diff --git a/libc/test/src/ctype/isalnum_test.cpp b/libc/test/src/ctype/isalnum_test.cpp
index 18ddd2b14b8c8..cfc54e95e922d 100644
--- a/libc/test/src/ctype/isalnum_test.cpp
+++ b/libc/test/src/ctype/isalnum_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsAlNum, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::isalnum('a'), 0);
-  EXPECT_NE(LIBC_NAMESPACE::isalnum('B'), 0);
-  EXPECT_NE(LIBC_NAMESPACE::isalnum('3'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::isalnum(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalnum('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalnum('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalnum(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char ALNUM_ARRAY[] = {
@@ -38,6 +29,19 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsAlNum, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::isalnum('a'), 0);
+  EXPECT_NE(LIBC_NAMESPACE::isalnum('B'), 0);
+  EXPECT_NE(LIBC_NAMESPACE::isalnum('3'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::isalnum(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalnum('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalnum('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalnum(-1), 0);
+}
+
 TEST(LlvmLibcIsAlNum, DefaultLocale) {
   // Loops through all characters, verifying that numbers and letters
   // return non-zero integer and everything else returns a zero.
diff --git a/libc/test/src/ctype/isalpha_test.cpp b/libc/test/src/ctype/isalpha_test.cpp
index e54b580dbe264..1e439cf973e35 100644
--- a/libc/test/src/ctype/isalpha_test.cpp
+++ b/libc/test/src/ctype/isalpha_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsAlpha, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::isalpha('a'), 0);
-  EXPECT_NE(LIBC_NAMESPACE::isalpha('B'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::isalpha('3'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalpha(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalpha('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalpha('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isalpha(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char ALPHA_ARRAY[] = {
@@ -37,6 +28,19 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsAlpha, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::isalpha('a'), 0);
+  EXPECT_NE(LIBC_NAMESPACE::isalpha('B'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::isalpha('3'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalpha(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalpha('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalpha('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isalpha(-1), 0);
+}
+
 TEST(LlvmLibcIsAlpha, DefaultLocale) {
   // Loops through all characters, verifying that letters return a
   // non-zero integer and everything else returns zero.
diff --git a/libc/test/src/ctype/isdigit_test.cpp b/libc/test/src/ctype/isdigit_test.cpp
index adea55e59c74d..0ee132d7f8515 100644
--- a/libc/test/src/ctype/isdigit_test.cpp
+++ b/libc/test/src/ctype/isdigit_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsDigit, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::isdigit('3'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit('a'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit('B'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isdigit(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char DIGIT_ARRAY[] = {
@@ -34,6 +25,19 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsDigit, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::isdigit('3'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit('a'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit('B'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isdigit(-1), 0);
+}
+
 TEST(LlvmLibcIsDigit, DefaultLocale) {
   // Loops through all characters, verifying that numbers and letters
   // return non-zero integer and everything else returns a zero.
diff --git a/libc/test/src/ctype/islower_test.cpp b/libc/test/src/ctype/islower_test.cpp
index f9414bd8cbd09..f877171abb9a3 100644
--- a/libc/test/src/ctype/islower_test.cpp
+++ b/libc/test/src/ctype/islower_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsLower, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::islower('a'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::islower('B'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::islower('3'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::islower(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::islower('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::islower('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::islower(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char LOWER_ARRAY[] = {
@@ -35,6 +26,19 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsLower, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::islower('a'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::islower('B'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::islower('3'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::islower(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::islower('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::islower('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::islower(-1), 0);
+}
+
 TEST(LlvmLibcIsLower, DefaultLocale) {
   // Loops through all characters, verifying that numbers and letters
   // return non-zero integer and everything else returns a zero.
diff --git a/libc/test/src/ctype/isupper_test.cpp b/libc/test/src/ctype/isupper_test.cpp
index 94def1a9dcccd..151ed23f0ac99 100644
--- a/libc/test/src/ctype/isupper_test.cpp
+++ b/libc/test/src/ctype/isupper_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsUpper, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::isupper('B'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::isupper('a'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isupper('3'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isupper(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isupper('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isupper('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isupper(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char UPPER_ARRAY[] = {
@@ -35,6 +26,19 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsUpper, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::isupper('B'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::isupper('a'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isupper('3'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isupper(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isupper('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isupper('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isupper(-1), 0);
+}
+
 TEST(LlvmLibcIsUpper, DefaultLocale) {
   // Loops through all characters, verifying that numbers and letters
   // return non-zero integer and everything else returns a zero.
diff --git a/libc/test/src/ctype/isxdigit_test.cpp b/libc/test/src/ctype/isxdigit_test.cpp
index d7253d549907b..ec58f0da49223 100644
--- a/libc/test/src/ctype/isxdigit_test.cpp
+++ b/libc/test/src/ctype/isxdigit_test.cpp
@@ -11,17 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcIsXdigit, SimpleTest) {
-  EXPECT_NE(LIBC_NAMESPACE::isxdigit('a'), 0);
-  EXPECT_NE(LIBC_NAMESPACE::isxdigit('B'), 0);
-  EXPECT_NE(LIBC_NAMESPACE::isxdigit('3'), 0);
-
-  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('z'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isxdigit(' '), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('?'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('\0'), 0);
-  EXPECT_EQ(LIBC_NAMESPACE::isxdigit(-1), 0);
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 constexpr char XDIGIT_ARRAY[] = {
@@ -36,6 +26,20 @@ bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return false;
 }
 
