diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index f8a7ccd..a0e83fe 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -37,7 +37,7 @@
 #include "dlext_private.h"
 
 #define ASSERT_DL_NOTNULL(ptr) \
-    ASSERT_TRUE(ptr != nullptr) << "dlerror: " << dlerror()
+    ASSERT_TRUE((ptr) != nullptr) << "dlerror: " << dlerror()
 
 #define ASSERT_DL_ZERO(i) \
     ASSERT_EQ(0, i) << "dlerror: " << dlerror()
@@ -52,7 +52,7 @@
 typedef int (*fn)(void);
 #define LIBNAME "libdlext_test.so"
 #define LIBNAME_NORELRO "libdlext_test_norelro.so"
-#define LIBSIZE 1024*1024 // how much address space to reserve for it
+constexpr auto LIBSIZE = 1024 * 1024; // how much address space to reserve for it
 
 #if defined(__LP64__)
 #define NATIVE_TESTS_PATH "/nativetest64"
diff --git a/tests/string_test.cpp b/tests/string_test.cpp
index 2a9da10..763d65c 100644
--- a/tests/string_test.cpp
+++ b/tests/string_test.cpp
@@ -40,10 +40,10 @@
 #define STRLCAT_SUPPORTED
 #endif
 
-#define KB 1024
-#define SMALL 1*KB
-#define MEDIUM 4*KB
-#define LARGE 64*KB
+constexpr auto KB = 1024;
+constexpr auto SMALL = 1 * KB;
+constexpr auto MEDIUM = 4 * KB;
+constexpr auto LARGE = 64 * KB;
 
 static int signum(int i) {
   if (i < 0) {
diff --git a/tests/wchar_test.cpp b/tests/wchar_test.cpp
index e86d56d..000dc98 100644
--- a/tests/wchar_test.cpp
+++ b/tests/wchar_test.cpp
@@ -22,7 +22,7 @@
 #include <stdint.h>
 #include <wchar.h>
 
-#define NUM_WCHARS(num_bytes) (num_bytes/sizeof(wchar_t))
+#define NUM_WCHARS(num_bytes) ((num_bytes)/sizeof(wchar_t))
 
 TEST(wchar, sizeof_wchar_t) {
   EXPECT_EQ(4U, sizeof(wchar_t));