Clarify that it's not necessary to subclass from TestCase to create a
test case. As Jeremy put it: "subclassing is an implementation
technique, not a type declaration".
diff --git a/Doc/lib/libunittest.tex b/Doc/lib/libunittest.tex
index e739a85..2bcda36 100644
--- a/Doc/lib/libunittest.tex
+++ b/Doc/lib/libunittest.tex
@@ -35,7 +35,8 @@
A \dfn{test case} is the smallest unit of testing. It checks for a
specific response to a particular set of inputs. PyUnit provides a
base class, \class{TestCase}, which may be used to create new test
-cases.
+cases. You may provide your own implementation that does not subclass
+from \class{TestCase}, of course.
\term{test suite}
A \dfn{test suite} is a collection of test cases, test suites, or