Introduction

Spring Test MongoUnit is a library that provides a custom spring TestExecutionListener that can be added to your test class. This library offers a @DatabaseSetup annotation that can be used on class and method level. Based on the values provided in @DatabaseSetup before each test execution the resources you provided will loaded inside of your MongoDb

Configuration

To have Spring process @DatabaseSetup annotation you must first configure your tests to use the DatabaseSetupTestExecutionListener class. To do this you need to use the Spring @TestExecutionListeners annotation.

Example typical JUnit 4 test:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
@TestExecutionListeners({ DatabaseSetupTestExecutionListener.class })

See the Spring JavaDocs for details of the standard listeners.

In order for this library to access the Mongo database it requires that you provide a MongoTemplate bean, if you use Spring Boot package spring-boot-starter-data-mongodb, it will be provided automatically.

Setup

The @DatabaseSetup annotation indicates how Mongo collections should be setup before test methods are run. The annotation can be applied to individual test methods or to a whole class. When applied at the class level the setup occurs before each method in the test. The annotation value references a file that contains the json structure that you you want to be loaded into the database. This json structure can include setup for N collections.

Example format of this file:

{
  "myFirstCollection": {
    "_id": "key", // No matter what's the key name that you annotated with @ID you always define it as "_id"
    "someKey" : "someValue"
  },
  "mySecondCollection": {
    "_id": "key",
    "someKey" : "someValue"
  }
}

`

Here is a typical setup annotation. In this case a file named sampleData.json is contained in the same package as the test class.

@DatabaseSetup("sampleData.json")

By default setup will perform a REMOVE_SAVE operation, this means that all data from the collections referenced in the json file will be removed before saving new objects.