Add sub-minimal mocking of elasticbeanstalk:create_application()

moto/eb/models.py

@@ -0,0 +1,37 @@
+import boto.beanstalk
+
+from moto.core import BaseBackend, BaseModel
+from .exceptions import InvalidParameterValueError
+
+
+class FakeApplication(BaseModel):
+    def __init__(self, application_name):
+        self.application_name = application_name
+
+
+class EBBackend(BaseBackend):
+    def __init__(self, region):
+        self.region = region
+        self.applications = dict()
+
+    def reset(self):
+        # preserve region
+        region = self.region
+        self._reset_model_refs()
+        self.__dict__ = {}
+        self.__init__(region)
+
+    def create_application(self, application_name):
+        if application_name in self.applications:
+            raise InvalidParameterValueError(
+                "Application {} already exists.".format(application_name)
+            )
+        new_app = FakeApplication(
+            application_name=application_name,
+        )
+        self.applications[application_name] = new_app
+        return new_app
+
+
+eb_backends = dict((region.name, EBBackend(region.name))
+                   for region in boto.beanstalk.regions())