Modify SSM put_parameter() to raise ValidationException if value is empty string (#3806)

* Modify put_parameter() to raise ValidationError when value is empty string

* Simplify empty string check

Co-authored-by: Tom Noble <tom.noble@bjss.com>

moto/ssm/models.py

@@ -1284,6 +1284,11 @@ class SimpleSystemManagerBackend(BaseBackend):
     def put_parameter(
         self, name, description, value, type, allowed_pattern, keyid, overwrite, tags,
     ):
+        if not value:
+            raise ValidationException(
+                "1 validation error detected: Value '' at 'value' failed to satisfy"
+                " constraint: Member must have length greater than or equal to 1."
+            )
         if name.lower().lstrip("/").startswith("aws") or name.lower().lstrip(
             "/"
         ).startswith("ssm"):

tests/test_ssm/test_ssm_boto3.py

@@ -299,6 +299,22 @@ def test_put_parameter():
     )
 
 
+@mock_ssm
+def test_put_parameter_empty_string_value():
+    client = boto3.client("ssm", region_name="us-east-1")
+    with pytest.raises(ClientError) as e:
+        client.put_parameter(Name="test_name", Value="", Type="String")
+    ex = e.value
+    ex.operation_name.should.equal("PutParameter")
+    ex.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(400)
+    ex.response["Error"]["Code"].should.contain("ValidationException")
+    ex.response["Error"]["Message"].should.equal(
+        "1 validation error detected: "
+        "Value '' at 'value' failed to satisfy constraint: "
+        "Member must have length greater than or equal to 1."
+    )
+
+
 @mock_ssm
 def test_put_parameter_invalid_names():
     client = boto3.client("ssm", region_name="us-east-1")