diff --git a/app/meson.build b/app/meson.build
index f1cfa579..cf619557 100644
--- a/app/meson.build
+++ b/app/meson.build
@@ -35,6 +35,7 @@ executable('scrcpy', src, dependencies: dependencies)
 
 tests = [
     ['test_control_event_queue', ['tests/test_control_event_queue.c', 'src/controlevent.c']],
+    ['test_strutil', ['tests/test_strutil.c', 'src/strutil.c']],
 ]
 
 src_dir = include_directories('src')
diff --git a/app/tests/test_strutil.c b/app/tests/test_strutil.c
new file mode 100644
index 00000000..6dbc2ff3
--- /dev/null
+++ b/app/tests/test_strutil.c
@@ -0,0 +1,139 @@
+#include <assert.h>
+#include <string.h>
+
+#include "strutil.h"
+
+static void test_xstrncpy_simple() {
+    char s[] = "xxxxxxxxxx";
+    size_t w = xstrncpy(s, "abcdef", sizeof(s));
+
+    // returns strlen of copied string
+    assert(w == 6);
+
+    // is nul-terminated
+    assert(s[6] == '\0');
+
+    // does not write useless bytes
+    assert(s[7] == 'x');
+
+    // copies the content as expected
+    assert(!strcmp("abcdef", s));
+}
+
+static void test_xstrncpy_just_fit() {
+    char s[] = "xxxxxx";
+    size_t w = xstrncpy(s, "abcdef", sizeof(s));
+
+    // returns strlen of copied string
+    assert(w == 6);
+
+    // is nul-terminated
+    assert(s[6] == '\0');
+
+    // copies the content as expected
+    assert(!strcmp("abcdef", s));
+}
+
+static void test_xstrncpy_truncated() {
+    char s[] = "xxx";
+    size_t w = xstrncpy(s, "abcdef", sizeof(s));
+
+    // returns 'n' (sizeof(s))
+    assert(w == 4);
+
+    // is nul-terminated
+    assert(s[3] == '\0');
+
+    // copies the content as expected
+    assert(!strncmp("abcdef", s, 3));
+}
+
+static void test_xstrjoin_simple() {
+    const char *const tokens[] = { "abc", "de", "fghi", NULL };
+    char s[] = "xxxxxxxxxxxxxx";
+    size_t w = xstrjoin(s, tokens, ' ', sizeof(s));
+
+    // returns strlen of concatenation
+    assert(w == 11);
+
+    // is nul-terminated
+    assert(s[11] == '\0');
+
+    // does not write useless bytes
+    assert(s[12] == 'x');
+
+    // copies the content as expected
+    assert(!strcmp("abc de fghi", s));
+}
+
+static void test_xstrjoin_just_fit() {
+    const char *const tokens[] = { "abc", "de", "fghi", NULL };
+    char s[] = "xxxxxxxxxxx";
+    size_t w = xstrjoin(s, tokens, ' ', sizeof(s));
+
+    // returns strlen of concatenation
+    assert(w == 11);
+
+    // is nul-terminated
+    assert(s[11] == '\0');
+
+    // copies the content as expected
+    assert(!strcmp("abc de fghi", s));
+}
+
+static void test_xstrjoin_truncated_in_token() {
+    const char *const tokens[] = { "abc", "de", "fghi", NULL };
+    char s[] = "xxxxx";
+    size_t w = xstrjoin(s, tokens, ' ', sizeof(s));
+
+    // returns 'n' (sizeof(s))
+    assert(w == 6);
+
+    // is nul-terminated
+    assert(s[5] == '\0');
+
+    // copies the content as expected
+    assert(!strcmp("abc d", s));
+}
+
+static void test_xstrjoin_truncated_before_sep() {
+    const char *const tokens[] = { "abc", "de", "fghi", NULL };
+    char s[] = "xxxxxx";
+    size_t w = xstrjoin(s, tokens, ' ', sizeof(s));
+
+    // returns 'n' (sizeof(s))
+    assert(w == 7);
+
+    // is nul-terminated
+    assert(s[6] == '\0');
+
+    // copies the content as expected
+    assert(!strcmp("abc de", s));
+}
+
+static void test_xstrjoin_truncated_after_sep() {
+    const char *const tokens[] = { "abc", "de", "fghi", NULL };
+    char s[] = "xxxxxxx";
+    size_t w = xstrjoin(s, tokens, ' ', sizeof(s));
+
+    // returns 'n' (sizeof(s))
+    assert(w == 8);
+
+    // is nul-terminated
+    assert(s[7] == '\0');
+
+    // copies the content as expected
+    assert(!strcmp("abc de ", s));
+}
+
+int main() {
+    test_xstrncpy_simple();
+    test_xstrncpy_just_fit();
+    test_xstrncpy_truncated();
+    test_xstrjoin_simple();
+    test_xstrjoin_just_fit();
+    test_xstrjoin_truncated_in_token();
+    test_xstrjoin_truncated_before_sep();
+    test_xstrjoin_truncated_after_sep();
+    return 0;
+}