diff --git a/src/tests/system/libroot/posix/Jamfile b/src/tests/system/libroot/posix/Jamfile
index 0c8da1c546..05171df207 100644
--- a/src/tests/system/libroot/posix/Jamfile
+++ b/src/tests/system/libroot/posix/Jamfile
@@ -72,6 +72,10 @@ SimpleTest mbtest
 	: mbtest.c
 ;
 
+SimpleTest testmb
+	: testmb.c
+;
+
 SimpleTest tst-btowc
 	: tst-btowc.c
 ;
diff --git a/src/tests/system/libroot/posix/testmb.c b/src/tests/system/libroot/posix/testmb.c
new file mode 100644
index 0000000000..297373b945
--- /dev/null
+++ b/src/tests/system/libroot/posix/testmb.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+
+int
+main(int argc, char *argv[])
+{
+	wchar_t w[10];
+	char c[10];
+	int i;
+	int lose = 0;
+
+	i = mbstowcs(w, "bar", 4);
+	if (!(i == 3 && w[1] == 'a')) {
+		puts("mbstowcs FAILED!");
+		lose = 1;
+	}
+
+	mbstowcs(w, "blah", 5);
+	i = wcstombs(c, w, 10);
+	if (i != 4) {
+		puts("wcstombs FAILED!");
+		lose = 1;
+	}
+
+	if (mblen("foobar", 7) != 1) {
+		puts("mblen 1 FAILED!");
+		lose = 1;
+	}
+
+	if (mblen("", 1) != 0) {
+		puts("mblen 2 FAILED!");
+		lose = 1;
+	}
+
+	{
+		int r;
+		char c = 'x';
+		wchar_t wc;
+		char mbc[MB_CUR_MAX];
+
+		if ((r = mbtowc(&wc, &c, MB_CUR_MAX)) <= 0) {
+			printf("conversion to wide failed, result: %d\n", r);
+			lose = 1;
+		} else {
+			printf("wide value: 0x%04lx\n", (unsigned long) wc);
+			mbc[0] = '\0';
+			if ((r = wctomb(mbc, wc)) <= 0) {
+				printf("conversion to multibyte failed, result: %d\n", r);
+				lose = 1;
+			}
+		}
+
+	}
+
+	puts(lose ? "Test FAILED!" : "Test succeeded.");
+	return lose;
+}