From 508b392697d4d166204a90aff51896031be5ba57 Mon Sep 17 00:00:00 2001
From: ramox- <adam@ramox.it>
Date: Wed, 21 Mar 2018 16:56:57 +0100
Subject: [PATCH] Make putparameter behave more like the real endpoint does,
 respond with Version or ParameterAlreadyExists (#1464)

---
 moto/ssm/models.py               |  1 +
 moto/ssm/responses.py            | 13 +++++++++++--
 tests/test_ssm/test_ssm_boto3.py | 23 ++++++++++++++++-------
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/moto/ssm/models.py b/moto/ssm/models.py
index 0f75599c3..af450e39e 100644
--- a/moto/ssm/models.py
+++ b/moto/ssm/models.py
@@ -126,6 +126,7 @@ class SimpleSystemManagerBackend(BaseBackend):
         last_modified_date = time.time()
         self._parameters[name] = Parameter(
             name, value, type, description, keyid, last_modified_date, version)
+        return version
 
     def add_tags_to_resource(self, resource_type, resource_id, tags):
         for key, value in tags.items():
diff --git a/moto/ssm/responses.py b/moto/ssm/responses.py
index 757bf0317..d9906a82e 100644
--- a/moto/ssm/responses.py
+++ b/moto/ssm/responses.py
@@ -162,9 +162,18 @@ class SimpleSystemManagerResponse(BaseResponse):
         keyid = self._get_param('KeyId')
         overwrite = self._get_param('Overwrite', False)
 
-        self.ssm_backend.put_parameter(
+        result = self.ssm_backend.put_parameter(
             name, description, value, type_, keyid, overwrite)
-        return json.dumps({})
+
+        if result is None:
+            error = {
+                '__type': 'ParameterAlreadyExists',
+                'message': 'Parameter {0} already exists.'.format(name)
+            }
+            return json.dumps(error), dict(status=400)
+
+        response = {'Version': result}
+        return json.dumps(response)
 
     def add_tags_to_resource(self):
         resource_id = self._get_param('ResourceId')
diff --git a/tests/test_ssm/test_ssm_boto3.py b/tests/test_ssm/test_ssm_boto3.py
index 0e8a770b3..97801e0b9 100644
--- a/tests/test_ssm/test_ssm_boto3.py
+++ b/tests/test_ssm/test_ssm_boto3.py
@@ -97,12 +97,14 @@ def test_get_parameters_by_path():
 def test_put_parameter():
     client = boto3.client('ssm', region_name='us-east-1')
 
-    client.put_parameter(
+    response = client.put_parameter(
         Name='test',
         Description='A test parameter',
         Value='value',
         Type='String')
 
+    response['Version'].should.equal(1)
+
     response = client.get_parameters(
         Names=[
             'test'
@@ -115,11 +117,16 @@ def test_put_parameter():
     response['Parameters'][0]['Type'].should.equal('String')
     response['Parameters'][0]['Version'].should.equal(1)
 
-    client.put_parameter(
-        Name='test',
-        Description='desc 2',
-        Value='value 2',
-        Type='String')
+    try:
+        client.put_parameter(
+            Name='test',
+            Description='desc 2',
+            Value='value 2',
+            Type='String')
+        raise RuntimeError('Should fail')
+    except botocore.exceptions.ClientError as err:
+        err.operation_name.should.equal('PutParameter')
+        err.response['Error']['Message'].should.equal('Parameter test already exists.')
 
     response = client.get_parameters(
         Names=[
@@ -134,13 +141,15 @@ def test_put_parameter():
     response['Parameters'][0]['Type'].should.equal('String')
     response['Parameters'][0]['Version'].should.equal(1)
 
-    client.put_parameter(
+    response = client.put_parameter(
         Name='test',
         Description='desc 3',
         Value='value 3',
         Type='String',
         Overwrite=True)
 
+    response['Version'].should.equal(2)
+
     response = client.get_parameters(
         Names=[
             'test'