Tests for ListCommands SSM API endpoint.

Test that ListCommands returns commands sent by SendCommand as well as
filters by CommandId and InstanceId. In addition update the SendCommand
test for optional parameters.

tests/test_ssm/test_ssm_boto3.py

@@ -4,6 +4,10 @@ import boto3
 import botocore.exceptions
 import sure   # noqa
 import datetime
+import uuid
+
+from botocore.exceptions import ClientError
+from nose.tools import assert_raises
 
 from moto import mock_ssm
 
@@ -497,3 +501,59 @@ def test_send_command():
     cmd['OutputS3KeyPrefix'].should.equal('pref')
 
     cmd['ExpiresAfter'].should.be.greater_than(before)
+
+    # test sending a command without any optional parameters
+    response = client.send_command(
+        DocumentName=ssm_document)
+
+    cmd = response['Command']
+
+    cmd['CommandId'].should_not.be(None)
+    cmd['DocumentName'].should.equal(ssm_document)
+
+
+@mock_ssm
+def test_list_commands():
+    client = boto3.client('ssm', region_name='us-east-1')
+
+    ssm_document = 'AWS-RunShellScript'
+    params = {'commands': ['#!/bin/bash\necho \'hello world\'']}
+
+    response = client.send_command(
+        InstanceIds=['i-123456'],
+        DocumentName=ssm_document,
+        Parameters=params,
+        OutputS3Region='us-east-2',
+        OutputS3BucketName='the-bucket',
+        OutputS3KeyPrefix='pref')
+
+    cmd = response['Command']
+    cmd_id = cmd['CommandId']
+
+    # get the command by id
+    response = client.list_commands(
+        CommandId=cmd_id)
+
+    cmds = response['Commands']
+    len(cmds).should.equal(1)
+    cmds[0]['CommandId'].should.equal(cmd_id)
+
+    # add another command with the same instance id to test listing by
+    # instance id
+    client.send_command(
+        InstanceIds=['i-123456'],
+        DocumentName=ssm_document)
+
+    response = client.list_commands(
+        InstanceId='i-123456')
+
+    cmds = response['Commands']
+    len(cmds).should.equal(2)
+
+    for cmd in cmds:
+        cmd['InstanceIds'].should.contain('i-123456')
+
+    # test the error case for an invalid command id
+    with assert_raises(ClientError):
+        response = client.list_commands(
+            CommandId=str(uuid.uuid4()))