diff --git a/libc/test/UnitTest/RoundingModeUtils.cpp b/libc/test/UnitTest/RoundingModeUtils.cpp
--- a/libc/test/UnitTest/RoundingModeUtils.cpp
+++ b/libc/test/UnitTest/RoundingModeUtils.cpp
@@ -8,7 +8,7 @@
 
 #include "RoundingModeUtils.h"
 
-#include <fenv.h>
+#include "src/__support/FPUtil/FEnvImpl.h"
 
 namespace __llvm_libc {
 namespace fputil {
@@ -34,15 +34,15 @@
 }
 
 ForceRoundingMode::ForceRoundingMode(RoundingMode mode) {
-  old_rounding_mode = fegetround();
+  old_rounding_mode = fputil::get_round();
   rounding_mode = get_fe_rounding(mode);
   if (old_rounding_mode != rounding_mode)
-    fesetround(rounding_mode);
+    fputil::set_round(rounding_mode);
 }
 
 ForceRoundingMode::~ForceRoundingMode() {
   if (old_rounding_mode != rounding_mode)
-    fesetround(old_rounding_mode);
+    fputil::set_round(old_rounding_mode);
 }
 
 } // namespace testing
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
--- a/libc/test/src/CMakeLists.txt
+++ b/libc/test/src/CMakeLists.txt
@@ -1,7 +1,7 @@
 function(add_fp_unittest name)
   cmake_parse_arguments(
     "MATH_UNITTEST"
-    "NEED_MPFR" # Optional arguments
+    "NEED_MPFR;HERMETIC_TEST_ONLY" # Optional arguments
     "" # Single value arguments
     "LINK_LIBRARIES" # Multi-value arguments
     ${ARGN}
@@ -14,13 +14,21 @@
     endif()
   endif()
 
+  if(MATH_UNITTEST_HERMETIC_TEST_ONLY)
+    set(test_type HERMETIC_TEST_ONLY)
+  endif()
   if(MATH_UNITTEST_NEED_MPFR)
+    if(MATH_UNITTEST_HERMETIC_TEST_ONLY)
+      message(FATAL "Hermetic math test cannot require MPFR.")
+    endif()
+    set(test_type UNIT_TEST_ONLY)
     list(APPEND MATH_UNITTEST_LINK_LIBRARIES libcMPFRWrapper libc_math_test_utils -lmpfr -lgmp)
   endif()
   list(APPEND MATH_UNITTEST_LINK_LIBRARIES LibcFPTestHelpers)
 
   add_libc_unittest(
     ${name}
+    ${test_type}
     LINK_LIBRARIES "${MATH_UNITTEST_LINK_LIBRARIES}"
     "${MATH_UNITTEST_UNPARSED_ARGUMENTS}"
   )
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -1,9 +1,9 @@
-add_custom_target(libc_stdlib_unittests)
+add_custom_target(libc-stdlib-tests)
 
-add_libc_unittest(
+add_libc_test(
   atof_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     atof_test.cpp
   DEPENDS
@@ -20,10 +20,10 @@
     libc.src.__support.CPP.type_traits
 )
 
-add_libc_unittest(
+add_libc_test(
   atoi_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     atoi_test.cpp
   DEPENDS
@@ -31,10 +31,10 @@
     libc.src.stdlib.atoi
 )
 
-add_libc_unittest(
+add_libc_test(
   atol_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     atol_test.cpp
   DEPENDS
@@ -42,10 +42,10 @@
     libc.src.stdlib.atol
 )
 
-add_libc_unittest(
+add_libc_test(
   atoll_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     atoll_test.cpp
   DEPENDS
@@ -56,23 +56,25 @@
 add_fp_unittest(
   strtod_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtod_test.cpp
   DEPENDS
     libc.src.errno.errno
     libc.src.stdlib.strtod
+    libc.src.__support.FPUtil.fenv_impl
 )
 
 add_fp_unittest(
   strtof_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtof_test.cpp
   DEPENDS
     libc.src.errno.errno
     libc.src.stdlib.strtof
+    libc.src.__support.FPUtil.fenv_impl
 )
 
 add_header_library(
@@ -85,10 +87,10 @@
     libc.src.errno.errno
 )
 
