PowerTester can connect to Power BI one of two ways, they are Master User OAuth Authentication or via an Service Principal.
Service principal Authentication
For Service principal authentication you must provide PowerTester with an Azure AD service principal object. This authentication method is the recommended authorisation method. The service principal requires read access to your Power BI tenant.
PowerTester requires your tenant Id, Service principal App Id & Service principal secret in order to connect to your power BI workspace.
View this Microsoft tutorial for how to create a service principal and retrieve those values: Create an Azure Active Directory application and service principal that can access resources.
Master user OAuth Authentication
For both logging into PowerTester and authenticating connections with Power BI, PowerTester uses the Microsoft identity platform in combination with OAuth 2.0.
OAuth 2.0, which stands for “Open Authorization”, is a standard designed to allow a website or application to access resources hosted by other web apps on behalf of a user. OAuth 2.0 is the industry protocol for authorization.
The OAuth 2.0 authorization code flow is described in section 4.1 of the OAuth 2.0 specification. PoweTester using the OAuth 2.0 authorization code flow acquire an access_token to include in requests to resources protected by the Microsoft identity platform (ie Power BI resources).
This enabled PowerTester to connect to your Power BI workspace, without storing any user credentials or passwords. PowerTester leverages the Microsoft identity platform to ensure the authentication is secure and follows industry current best practices.
Microsoft Fabric (Preview)
Currently Microsoft Fabric workspaces only allow Master User OAuth authentication. This is a technical limitation on Fabric workspaces. As Microsoft Fabric is in preview for Microsoft, we are hoping this issue is resolved by the time it goes GA.