Add test for TF1 constructors

hist/hist/inc/TF1.h

@@ -321,7 +321,7 @@ public:
    TF1(const char *name, std::function<T(const T *data, const Double_t *param)> &fcn, Double_t xmin = 0, Double_t xmax = 1, Int_t npar = 0, Int_t ndim = 1, EAddToList addToGlobList = EAddToList::kDefault):
       TF1(EFType::kTemplScalar, name, xmin, xmax, npar, ndim, addToGlobList, new TF1Parameters(npar), new TF1FunctorPointerImpl<T>(fcn))
    {
-      fType = std::is_same<T, double>::value? TF1::EFType::kTemplScalar : TF1::EFType::kTemplVec;
+      fType = std::is_same<T, double>::value ? TF1::EFType::kTemplScalar : TF1::EFType::kTemplVec;
    }
 
    ////////////////////////////////////////////////////////////////////////////////

hist/hist/test/test_tf1.cxx

@@ -8,6 +8,25 @@
 
 using namespace std;
 
+class MyClass {
+public:
+   double operator()(double *x, double *p) { return *x + *p; };
+};
+
+class MyClassConst {
+public:
+   double operator()(const double *x, const double *p) { return *x + *p; };
+};
+
+double func(const double *x, const double *p)
+{
+   return *x + *p;
+}
+double functionConst(const double *x, const double *p)
+{
+   return *x + *p;
+}
+
 Float_t delta = 0.00000000001;
 
 void coeffNamesGeneric(TString &formula, TObjArray *coeffNames)
@@ -177,3 +196,26 @@ TEST(TF1, CopyClone)
 {
    test_copyClone();
 }
+
+TEST(TF1, Constructors)
+{
+
+   MyClass testObj, testObjConst;
+   double x = 1;
+   double p = 1;
+
+   std::function<double(const double *data, const double *param)> stdFunction = functionConst;
+   std::vector<TF1> vtf1;
+   vtf1.emplace_back(TF1("Functor", testObj, 0, 1, 0));
+   vtf1.emplace_back(TF1("FunctorConst", testObjConst, 0, 1, 0));
+   vtf1.emplace_back(TF1("FunctorPtr", &testObj, 0, 1, 0));
+   vtf1.emplace_back(TF1("FunctorConstPtr", &testObjConst, 0, 1, 0));
+   vtf1.emplace_back(TF1("function", func));
+   vtf1.emplace_back(TF1("functionConst", functionConst));
+   vtf1.emplace_back(TF1("lambda", [](double *x1, double *x2) { return *x1 + *x2; }));
+   vtf1.emplace_back(TF1("lambdaConst", [](double *x1, double *x2) { return *x1 + *x2; }));
+   vtf1.emplace_back(TF1("stdFunction", stdFunction));
+
+   for (auto tf1 : vtf1)
+      EXPECT_EQ(tf1(&x, &p), 2);
+}