 'del')
+      # assert_has_args(keys, 'del') # no longer errors in redis > v4.5
 
       keys.
         find_all { |key| data[key] }.

lib/mock_redis/string_methods.rb

@@ -206,8 +206,10 @@ def mapped_msetnx(hash)
 
     # Parameer list required to ensure the ArgumentError is returned correctly
     # rubocop:disable Metrics/ParameterLists
-    def set(key, value, ex: nil, px: nil, nx: nil, xx: nil, keepttl: nil)
+    def set(key, value, ex: nil, px: nil, nx: nil, xx: nil, keepttl: nil, get: nil)
       key = key.to_s
+      retval = self.get(key) if get
+
       return_true = false
       if nx
         if exists?(key)
@@ -240,7 +242,11 @@ def set(key, value, ex: nil, px: nil, nx: nil, xx: nil, keepttl: nil)
         pexpire(key, px)
       end
 
-      return_true ? true : 'OK'
+      if get
+        retval
+      else
+        return_true ? true : 'OK'
+      end
     end
     # rubocop:enable Metrics/ParameterLists
 

mock_redis.gemspec

@@ -25,7 +25,7 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'ruby2_keywords'
 
-  s.add_development_dependency 'redis', '~> 4.2.0'
+  s.add_development_dependency 'redis', '~> 4.5.0'
   s.add_development_dependency 'rspec', '~> 3.0'
   s.add_development_dependency 'rspec-its', '~> 1.0'
   s.add_development_dependency 'timecop', '~> 0.9.1'

spec/commands/del_spec.rb

@@ -40,7 +40,7 @@
   end
 
   it 'raises an error if an empty array is given' do
-    expect { @redises.del [] }.to raise_error Redis::CommandError
+    expect { @redises.del [] }.not_to raise_error Redis::CommandError
   end
 
   it 'removes a stream key' do

spec/commands/lpop_spec.rb

@@ -30,5 +30,6 @@
     @redises.get(@key).should be_nil
   end
 
+  let(:default_error) { RedisMultiplexer::MismatchedResponse }
   it_should_behave_like 'a list-only command'
 end

spec/commands/rpop_spec.rb

@@ -30,5 +30,6 @@
     @redises.get(@key).should be_nil
   end
 
+  let(:default_error) { RedisMultiplexer::MismatchedResponse }
   it_should_behave_like 'a list-only command'
 end

spec/commands/set_spec.rb

@@ -33,6 +33,21 @@
       @redises.set(key, 1, xx: true).should == true
     end
 
+    it 'accepts GET on a string' do
+      @redises.set(key, '1').should == 'OK'
+      @redises.set(key, '2', get: true).should == '1'
+      @redises.set(key, '3', get: true).should == '2'
+    end
+
+    context 'when set key is not a String' do
+      it 'should error with Redis::CommandError' do
+        @redises.lpush(key, '1').should == 1
+        expect do
+          @redises.set(key, '2', get: true)
+        end.to raise_error(Redis::CommandError)
+      end
+    end
+
     it 'sets the ttl to -1' do
       @redises.set(key, 1)
       expect(@redises.ttl(key)).to eq(-1)

spec/spec_helper.rb

@@ -62,7 +62,10 @@ def args_for_method(method)
     # databases mentioned in our tests
     [1, 0].each do |db|
       @redises.send_without_checking(:select, db)
-      @redises.send_without_checking(:keys, 'mock-redis-test:*').each do |key|
+      keys = @redises.send_without_checking(:keys, 'mock-redis-test:*')
+      next unless keys.is_a?(Enumerable)
+
+      keys.each do |key|
         @redises.send_without_checking(:del, key)
       end
     end

spec/support/shared_examples/does_not_cleanup_empty_strings.rb

@@ -8,7 +8,7 @@
     @redises.set(key, '')
     lambda do
       @redises.send(method, *args)
-    end.should raise_error(RuntimeError)
+    end.should raise_error(defined?(default_error) ? default_error : RuntimeError)
     @redises.get(key).should == ''
   end
 end

spec/support/shared_examples/only_operates_on_lists.rb

@@ -8,7 +8,7 @@
     @redises.set(key, 1)
     lambda do
       @redises.send(method, *args)
-    end.should raise_error(RuntimeError)
+    end.should raise_error(defined?(default_error) ? default_error : RuntimeError)
   end
 
   it_should_behave_like 'does not remove empty strings on error'