diff --git a/Makefile b/Makefile
index b7d92df..9b99264 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,7 @@ test:
 	cd fimdlp/testcpp && ./test
 
 coverage:
+	if [ -d fimdlp/testcpp/build/CMakeFiles ]; then rm -fr fimdlp/testcpp/build/CMakeFiles/*  ; fi;
 	make test
 	cd fimdlp/testcpp && ./cover
 
diff --git a/fimdlp/CPPFImdlp.cpp b/fimdlp/CPPFImdlp.cpp
index 27621d3..4b415c6 100644
--- a/fimdlp/CPPFImdlp.cpp
+++ b/fimdlp/CPPFImdlp.cpp
@@ -41,12 +41,10 @@ namespace mdlp {
         X = X_;
         y = y_;
         if (X.size() != y.size()) {
-            cerr << "X and y must have the same size" << endl;
-            return *this;
+            throw invalid_argument("X and y must have the same size");
         }
-        if (X.size() == 0) {
-            cerr << "X and y must have at least one element" << endl;
-            return *this;
+        if (X.size() == 0 || y.size() == 0) {
+            throw invalid_argument("X and y must have at least one element");
         }
         this->indices = sortIndices(X_);
         this->xDiscretized = labels(X.size(), -1);
diff --git a/fimdlp/cppfimdlp.cpython-310-darwin.so b/fimdlp/cppfimdlp.cpython-310-darwin.so
index 285ee7f..60cc322 100755
Binary files a/fimdlp/cppfimdlp.cpython-310-darwin.so and b/fimdlp/cppfimdlp.cpython-310-darwin.so differ
diff --git a/fimdlp/testcpp/FImdlp_unittest.cc b/fimdlp/testcpp/FImdlp_unittest.cc
index ced121f..e16a47f 100644
--- a/fimdlp/testcpp/FImdlp_unittest.cc
+++ b/fimdlp/testcpp/FImdlp_unittest.cc
@@ -59,6 +59,18 @@ namespace mdlp {
         }
 
     };
+    TEST_F(TestFImdlp, FitErrorEmptyDataset)
+    {
+        X = samples();
+        y = labels();
+        EXPECT_THROW(fit(X, y), std::invalid_argument);
+    }
+    TEST_F(TestFImdlp, FitErrorDifferentSize)
+    {
+        X = { 1, 2, 3 };
+        y = { 1, 2 };
+        EXPECT_THROW(fit(X, y), std::invalid_argument);
+    }
     TEST_F(TestFImdlp, SortIndices)
     {
         X = { 5.7, 5.3, 5.2, 5.1, 5.0, 5.6, 5.1, 6.0, 5.1, 5.9 };