diff --git a/build/VStudio/testing/winfsp-tests.vcxproj b/build/VStudio/testing/winfsp-tests.vcxproj
index 4c5555b8..0aca06df 100644
--- a/build/VStudio/testing/winfsp-tests.vcxproj
+++ b/build/VStudio/testing/winfsp-tests.vcxproj
@@ -185,6 +185,7 @@
     <ClCompile Include="..\..\..\tst\winfsp-tests\dirctl-test.c" />
     <ClCompile Include="..\..\..\tst\winfsp-tests\eventlog-test.c" />
     <ClCompile Include="..\..\..\tst\winfsp-tests\flush-test.c" />
+    <ClCompile Include="..\..\..\tst\winfsp-tests\fuse-opt-test.c" />
     <ClCompile Include="..\..\..\tst\winfsp-tests\info-test.c" />
     <ClCompile Include="..\..\..\tst\winfsp-tests\lock-test.c" />
     <ClCompile Include="..\..\..\tst\winfsp-tests\memfs-test.c" />
diff --git a/build/VStudio/testing/winfsp-tests.vcxproj.filters b/build/VStudio/testing/winfsp-tests.vcxproj.filters
index b8248deb..54a96231 100644
--- a/build/VStudio/testing/winfsp-tests.vcxproj.filters
+++ b/build/VStudio/testing/winfsp-tests.vcxproj.filters
@@ -55,6 +55,9 @@
     <ClCompile Include="..\..\..\tst\winfsp-tests\eventlog-test.c">
       <Filter>Source</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\tst\winfsp-tests\fuse-opt-test.c">
+      <Filter>Source</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\..\ext\tlib\testsuite.h">
diff --git a/inc/fuse/fuse_opt.h b/inc/fuse/fuse_opt.h
index 7a34f706..cdde8fed 100644
--- a/inc/fuse/fuse_opt.h
+++ b/inc/fuse/fuse_opt.h
@@ -47,7 +47,7 @@ extern "C" {
 #define FSP_FUSE_MEMFN_V                malloc, free
 #endif
 
-#define FUSE_OPT_KEY(templ, key)        { templ, -1U, key }
+#define FUSE_OPT_KEY(templ, key)        { templ, -1, key }
 #define FUSE_OPT_END                    { NULL, 0, 0 }
 
 #define FUSE_OPT_KEY_OPT                -1
diff --git a/tst/winfsp-tests/fuse-opt-test.c b/tst/winfsp-tests/fuse-opt-test.c
new file mode 100644
index 00000000..98dc39bb
--- /dev/null
+++ b/tst/winfsp-tests/fuse-opt-test.c
@@ -0,0 +1,314 @@
+#include <fuse/fuse_opt.h>
+#include <tlib/testsuite.h>
+#include <stddef.h>
+#include <string.h>
+
+struct data
+{
+    int fortytwo;
+    int a, b, c, d, e, f, g, h;
+    int i, j, k, l, m, n, o, p;
+    char *q, *r, *s, *t;
+    int u, v;
+    char *w;
+    short x;
+    long y;
+    long long z;
+    int arg_discard, arg_keep;
+    int opt_discard, opt_keep;
+    int nonopt_discard, nonopt_keep;
+};
+
+static int fuse_opt_parse_test_proc(void *data0, const char *arg, int key,
+    struct fuse_args *outargs)
+{
+    struct data *data = data0;
+
+    switch (key)
+    {
+    default:
+        ASSERT(0);
+        return -1;
+    case FUSE_OPT_KEY_OPT:
+        if (0 == strcmp("--arg-discard", arg))
+        {
+            data->arg_discard++;
+            return 0;
+        }
+        if (0 == strcmp("--arg-keep", arg))
+        {
+            data->arg_keep++;
+            return 1;
+        }
+        if (0 == strcmp("opt-discard", arg))
+        {
+            data->opt_discard++;
+            return 0;
+        }
+        if (0 == strcmp("opt-keep", arg))
+        {
+            data->opt_keep++;
+            return 1;
+        }
+        ASSERT(0);
+        return -1;
+    case FUSE_OPT_KEY_NONOPT:
+        if (0 == strcmp("--discard", arg))
+        {
+            data->nonopt_discard++;
+            return 1;
+        }
+        if (0 == strcmp("--keep", arg))
+        {
+            data->nonopt_keep++;
+            return 0;
+        }
+        ASSERT(0);
+        return -1;
+    case 'a':
+        ASSERT(0);
+        return -1;
+    case 'b':
+        ASSERT(0 == strcmp("-b", arg));
+        data->b = 'B';
+        return 1;
+    case 'c':
+        ASSERT(0);
+        return -1;
+    case 'd':
+        ASSERT(0 == strcmp("--dlong", arg));
+        data->d = 'D';
+        return 1;
+    case 'e':
+        ASSERT(0);
