Tell me how to test these events and ComponentDidMount? I need to test the call to componentdidmount and each event in the body of the function...

componentDidMount() {
   window.addEventListener('message', this.handleMessage);
   window.addEventListener('beforeunload', this.handleBeforeUnload);
   window.addEventListener('blur', this.handleAppFocusOut);
   window.addEventListener('focus', this.handleAppFocusIn);
}

Functions that are called on event are described here.

Here is described a few functions:

handleMessage = e => {
  if (e.data && e.data.adminToClient) {
    this.props.processAdminMessage(e.data.adminToClient);
  }
};



handleBeforeUnload = () => {
  sessionStorage.setItem('lastVisit', new Date().getTime().toString());
};



handleAppFocusOut = () => {
    const { activeElement } = document;

    if (activeElement?.nodeName !== 'BODY') {
      this.setState({ lastFocusedField: activeElement });
    }
  };



handleAppFocusIn = () => {
    if (this.state.lastFocusedField) {
      try {
        const focusField = this.state.lastFocusedField;
        setTimeout(() => {
          if (document.activeElement?.nodeName === 'BODY') {
            focusField.focus();
          }
        });
      } catch (err) {
        // Ignore any errors
      }
    }
    this.setState({ lastFocusedField: null });
  };