chore: add smoke tests for nanbf16 math function

Signed-off-by: Krishna Pandey <[email protected]>

Author: krishna2803

libc/test/src/math/smoke/CMakeLists.txt

@@ -3515,6 +3515,22 @@ add_fp_unittest(
   UNIT_TEST_ONLY
 )
 
+add_fp_unittest(
+  nanbf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    nanbf16_test.cpp
+  DEPENDS
+    libc.hdr.signal_macros
+    libc.src.math.nanbf16
+    libc.src.__support.FPUtil.bfloat16
+    libc.src.__support.FPUtil.fp_bits
+  # FIXME: The nan tests currently have death tests, which aren't supported for
+  # hermetic tests.
+  UNIT_TEST_ONLY
+)
+
 add_fp_unittest(
   nearbyint_test
   SUITE

libc/test/src/math/smoke/nanbf16_test.cpp

@@ -0,0 +1,55 @@
+//===-- Unittests for nanbf16 ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "hdr/signal_macros.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/math/nanbf16.h"
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+class LlvmLibcNanf16Test : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+public:
+  using StorageType = LIBC_NAMESPACE::fputil::FPBits<bfloat16>::StorageType;
+
+  void run_test(const char *input_str, StorageType bits) {
+    bfloat16 result = LIBC_NAMESPACE::nanbf16(input_str);
+    auto actual_fp = LIBC_NAMESPACE::fputil::FPBits<bfloat16>(result);
+    auto expected_fp = LIBC_NAMESPACE::fputil::FPBits<bfloat16>(bits);
+    EXPECT_EQ(actual_fp.uintval(), expected_fp.uintval());
+  }
+};
+
+TEST_F(LlvmLibcNanf16Test, NCharSeq) {
+  run_test("", 0x7fc0);
+
+  // 0x7fc0 + 0x1f (31) = 0x7cdf
+  run_test("31", 0x7fdf);
+
+  // 0x7fc0 + 0x15 = 0x7fd5
+  run_test("0x15", 0x7fd5);
+
+  run_test("1a", 0x7fc0);
+  run_test("1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM_",
+           0x7fc0);
+  run_test("10000000000000000000000000000", 0x7fc0);
+}
+
+TEST_F(LlvmLibcNanf16Test, RandomString) {
+  run_test(" 1234", 0x7fc0);
+  run_test("-1234", 0x7fc0);
+  run_test("asd&f", 0x7fc0);
+  run_test("123 ", 0x7fc0);
+}
+
+#if defined(LIBC_ADD_NULL_CHECKS)
+TEST_F(LlvmLibcNanf16Test, InvalidInput) {
+  EXPECT_DEATH([] { LIBC_NAMESPACE::nanbf16(nullptr); }, WITH_SIGNAL(-1));
+}
+#endif // LIBC_ADD_NULL_CHECKS