check that BFloat16 can hold all int8_t values without precision loss

1 files changed, 12 insertions, 0 deletions

diff --git a/vespalib/src/tests/util/bfloat16/bfloat16_test.cpp b/vespalib/src/tests/util/bfloat16/bfloat16_test.cpp
index 4e4129feb78..5d70c95b1d9 100644
--- a/vespalib/src/tests/util/bfloat16/bfloat16_test.cpp
+++ b/vespalib/src/tests/util/bfloat16/bfloat16_test.cpp
@@ -34,6 +34,18 @@ TEST(BFloat16Test, normal_usage) {
     EXPECT_EQ(float(b2), 0x110);
 }
 
+TEST(BFloat16Test, has_range_of_int_8) {
+    for (int i = -128; i < 128; ++i) {
+        int8_t byte = i;
+        float flt = byte;
+        EXPECT_EQ(byte, i);
+        EXPECT_EQ(flt, i);
+        BFloat16 value = flt;
+        float recover = value;
+        EXPECT_EQ(recover, flt);
+    }
+}
+
 TEST(BFloat16Test, with_nbostream) {
     nbostream buf;
     for (BFloat16 value : simple_values) {