How to install gtest

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According to the ros gtest wiki page (http://wiki.ros.org/gtest):

In ROS 1.0 (Box Turtle) and 1.2 (C Turtle), gtest is included as a ROS package. In later releases of ROS, it has been converted to a rosdep.

However, when I run the command:

$ rosdep install gtest

I get:

ERROR: Rosdep cannot find all required resources to answer your query
Missing resource gtest

The same thing happens if I run the command as root and with I all the variants I can think of (including g-test, googletest, and google-test). So how does one install gtest?