Handle delete of empty list of keys (#998)

Author: haroldsultan

lib/redis.rb

@@ -555,6 +555,9 @@ def migrate(key, options)
   # @param [String, Array<String>] keys
   # @return [Integer] number of keys that were deleted
   def del(*keys)
+    keys.flatten!(1)
+    return 0 if keys.empty?
+
     synchronize do |client|
       client.call([:del] + keys)
     end

test/commands_on_value_types_test.rb

@@ -14,6 +14,8 @@ def test_del
 
     assert_equal ["bar", "baz", "foo"], r.keys("*").sort
 
+    assert_equal 0, r.del("")
+
     assert_equal 1, r.del("foo")
 
     assert_equal ["bar", "baz"], r.keys("*").sort
@@ -30,6 +32,8 @@ def test_del_with_array_argument
 
     assert_equal ["bar", "baz", "foo"], r.keys("*").sort
 
+    assert_equal 0, r.del([])
+
     assert_equal 1, r.del(["foo"])
 
     assert_equal ["bar", "baz"], r.keys("*").sort