Add conversion tests

test/data_type/test_fp4.cpp

@@ -5,6 +5,7 @@
 #include "ck/utility/data_type.hpp"
 #include "ck/utility/type_convert.hpp"
 
+using ck::f4_convert_rne;
 using ck::f4_t;
 using ck::type_convert;
 
@@ -17,3 +18,29 @@ TEST(FP8, NumericLimits)
     EXPECT_EQ(ck::NumericLimits<f4_t>::MinSubnorm(), f4_t{0x1});
     EXPECT_EQ(ck::NumericLimits<f4_t>::MaxSubnorm(), f4_t{0x1});
 }
+
+TEST(FP8, ConvertFP32Nearest)
+{
+    // fix the tolerance value
+    float abs_tol = 1e-6;
+    float max_fp4 = 6.0f;
+    // convert 0 float to fp4 and back, check if holds
+    ASSERT_NEAR(0.0f, type_convert<float>(f4_convert_rne(0.0f)), abs_tol);
+    // convert maximal f4_t to float and check if equal to 6.0
+    ASSERT_NEAR(max_fp4, type_convert<float>(f4_convert_rne(max_fp4)), abs_tol);
+    // convert maximal float to fp4 and back, check if clipped to 6.0
+    ASSERT_NEAR(
+        max_fp4, type_convert<float>(f4_convert_rne(std::numeric_limits<float>::max())), abs_tol);
+    // positive norm float value to fp4 and back, check if holds
+    float pos_float = 1.0f;
+    ASSERT_NEAR(pos_float, type_convert<float>(f4_convert_rne(pos_float)), abs_tol);
+    // negative norm float value to fp4 and back, check if holds
+    float neg_float = -1.5f;
+    ASSERT_NEAR(neg_float, type_convert<float>(f4_convert_rne(neg_float)), abs_tol);
+    // positive subnorm float value to fp4 and back, check if holds
+    pos_float = 0.5f;
+    ASSERT_NEAR(pos_float, type_convert<float>(f4_convert_rne(pos_float)), abs_tol);
+    // negative subnorm float value to fp4 and back, check if holds
+    neg_float = -0.5f;
+    ASSERT_NEAR(neg_float, type_convert<float>(f4_convert_rne(neg_float)), abs_tol);
+}