# Sending Test Data

Test Flux channels and inspect how events move through downstream actions.

Using a channel’s **Test** feature, you can verify how data is processed by that channel and its downstream Flux app components.

1. Open the **Studio** tab of the Flux app.

2. Click the channel you want to test.

   For example:

   ![Screenshot highlighting the channel being opened for testing](https://docs.soracom.io/_astro/prepare-test-tab.CZQDTWBv_ZieXiq.webp)

3. Select the **Test** tab and enter your test data in the HTTP **Body** in JSON if applicable. If your test doesn't require any inputs, enter `{}` as an empty payload.

   ![Screenshot of the Test tab in the channel configuration](https://docs.soracom.io/_astro/channel-test-tab.CJ4NXN6z_21jDeU.webp)

4. If you want to override the context for the test, select the **Specify the context for message (context override)** checkbox and enter the context as JSON in **Context Override (JSON)**.

   This overrides the values of `context.*` and `event.context.*` that are referenced in **Action Condition** and other input fields. For the syntax, see [Use Expressions in Actions](https://docs.soracom.io/en/services/flux/action-expressions).

   By providing values in the same shape an event source would send, you can test-run the channel as if the message came from that event source. The following example imitates the Context of the IoT Device event source. For the Context each event source sends, see [IoT Device Event Source](https://docs.soracom.io/en/services/flux/iot-device).

   ```json
   {
     "eventType": "device"
   }
   ```

5. Click **Execute** to run the test and display results.

   You can also view the channel’s execution history, including tests run in the **Test** tab, in the **Messages** tab. For more information on viewing log history for Flux apps, channels, and actions, see [View Logs](https://docs.soracom.io/en/services/flux/logs).