When creating a new scenario or editing an existing one, you can configure it to emulate a mobile device environment on a per-scenario basis.
Configuring When Creating a New Scenario
Click New Scenario on the scenario list screen.
Click the Window Size dropdown list, and select the device you want to test from the Device Emulation section.

* When a device is selected, the window size is automatically set to the viewport size corresponding to that device. Devices cannot be selected if the default browser is set to Firefox.
Click Start to begin recording.
Changing Settings for an Existing Scenario
Open the target scenario on the scenario list screen.
Click Edit (
) next to the scenario name.
Click the Window Size dropdown list, and select the device you want to test from the Device Emulation section.
Click Save to apply the changes.
* You can also edit directly by clicking Edit () on the corresponding row of the scenario list screen.
Application Priority for Device Emulation
Device emulation during test execution from the scenario screen or during recording is applied in the following order of priority:
When device emulation is specified in the Nexus application settings (Highest Priority)
The device emulation settings under Settings > Recording and Local Execution Settings in the sidebar will be applied with the highest priority.
When not specified in the Nexus application, but specified in the scenario
The device emulation configured for each scenario will be applied.
When not configured in both the Nexus application and the scenario
Device emulation will not be applied; only the window size specified in the scenario will take effect.
On the other hand, when executing a test plan, the device emulation configured in the test plan's execution environment takes precedence.
If device emulation is not configured in the test plan execution environment, the device emulation specified in the scenario will be applied, regardless of the Nexus application settings.