docs: add api test cases documentation

apps/api/README.md

@@ -34,7 +34,8 @@ Imagine having a central hub where you can create and send notifications seamles
 - [Production Setup](docs/production-setup.md)
 - [Usage Guide](docs/usage-guide.md)
 - [Add New Provider](docs/add-new-provider.md)
-- [Block Diagram](/docs/block-diagram.md)
+- [Block Diagram](docs/block-diagram.md)
+- [API Test Cases](docs/api-test-cases.md)
 
 ## Contributing
 

apps/api/docs/api-test-cases.md

@@ -0,0 +1,80 @@
+# API Test Cases Documentation
+
+This document provides instructions on how to run the API test cases using Postman and Newman.
+
+## Prerequisites
+
+Before running the test cases, make sure you have the following prerequisites installed:
+
+- [Postman](https://www.postman.com/downloads/)
+- [Node.js](https://nodejs.org/) (v20.x or higher)
+
+## Getting Started
+
+1. Clone the repository (if not already done):
+
+   ```bash
+   git clone [email protected]:OsmosysSoftware/osmo-notify.git
+   ```
+
+2. Install Newman globally (for using Newman):
+
+   ```bash
+   npm install -g newman
+
+   # Optional, for generating HTML reports
+   npm install -g newman-reporter-html
+   ```
+
+3. Import the Postman collection:
+
+   1. Open Postman.
+   2. Click on the `Import` button.
+   3. Select the `apps/api/osmo-notify.postman_collection.json` file.
+
+## Running Test Cases
+
+### Using Postman
+
+1. Open Postman.
+2. Select the imported collection and click on the `Run` button near the top right.
+
+   Alternatively, click the three dots beside the collection name and click `Run collection`
+
+3. Select the environment on top right.
+4. Click `Run osmo-notify` to execute the test cases.
+
+### Using Newman
+
+1.  Export the environment file from Postman.
+2.  Open a terminal and run one of the following commands:
+
+    1. For console output
+
+       ```bash
+       newman run osmo-notify.postman_collection.json -e osmo-notify.postman_environment.json
+       ```
+
+    2. For HTML report
+
+       ```bash
+       newman run osmo-notify.postman_collection.json -e osmo-notify.postman_environment.json -r html
+       ```
+
+    Specify the path to the collection and environment file as required.
+
+## Viewing Results
+
+Both Postman and Newman provide detailed reports after running the test cases. You can view:
+
+- **Run results (for Postman):** Check the results on the Run results page in Postman after testing is completed.
+
+  ![Postman run results](assets/postman-api-run-results.png)
+
+- **Console Output (for Newman):** Check the terminal/console for test execution details.
+
+  ![Newman CLI run results](assets/newman-cli-run-results.png)
+
+- **HTML Report (for Newman):** After running Newman with the `-r html` flag, an HTML report is generated. Open the `newman/` directory and find the HTML file.
+
+  ![Newman HTML report](assets/newman-html-report.png)