-add_libc_unittest(
+add_libc_test(
   strtol_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtol_test.cpp
   DEPENDS
@@ -96,10 +98,10 @@
     .strtol_test_support
 )
 
-add_libc_unittest(
+add_libc_test(
   strtold_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtold_test.cpp
   DEPENDS
@@ -108,10 +110,10 @@
     libc.src.stdlib.strtold
 )
 
-add_libc_unittest(
+add_libc_test(
   strtoll_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtoll_test.cpp
   DEPENDS
@@ -119,10 +121,10 @@
     .strtol_test_support
 )
 
-add_libc_unittest(
+add_libc_test(
   strtoul_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtoul_test.cpp
   DEPENDS
@@ -130,10 +132,10 @@
     .strtol_test_support
 )
 
-add_libc_unittest(
+add_libc_test(
   strtoull_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     strtoull_test.cpp
   DEPENDS
@@ -141,40 +143,40 @@
     .strtol_test_support
 )
 
-add_libc_unittest(
+add_libc_test(
   abs_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     abs_test.cpp
   DEPENDS
     libc.src.stdlib.abs
 )
 
-add_libc_unittest(
+add_libc_test(
   labs_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     labs_test.cpp
   DEPENDS
     libc.src.stdlib.labs
 )
 
-add_libc_unittest(
+add_libc_test(
   llabs_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     llabs_test.cpp
   DEPENDS
     libc.src.stdlib.llabs
 )
 
-add_libc_unittest(
+add_libc_test(
   div_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     div_test.cpp
   HDRS
@@ -184,10 +186,10 @@
     libc.src.stdlib.div
 )
 
-add_libc_unittest(
+add_libc_test(
   ldiv_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     ldiv_test.cpp
   HDRS
@@ -197,10 +199,10 @@
     libc.src.stdlib.ldiv
 )
 
-add_libc_unittest(
+add_libc_test(
   lldiv_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     lldiv_test.cpp
   HDRS
@@ -210,10 +212,10 @@
     libc.src.stdlib.lldiv
 )
 
-add_libc_unittest(
+add_libc_test(
   bsearch_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     bsearch_test.cpp
   DEPENDS
@@ -221,10 +223,10 @@
     libc.src.stdlib.bsearch
 )
 
-add_libc_unittest(
+add_libc_test(
   qsort_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     qsort_test.cpp
   DEPENDS
@@ -232,10 +234,10 @@
     libc.src.stdlib.qsort
 )
 
-add_libc_unittest(
+add_libc_test(
   rand_test
   SUITE
-    libc_stdlib_unittests
+    libc-stdlib-tests
   SRCS
     rand_test.cpp
   DEPENDS
@@ -246,10 +248,12 @@
 
 if(LLVM_LIBC_FULL_BUILD)
 
-  add_libc_unittest(
+  add_libc_test(
     _Exit_test
+    # The EXPECT_EXITS test is only availible for unit tests.
+    UNIT_TEST_ONLY
     SUITE
-      libc_stdlib_unittests
+      libc-stdlib-tests
     SRCS
       _Exit_test.cpp
     DEPENDS
@@ -258,10 +262,12 @@
       libc.src.stdlib.exit
   )
 
-  add_libc_unittest(
+  add_libc_test(
     atexit_test
+    # The EXPECT_EXITS test is only availible for unit tests.
+    UNIT_TEST_ONLY
     SUITE
-      libc_stdlib_unittests
+      libc-stdlib-tests
     SRCS
       atexit_test.cpp
     DEPENDS
@@ -273,10 +279,12 @@
       libc.src.__support.CPP.utility
   )
 
-  add_libc_unittest(
+  add_libc_test(
     abort_test
+    # The EXPECT_DEATH test is only availible for unit tests.
+    UNIT_TEST_ONLY
     SUITE
-      libc_stdlib_unittests
+      libc-stdlib-tests
     SRCS
       abort_test.cpp
     DEPENDS