Add support for SCRIPT FLUSH subcommand

This commit adds support for the SCRIPT FLUSH subcommand which flushes
all the loaded scripts from Redis. The subcommand takes no arguments and
returns OK after completing its work.

README.rst

@@ -310,7 +310,6 @@ scripting
 ---------
 
  * script debug
- * script flush
  * script kill
 
 

fakeredis/_server.py

@@ -2316,8 +2316,7 @@ def time(self):
         return [str(now_s).encode(), str(now_us).encode()]
 
     # Script commands
-    # TODO: script flush
-    # (script debug and script kill will probably not be supported)
+    # script debug and script kill will probably not be supported
 
     def _convert_redis_arg(self, lua_runtime, value):
         # Type checks are exact to avoid issues like bool being a subclass of int.
@@ -2477,6 +2476,11 @@ def script(self, subcmd, *args):
             return sha1
         elif casematch(subcmd, b'exists'):
             return [int(sha1 in self._server.script_cache) for sha1 in args]
+        elif casematch(subcmd, b'flush'):
+            if len(args) != 0:
+                raise SimpleError(BAD_SUBCOMMAND_MSG.format('SCRIPT'))
+            self._server.script_cache = {}
+            return OK
         else:
             raise SimpleError(BAD_SUBCOMMAND_MSG.format('SCRIPT'))
 

test/test_fakeredis.py

@@ -4506,6 +4506,26 @@ def test_script_exists(r):
     assert r.script_exists("a", sha1_one, "c", sha1_two, "e", "f") == [0, 1, 0, 1, 0, 0]
 
 
+@pytest.mark.parametrize("args", [("a",), tuple("abcdefghijklmn")])
+def test_script_flush_errors_with_args(r, args):
+    with pytest.raises(redis.ResponseError):
+        raw_command(r, "SCRIPT FLUSH %s" % " ".join(args))
+
+
+def test_script_flush(r):
+    # generate/load six unique scripts and store their sha1 hash values
+    sha1_values = [r.script_load("return '%s'" % char) for char in "abcdef"]
+
+    # assert the scripts all exist prior to flushing
+    assert r.script_exists(*sha1_values) == [1] * len(sha1_values)
+
+    # flush and assert OK response
+    assert r.script_flush() is True
+
+    # assert none of the scripts exists after flushing
+    assert r.script_exists(*sha1_values) == [0] * len(sha1_values)
+
+
 @fake_only
 def test_lua_log(r, caplog):
     logger = fakeredis._server.LOGGER