Isolator++ Professional supports faking template classes. The syntax uses the a.Fake.Instance API, just like when faking concrete classes.
Consider a simple template class:
template <class K>
class MyTemplateClass {
K a, b;
public:
MyTemplateClass(K _a, K _b) { a = _a; b = _b; }
K getSum() { return a + b; }
};
To change the behavior of the getSum method, you can use the following test:
TEST_F(TemplatesTests, MyTemplateClass_getSum_Return7)
{
// Arrange
auto a = Isolator();
auto fakeMyClass = a.Fake.Instance<MyTemplateClass<int>>();
a.CallTo(fake->getSum()).WillReturn(7);
// Act
int num = fake->getSum();
// Assert
ASSERT_EQ(num, 7);
}
Faking multiple type templates works the same way:
template <class T1, class T2>
class MyTemplateClass {
T1 t1;
T2 t2;
public:
MyTemplateClass(T1 _t1, T2 _t2) { t1 = _t1; t2 = _t2; }
T1 getSum() { return t1 + static_cast<T1>t2; }
};
TEST_F(TemplatesTests, MyTemplateClass_getSum_Return7)
{
// Arrange
auto a = Isolator();
auto fakeMyClass = a.Fake.Instance<MyTemplateClass<long,int>>();
a.CallTo(fake->getSum()).WillReturn(7);
// Act
int num = fake->getSum();
// Assert
ASSERT_EQ(num, 7);
}
Note: 
To fake multiple type templates on Linux you'll need to use a typedef.
typedef MyTemplateClass<long,int> MyTemplate_long_int; // Necessary only on Linux
auto fake = a.Fake.Instance<MyTemplate_long_int>();