diff --git a/tests/Makefile b/tests/Makefile
index 7d2a7f9169..0f3489d4a8 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -46,7 +46,9 @@ EXPECT_NAMES=\
 	glob \
 	iso646 \
 	libgen \
-	locale \
+	locale/duplocale \
+	locale/newlocale \
+	locale/setlocale \
 	math \
 	regex \
 	select \
diff --git a/tests/expected/bins_dynamic/locale.stderr b/tests/expected/bins_dynamic/locale/duplocale.stderr
similarity index 100%
rename from tests/expected/bins_dynamic/locale.stderr
rename to tests/expected/bins_dynamic/locale/duplocale.stderr
diff --git a/tests/expected/bins_static/locale.stderr b/tests/expected/bins_dynamic/locale/duplocale.stdout
similarity index 100%
rename from tests/expected/bins_static/locale.stderr
rename to tests/expected/bins_dynamic/locale/duplocale.stdout
diff --git a/tests/expected/bins_dynamic/locale/newlocale.stderr b/tests/expected/bins_dynamic/locale/newlocale.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_dynamic/locale/newlocale.stdout b/tests/expected/bins_dynamic/locale/newlocale.stdout
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_dynamic/locale/setlocale.stderr b/tests/expected/bins_dynamic/locale/setlocale.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_dynamic/locale.stdout b/tests/expected/bins_dynamic/locale/setlocale.stdout
similarity index 100%
rename from tests/expected/bins_dynamic/locale.stdout
rename to tests/expected/bins_dynamic/locale/setlocale.stdout
diff --git a/tests/expected/bins_static/locale/duplocale.stderr b/tests/expected/bins_static/locale/duplocale.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_static/locale/duplocale.stdout b/tests/expected/bins_static/locale/duplocale.stdout
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_static/locale/newlocale.stderr b/tests/expected/bins_static/locale/newlocale.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_static/locale/newlocale.stdout b/tests/expected/bins_static/locale/newlocale.stdout
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_static/locale/setlocale.stderr b/tests/expected/bins_static/locale/setlocale.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/bins_static/locale.stdout b/tests/expected/bins_static/locale/setlocale.stdout
similarity index 100%
rename from tests/expected/bins_static/locale.stdout
rename to tests/expected/bins_static/locale/setlocale.stdout
diff --git a/tests/locale/duplocale.c b/tests/locale/duplocale.c
new file mode 100644
index 0000000000..735fbbe353
--- /dev/null
+++ b/tests/locale/duplocale.c
@@ -0,0 +1,39 @@
+#include <locale.h>
+#include <stdio.h>
+#include <assert.h>
+#include <stdint.h>
+
+int main() {
+    struct lconv *lconv0 = localeconv();
+
+    locale_t locale0 = uselocale(NULL);
+    assert(locale0 == LC_GLOBAL_LOCALE);
+
+    locale_t locale1 = uselocale(LC_GLOBAL_LOCALE);
+    assert(locale1 == LC_GLOBAL_LOCALE);
+
+    struct lconv *lconv1 = localeconv();
+    assert(lconv0 == lconv1);
+    
+    locale_t locale2 = newlocale(LC_ALL_MASK, "C", (locale_t)0);
+    assert(locale2 != LC_GLOBAL_LOCALE);
+
+    struct lconv *lconv2 = localeconv();
+    assert(lconv2 == lconv1);
+    
+    locale_t locale3 = duplocale(locale2);
+    assert(locale3 != locale2);
+    assert(locale3 != LC_GLOBAL_LOCALE);
+
+    locale_t locale4 = uselocale(locale3);
+    assert(locale4 == locale1);
+
+    struct lconv *lconv3 = localeconv();
+    assert(lconv3 != lconv2);
+
+    // should not crash
+    freelocale(locale3);
+    freelocale(locale2);
+    freelocale(locale1);
+    return 0;
+}
\ No newline at end of file
diff --git a/tests/locale/newlocale.c b/tests/locale/newlocale.c
new file mode 100644
index 0000000000..0dbb70b5f1
--- /dev/null
+++ b/tests/locale/newlocale.c
@@ -0,0 +1,16 @@
+#include <locale.h>
+#include <stdio.h>
+#include <assert.h>
+#include <stdint.h>
+
+int main() {    
+    locale_t locale0 = newlocale(LC_ALL_MASK, "C", (locale_t)0);
+    assert(locale0 != (locale_t)0);
+
+    locale_t locale1 = newlocale(LC_ALL_MASK, "non-existent-locale", (locale_t)0);
+    assert(locale1 == (locale_t)0);
+
+    // TODO: test with existing custom locale
+
+    return 0;
+}
diff --git a/tests/locale.c b/tests/locale/setlocale.c
similarity index 100%
rename from tests/locale.c
rename to tests/locale/setlocale.c