How to test default case when using Junit Parameterized.class - junit4

Question

I have an old version API: Foo(). Now I extend the API to Foo(false), Foo(true) and Foo() should still work as before.
Right now I am using Parameterized.class to do Junit, and the parameter list is {null, false, true}. I want to write the testcase as:
#Test
public void fooTest() {
Foo(parameter);
}
But Foo(parameter) cannot test Foo(), so I have to write the test code as:
#Test
public void fooTest() {
if (parameter == null)
Foo();
else
Foo(parameter);
}
Is there any simple way to write the test case so that I do not need to check whether parameter is null or not? I ask this because the original test cases before I extend API are already there in many places (see below) and I do not want to change the test code too much. :
#Test
public void fooTest() {
Foo();
}

Answer 1

One way could be to put the Foo-Object (instead of the constructor arguments) into the parameters, i.e. {Foo(false), Foo(true),Foo()} instead of {null, false, true}
Yet review your example. Probably it is an abstraction of a real problem. If not:
assertions are missing, these should be contained in the parameters (otherwise you get the if-problem in the assertion phase).
testing with 3 parameter values is easier done with 3 simple (un-parameterized) unittests
And you could of course put your default constructor into a separate (un-parametereized) test class.
Which alternative is the best depends heavily on the real problem behind your abstraction.