+} // namespace
+
+TEST(LlvmLibcIsXdigit, SimpleTest) {
+  EXPECT_NE(LIBC_NAMESPACE::isxdigit('a'), 0);
+  EXPECT_NE(LIBC_NAMESPACE::isxdigit('B'), 0);
+  EXPECT_NE(LIBC_NAMESPACE::isxdigit('3'), 0);
+
+  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('z'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isxdigit(' '), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('?'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isxdigit('\0'), 0);
+  EXPECT_EQ(LIBC_NAMESPACE::isxdigit(-1), 0);
+}
+
 TEST(LlvmLibcIsXdigit, DefaultLocale) {
   // Loops through all characters, verifying that numbers and letters
   // return non-zero integer and everything else returns a zero.
diff --git a/libc/test/src/ctype/tolower_test.cpp b/libc/test/src/ctype/tolower_test.cpp
index 59432c43297b3..fbcc5b8ee0d9d 100644
--- a/libc/test/src/ctype/tolower_test.cpp
+++ b/libc/test/src/ctype/tolower_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcToLower, SimpleTest) {
-  EXPECT_EQ(LIBC_NAMESPACE::tolower('a'), int('a'));
-  EXPECT_EQ(LIBC_NAMESPACE::tolower('B'), int('b'));
-  EXPECT_EQ(LIBC_NAMESPACE::tolower('3'), int('3'));
-
-  EXPECT_EQ(LIBC_NAMESPACE::tolower(' '), int(' '));
-  EXPECT_EQ(LIBC_NAMESPACE::tolower('?'), int('?'));
-  EXPECT_EQ(LIBC_NAMESPACE::tolower('\0'), int('\0'));
-  EXPECT_EQ(LIBC_NAMESPACE::tolower(-1), int(-1));
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 // Invariant: UPPER_ARR and LOWER_ARR are both the complete alphabet in the same
@@ -45,6 +36,19 @@ int span_index(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return -1;
 }
 
+} // namespace
+
+TEST(LlvmLibcToLower, SimpleTest) {
+  EXPECT_EQ(LIBC_NAMESPACE::tolower('a'), int('a'));
+  EXPECT_EQ(LIBC_NAMESPACE::tolower('B'), int('b'));
+  EXPECT_EQ(LIBC_NAMESPACE::tolower('3'), int('3'));
+
+  EXPECT_EQ(LIBC_NAMESPACE::tolower(' '), int(' '));
+  EXPECT_EQ(LIBC_NAMESPACE::tolower('?'), int('?'));
+  EXPECT_EQ(LIBC_NAMESPACE::tolower('\0'), int('\0'));
+  EXPECT_EQ(LIBC_NAMESPACE::tolower(-1), int(-1));
+}
+
 TEST(LlvmLibcToLower, DefaultLocale) {
   for (int ch = -255; ch < 255; ++ch) {
     int char_index = span_index(ch, UPPER_ARR);
diff --git a/libc/test/src/ctype/toupper_test.cpp b/libc/test/src/ctype/toupper_test.cpp
index 045b00bbb4b93..409b3cd96ed1e 100644
--- a/libc/test/src/ctype/toupper_test.cpp
+++ b/libc/test/src/ctype/toupper_test.cpp
@@ -11,16 +11,7 @@
 
 #include "test/UnitTest/Test.h"
 
-TEST(LlvmLibcToUpper, SimpleTest) {
-  EXPECT_EQ(LIBC_NAMESPACE::toupper('a'), int('A'));
-  EXPECT_EQ(LIBC_NAMESPACE::toupper('B'), int('B'));
-  EXPECT_EQ(LIBC_NAMESPACE::toupper('3'), int('3'));
-
-  EXPECT_EQ(LIBC_NAMESPACE::toupper(' '), int(' '));
-  EXPECT_EQ(LIBC_NAMESPACE::toupper('?'), int('?'));
-  EXPECT_EQ(LIBC_NAMESPACE::toupper('\0'), int('\0'));
-  EXPECT_EQ(LIBC_NAMESPACE::toupper(-1), int(-1));
-}
+namespace {
 
 // TODO: Merge the ctype tests using this framework.
 // Invariant: UPPER_ARR and LOWER_ARR are both the complete alphabet in the same
@@ -45,6 +36,19 @@ int span_index(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
   return -1;
 }
 
+} // namespace
+
+TEST(LlvmLibcToUpper, SimpleTest) {
+  EXPECT_EQ(LIBC_NAMESPACE::toupper('a'), int('A'));
+  EXPECT_EQ(LIBC_NAMESPACE::toupper('B'), int('B'));
+  EXPECT_EQ(LIBC_NAMESPACE::toupper('3'), int('3'));
+
+  EXPECT_EQ(LIBC_NAMESPACE::toupper(' '), int(' '));
+  EXPECT_EQ(LIBC_NAMESPACE::toupper('?'), int('?'));
+  EXPECT_EQ(LIBC_NAMESPACE::toupper('\0'), int('\0'));
+  EXPECT_EQ(LIBC_NAMESPACE::toupper(-1), int(-1));
+}
+
 TEST(LlvmLibcToUpper, DefaultLocale) {
   for (int ch = -255; ch < 255; ++ch) {
     int char_index = span_index(ch, LOWER_ARR);