From aeb7974549fc4443be44fe62158996670a339e3b Mon Sep 17 00:00:00 2001
From: William Richard <wrichard@indigoag.com>
Date: Mon, 4 Nov 2019 12:49:09 -0500
Subject: [PATCH] Add get_parameter_history implementation and tests

---
 moto/ssm/models.py               |  5 ++-
 moto/ssm/responses.py            | 13 ++++++++
 tests/test_ssm/test_ssm_boto3.py | 54 ++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/moto/ssm/models.py b/moto/ssm/models.py
index 0f58a5ad5..e4f1727be 100644
--- a/moto/ssm/models.py
+++ b/moto/ssm/models.py
@@ -527,7 +527,10 @@ class SimpleSystemManagerBackend(BaseBackend):
 
         return result
 
-        return result
+    def get_parameter_history(self, name, with_decryption):
+        if name in self._parameters:
+            return self._parameters[name]
+        return None
 
     def _match_filters(self, parameter, filters=None):
         """Return True if the given parameter matches all the filters"""
diff --git a/moto/ssm/responses.py b/moto/ssm/responses.py
index 0bb034428..2711e5c6e 100644
--- a/moto/ssm/responses.py
+++ b/moto/ssm/responses.py
@@ -139,6 +139,19 @@ class SimpleSystemManagerResponse(BaseResponse):
         response = {"Version": result}
         return json.dumps(response)
 
+    def get_parameter_history(self):
+        name = self._get_param('Name')
+        with_decryption = self._get_param("WithDecryption")
+
+        result = self.ssm_backend.get_parameter_history(name, with_decryption)
+
+        response = {"Parameters": []}
+        for parameter_version in result:
+            param_data = parameter_version.describe_response_object(decrypt=with_decryption)
+            response['Parameters'].append(param_data)
+
+        return json.dumps(response)
+
     def add_tags_to_resource(self):
         resource_id = self._get_param("ResourceId")
         resource_type = self._get_param("ResourceType")
diff --git a/tests/test_ssm/test_ssm_boto3.py b/tests/test_ssm/test_ssm_boto3.py
index d50ceb528..0c8874c7b 100644
--- a/tests/test_ssm/test_ssm_boto3.py
+++ b/tests/test_ssm/test_ssm_boto3.py
@@ -813,6 +813,60 @@ def test_put_parameter_secure_custom_kms():
     response["Parameters"][0]["Value"].should.equal("value")
     response["Parameters"][0]["Type"].should.equal("SecureString")
 
+@mock_ssm
+def test_get_parameter_history():
+    client = boto3.client("ssm", region_name="us-east-1")
+
+    test_parameter_name = "test"
+
+    for i in range(3):
+        client.put_parameter(
+            Name=test_parameter_name, Description="A test parameter version %d" % i, Value="value-%d" % i, Type="String",
+            Overwrite=True
+        )
+
+    response = client.get_parameter_history(Name=test_parameter_name)
+    parameters_response = response['Parameters']
+
+    for index, param in enumerate(parameters_response):
+        param['Name'].should.equal(test_parameter_name)
+        param['Type'].should.equal('String')
+        param['Value'].should.equal('value-%d' % index)
+        param['Version'].should.equal(index + 1)
+        param['Description'].should.equal("A test parameter version %d" % index)
+
+    len(parameters_response).should.equal(3)
+
+@mock_ssm
+def test_get_parameter_history_with_secure_string():
+    client = boto3.client("ssm", region_name="us-east-1")
+
+    test_parameter_name = "test"
+
+    for i in range(3):
+        client.put_parameter(
+            Name=test_parameter_name, Description="A test parameter version %d" % i, Value="value-%d" % i, Type="SecureString",
+            Overwrite=True
+        )
+
+    for with_decryption in [True, False]:
+        response = client.get_parameter_history(Name=test_parameter_name, WithDecryption=with_decryption)
+        parameters_response = response['Parameters']
+
+        for index, param in enumerate(parameters_response):
+            param['Name'].should.equal(test_parameter_name)
+            param['Type'].should.equal('SecureString')
+            expected_plaintext_value = 'value-%d' % index
+            if with_decryption:
+                param['Value'].should.equal(expected_plaintext_value)
+            else:
+                param['Value'].should.equal('kms:alias/aws/ssm:%s' % expected_plaintext_value)
+            param['Version'].should.equal(index + 1)
+            param['Description'].should.equal("A test parameter version %d" % index)
+
+        len(parameters_response).should.equal(3)
+
+
 
 @mock_ssm
 def test_add_remove_list_tags_for_resource():