hrandfield (#1513)

* hrandfield

* use mapping in hset

* skip if version not fit

* remove empty line

* flake8 comments

* new line for each comment

Author: AvitalFineRedis

redis/client.py

@@ -1879,6 +1879,26 @@ def pttl(self, name):
         "Returns the number of milliseconds until the key ``name`` will expire"
         return self.execute_command('PTTL', name)
 
+    def hrandfield(self, key, count=None, withvalues=False):
+        """
+        Return a random field from the hash value stored at key.
+
+        count: if the argument is positive, return an array of distinct fields.
+        If called with a negative count, the behavior changes and the command
+        is allowed to return the same field multiple times. In this case,
+        the number of returned fields is the absolute value of the
+        specified count.
+        withvalues: The optional WITHVALUES modifier changes the reply so it
+        includes the respective values of the randomly selected hash fields.
+        """
+        params = []
+        if count is not None:
+            params.append(count)
+        if withvalues:
+            params.append("WITHVALUES")
+
+        return self.execute_command("HRANDFIELD", key, *params)
+
     def randomkey(self):
         "Returns the name of a random key"
         return self.execute_command('RANDOMKEY')

tests/test_commands.py

@@ -895,6 +895,19 @@ def test_pttl_no_key(self, r):
         "PTTL on servers 2.8 and after return -2 when the key doesn't exist"
         assert r.pttl('a') == -2
 
+    @skip_if_server_version_lt('6.2.0')
+    def test_hrandfield(self, r):
+        assert r.hrandfield('key') is None
+        r.hset('key', mapping={'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5})
+        assert r.hrandfield('key') is not None
+        assert len(r.hrandfield('key', 2)) == 2
+        # with values
+        assert len(r.hrandfield('key', 2, True)) == 4
+        # without duplications
+        assert len(r.hrandfield('key', 10)) == 5
+        # with duplications
+        assert len(r.hrandfield('key', -10)) == 10
+
     def test_randomkey(self, r):
         assert r.randomkey() is None
         for key in ('a', 'b', 'c'):