https://github.com/znsio/specmatic-google-pubsub-sample
https://github.com/znsio/specmatic-google-pubsub-sample
Last synced: about 1 year ago
JSON representation
- Host: GitHub
- URL: https://github.com/znsio/specmatic-google-pubsub-sample
- Owner: znsio
- Created: 2024-02-16T11:36:48.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-02-24T05:38:18.000Z (over 1 year ago)
- Last Synced: 2025-02-24T06:33:38.687Z (over 1 year ago)
- Language: Kotlin
- Size: 580 KB
- Stars: 1
- Watchers: 8
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Specmatic Google PubSub Sample
* [Specmatic Website](https://specmatic.in)
* [Specmatic Documenation](https://specmatic.in/documentation.html)
This sample project demonstrates how we can run contract tests against a service which interacts with a Google PubSub instance.
## Pre-requisites
* Gradle
* JDK 17+
* Docker
## Run the tests
1. Start Docker Desktop.
2. Run the following command -
```shell
./gradlew clean test
```
## Application Architecture
The service under test is: **Order Service**.
It listens for messages on a Google PubSub topic called **'place-order'**.
For every message it receives, it sends a message on a Google PubSub topics: **process-order** and **notification**.
We also have an async api specification defined for the Order Service in the **order_service.yaml** file.
The **order_service.yaml** is defined as a 'test' contract in the [specmatic.json](https://specmatic.in/documentation/specmatic_json.html) file.
## Contract Tests
To run contract tests, Specmatic leverages the "named examples" defined in the async api specification of the Order Service.
**Note**: As of now, contract tests will be generated only if there are named examples defined in the async api specification.
Here's the structure of a contract test:
- Specmatic will use the named example defined for the **'place-order'** topic and publish a message on the **'place-order'** topic.
If the example message does not match the message schema of the the **'place-order'** topic, the test will fail.
- Specmatic will wait for the Order Service to process the message and publish a message on the **'process-order'** and **'notification'** topics.
- Specmatic will then assert that :
- Exactly one message each is received on the **process-order** and **'notification'** topics
- The message received on the **process-order** topic is the named example defined for the **'process-order'** topic.
The message received should match the message schema for the **process-order** topic
- The message received on the **notification** topic is the named example defined for the **notification** topic.
The message received should match the message schema for the **notification** topic
## Running the tests with the Google PubSub Emulator
This project is setup to use the Google PubSub emulator by default.
1. Ensure that the PUBSUB_EMULATOR_HOST env variable is set appropriately while running tests. For this, add the following line in build.gradle.
```groovy
test {
environment "PUBSUB_EMULATOR_HOST", "localhost:8085"
}
```
2. Make use of the ```PubSubEmulator``` utility class to start the Google PubSub emulator in the contract tests. Here's how to create the pubsub emulator by specifying your **project id** and a list of topics:
```kotlin
private val pubSubEmulator = PubSubEmulator(
projectId = PROJECT_ID,
topics = listOf(PLACE_ORDER_TOPIC, PROCESS_ORDER_TOPIC, NOTIFICATION_TOPIC),
)
```
3. Start the emulator in your ```@BeforeAll``` method
```kotlin
pubSubEmulator.start()
```
4. Stop the emulator in your ```@AfterAll``` method
```kotlin
pubSubEmulator.stop()
```
## Running the tests with a live Google PubSub project
You can also run your tests against a real/live Google PubSub project.
Here are the steps:
- Create the following three topics in your project:
- **place-order**
- **process-order**
- **notification**
- Update the following with your Google PubSub project id:
- **application.properties** (src/main/resources/)
```yaml
google.pubsub.projectId=pub-sub-demo-414308
```
- **ContractTest**
```kotlin
private const val projectId = "pub-sub-demo-414308"
```
- Remove the following line from the `test` section in **build.gradle**
```
environment "PUBSUB_EMULATOR_HOST", "localhost:8085"
```
- You would need to then set up some authentication mechanism using one of the options described [here](https://cloud.google.com/docs/authentication/provide-credentials-adc#how-to).
- **Service Account with Key**
If you are planning to use a service account key, add this line in **build.gradle** in the `test` section after `useJUnitPlatform()`:
```
environment "GOOGLE_APPLICATION_CREDENTIALS", ""
```
## Troubleshooting
- If the contract tests fail due to expected messages not being received on the subscribe topics, try increasing the wait timeout of specmatic's ```GooglePubSubMock```.
For example, to make the ```GooglePubSubMock``` wait for 15 seconds, we can provide the timeout as follows -
```kotlin
GooglePubSubMock.connectWithBroker(PROJECT_ID, messageWaitTimeoutInMilliseconds = 15000)
```