The "Political Typology Quiz" created by the Pew Research Center and the ideology test available at The Political Compass are good sources for finding out whether someone is liberal or conservative. Pew's test is based on American ideology. The Political Compass test has a more worldly range of political views.
The Pew Research test shows two views for a variety of issues and asks the test-taker to choose which view most closely describes their ideology. The results show which political grouping on the political spectrum their views most closely align.
The Political Compass test asks whether the test-taker agrees or disagrees with a variety of political views then plots the results on an XY axis. Views can be compared to some historical figures or to the candidates in recent elections in countries like the United States, Canada and Germany. The website also has political reading lists for whatever views most closely align with the results of the ideology test.