diff --git a/ffmpeg/_run.py b/ffmpeg/_run.py
index 070a763..8048abf 100644
--- a/ffmpeg/_run.py
+++ b/ffmpeg/_run.py
@@ -106,10 +106,10 @@ def get_args(node):
 def run(node, cmd='ffmpeg'):
     """Run ffmpeg on node graph."""
     if isinstance(cmd, basestring):
-        args = [cmd]
+        cmd = [cmd]
     elif type(cmd) != list:
-        args = list(cmd)
-    args += node.get_args()
+        cmd = list(cmd)
+    args = cmd + node.get_args()
     _subprocess.check_call(args)
 
 
diff --git a/ffmpeg/tests/test_ffmpeg.py b/ffmpeg/tests/test_ffmpeg.py
index 2a6fc58..e32c5c6 100644
--- a/ffmpeg/tests/test_ffmpeg.py
+++ b/ffmpeg/tests/test_ffmpeg.py
@@ -1,5 +1,6 @@
 import ffmpeg
 import os
+import pytest
 import subprocess
 
 
@@ -118,4 +119,21 @@ def test_get_args_complex_filter():
 
 
 def test_run():
-    ffmpeg.run(_get_complex_filter_example())
+    node = _get_complex_filter_example()
+    ffmpeg.run(node)
+
+
+def test_run_dummy_cmd():
+    node = _get_complex_filter_example()
+    ffmpeg.run(node, cmd='true')
+
+
+def test_run_dummy_cmd_list():
+    node = _get_complex_filter_example()
+    ffmpeg.run(node, cmd=['true', 'ignored'])
+
+
+def test_run_failing_cmd():
+    node = _get_complex_filter_example()
+    with pytest.raises(subprocess.CalledProcessError):
+        ffmpeg.run(node, cmd='false')