With what you posted, it looks like your query only returns one row, the Test_Pressure is a parameter your feeding into the query. Are you trying to feed the result of the query back into the parameter? If you want to write back into the parameter you would have to do that through a script. I’m not sure with the example you gave why you would want to do that though. If you returned just one row of data, you can reference the value directly from the data returned from the query, in your report.
If you want to take the results of your one row returned and feed the Test_Pressure that was returned back into a parameter you can try something like:
rData = data['query'].getCoreResults()
data['Test_Pressure'] = rData.getValueAt(0,'Test_Pressure')
data['Test_Pressure'] = data['query'].getCoreResults().getValueAt(0,'Test_Pressure')