diff --git a/tests/strings_test.cpp b/tests/strings_test.cpp
index 5200859..823aa4f 100644
--- a/tests/strings_test.cpp
+++ b/tests/strings_test.cpp
@@ -17,6 +17,7 @@
 #include <gtest/gtest.h>
 
 #include <errno.h>
+#include <locale.h>
 #include <strings.h>
 
 TEST(strings, ffs) {
@@ -30,3 +31,33 @@
   ASSERT_EQ(27, ffs(0x04000000));
   ASSERT_EQ(32, ffs(0x80000000));
 }
+
+TEST(strings, strcasecmp) {
+  ASSERT_EQ(0, strcasecmp("hello", "HELLO"));
+  ASSERT_LT(strcasecmp("hello1", "hello2"), 0);
+  ASSERT_GT(strcasecmp("hello2", "hello1"), 0);
+}
+
+TEST(strings, strcasecmp_l) {
+  locale_t l = newlocale(LC_ALL, "C", 0);
+  ASSERT_EQ(0, strcasecmp_l("hello", "HELLO", l));
+  ASSERT_LT(strcasecmp_l("hello1", "hello2", l), 0);
+  ASSERT_GT(strcasecmp_l("hello2", "hello1", l), 0);
+  freelocale(l);
+}
+
+TEST(strings, strncasecmp) {
+  ASSERT_EQ(0, strncasecmp("hello", "HELLO", 3));
+  ASSERT_EQ(0, strncasecmp("abcXX", "ABCYY", 3));
+  ASSERT_LT(strncasecmp("hello1", "hello2", 6), 0);
+  ASSERT_GT(strncasecmp("hello2", "hello1", 6), 0);
+}
+
+TEST(strings, strncasecmp_l) {
+  locale_t l = newlocale(LC_ALL, "C", 0);
+  ASSERT_EQ(0, strncasecmp_l("hello", "HELLO", 3, l));
+  ASSERT_EQ(0, strncasecmp_l("abcXX", "ABCYY", 3, l));
+  ASSERT_LT(strncasecmp_l("hello1", "hello2", 6, l), 0);
+  ASSERT_GT(strncasecmp_l("hello2", "hello1", 6, l), 0);
+  freelocale(l);
+}