Allow multiple arguments for pfcount

It now supports both an array of keys and multiple arguments.
For distributed access, it will now also ensure that all keys
are on the same node.

The tests were changed to do correctly work both for both scenarios
(keys were extended to use tags, so they land on the same node)
Additionally, a test for this behaviour was added.

Closes #450.

Author: badboy

lib/redis.rb

@@ -2483,9 +2483,9 @@ def pfadd(key, member)
   #
   # @param [String] key
   # @return [Fixnum]
-  def pfcount(key)
+  def pfcount(*keys)
     synchronize do |client|
-      client.call([:pfcount, key])
+      client.call([:pfcount] + keys.flatten(1))
     end
   end
 

lib/redis/distributed.rb

@@ -792,8 +792,10 @@ def pfadd(key, member)
     end
 
     # Get the approximate cardinality of members added to HyperLogLog structure.
-    def pfcount(key)
-      node_for(key).pfcount(key)
+    def pfcount(*keys)
+      ensure_same_node(:pfcount, keys.flatten(1)) do |node|
+        node.pfcount(keys)
+      end
     end
 
     # Merge multiple HyperLogLog values into an unique value that will approximate the cardinality of the union of

test/distributed_commands_on_hyper_log_log_test.rb

@@ -19,4 +19,15 @@ def test_pfmerge
     end
   end
 
-end
+  def test_pfcount_multiple_keys_diff_nodes
+    target_version "2.8.9" do
+      assert_raise Redis::Distributed::CannotDistribute do
+        r.pfadd "foo", "s1"
+        r.pfadd "bar", "s2"
+
+        assert r.pfcount("res", "foo", "bar")
+      end
+    end
+  end
+
+end

test/lint/hyper_log_log.rb

@@ -33,16 +33,28 @@ def test_pfcount
 
     def test_variadic_pfcount
       target_version "2.8.9" do
-        assert_equal 0, r.pfcount(["foo", "bar"])
+        assert_equal 0, r.pfcount(["{1}foo", "{1}bar"])
 
-        assert_equal true, r.pfadd("foo", "s1")
-        assert_equal true, r.pfadd("bar", "s1")
-        assert_equal true, r.pfadd("bar", "s2")
+        assert_equal true, r.pfadd("{1}foo", "s1")
+        assert_equal true, r.pfadd("{1}bar", "s1")
+        assert_equal true, r.pfadd("{1}bar", "s2")
+
+        assert_equal 2, r.pfcount(["{1}foo", "{1}bar"])
+      end
+    end
+
+    def test_variadic_pfcount_expanded
+      target_version "2.8.9" do
+        assert_equal 0, r.pfcount("{1}foo", "{1}bar")
+
+        assert_equal true, r.pfadd("{1}foo", "s1")
+        assert_equal true, r.pfadd("{1}bar", "s1")
+        assert_equal true, r.pfadd("{1}bar", "s2")
 
-        assert_equal 2, r.pfcount(["foo", "bar"])
+        assert_equal 2, r.pfcount("{1}foo", "{1}bar")
       end
     end
 
   end
 
-end
+end