+        return -1;
+    case 'f':
+        ASSERT(0 == strcmp("f", arg));
+        data->f = 'F';
+        return 1;
+    case 'g':
+        ASSERT(0);
+        return -1;
+    case 'h':
+        ASSERT(0 == strcmp("hlong", arg));
+        data->h = 'H';
+        return 1;
+    case 'i':
+        ASSERT(0);
+        return -1;
+    case 'j':
+        ASSERT(0 == strcmp("-j=74", arg));
+        data->j = 'J';
+        return 1;
+    case 'k':
+        ASSERT(0);
+        return -1;
+    case 'l':
+        ASSERT(0 == strcmp("--llong=76", arg));
+        data->l = 'L';
+        return 1;
+    case 'm':
+        ASSERT(0);
+        return -1;
+    case 'n':
+        ASSERT(0 == strcmp("n=78", arg));
+        data->n = 'N';
+        return 1;
+    case 'o':
+        ASSERT(0);
+        return -1;
+    case 'p':
+        ASSERT(0 == strcmp("plong=80", arg));
+        data->p = 'P';
+        return 1;
+    case 'q':
+        ASSERT(0);
+        return -1;
+    case 'r':
+        ASSERT(0);
+        return -1;
+    case 's':
+        ASSERT(0);
+        return -1;
+    case 't':
+        ASSERT(0);
+        return -1;
+    case 'u':
+        ASSERT(0);
+        return -1;
+    case 'v':
+        ASSERT(0 == strcmp("-v86", arg));
+        data->v = 'V';
+        return 1;
+    case 'w':
+        ASSERT(0);
+        return -1;
+    case 'x':
+        ASSERT(0);
+        return -1;
+    case 'y':
+        ASSERT(0);
+        return -1;
+    case 'z':
+        ASSERT(0);
+        return -1;
+    }
+}
+
+void fuse_opt_parse_test(void)
+{
+    static struct fuse_opt opts[] =
+    {
+        { "-a", offsetof(struct data, a), 'a' },
+        FUSE_OPT_KEY("-b", 'b'),
+        { "--clong", offsetof(struct data, c), 'c' },
+        FUSE_OPT_KEY("--dlong", 'd'),
+        { "e", offsetof(struct data, e), 'e' },
+        FUSE_OPT_KEY("f", 'f'),
+        { "glong", offsetof(struct data, g), 'g' },
+        FUSE_OPT_KEY("hlong", 'h'),
+
+        { "-i=", offsetof(struct data, i), 'i' },
+        FUSE_OPT_KEY("-j=", 'j'),
+        { "--klong=", offsetof(struct data, k), 'k' },
+        FUSE_OPT_KEY("--llong=", 'l'),
+        { "m=", offsetof(struct data, m), 'm' },
+        FUSE_OPT_KEY("n=", 'n'),
+        { "olong=", offsetof(struct data, o), 'o' },
+        FUSE_OPT_KEY("plong=", 'p'),
+
+        { "-q=%s", offsetof(struct data, q), 'q' },
+        { "--rlong=%s", offsetof(struct data, r), 'r' },
+        { "s=%s", offsetof(struct data, s), 's' },
+        { "tlong=%s", offsetof(struct data, t), 't' },
+
+        { "-u ", offsetof(struct data, u), 'u' },
+        FUSE_OPT_KEY("-v ", 'v'),
+
+        { "-w %s", offsetof(struct data, w), 'w' },
+
+        { "-x=%hi", offsetof(struct data, x), 'x' },
+        { "-y=%li", offsetof(struct data, y), 'y' },
+        { "-z=%lli", offsetof(struct data, z), 'z' },
+
+        FUSE_OPT_KEY("--discard", FUSE_OPT_KEY_DISCARD),
+        FUSE_OPT_KEY("--keep", FUSE_OPT_KEY_KEEP),
+
+        FUSE_OPT_END,
+    };
+    static char *argv[] =
+    {
+        "exec",
+        "-a",
+        "-b",
+        "--clong",
+        "--dlong",
+        "-o", "e,f",
+        "-oglong,hlong",
+        "-i=73",
+        "-j=74",
+        "--klong=75",
+        "--llong=76",
+        "-om=77",
+        "-o", "n=78,olong=79,plong=80",
+        "-q=QqQq",
+        "--rlong=RrRrRrRr",
+        "-os=SsSs",
+        "-otlong=TtTtTtTt",
+        "-u85",
+        "-v", "86",
+        "-wWwWw",
+        "-x=65537",
+        "-y=0x100000001",
+        "-z=0x100000001",
+        "--discard",
+        "--keep",
+        "--arg-discard",
+        "--arg-keep",
+        "-oopt-discard",
+        "-oopt-keep",
+        "--",
+        "--discard",
+        "--keep",
+        0
+    };
+    static char *outargv[] =
+    {
+        "exec",
+        "-o", "f,hlong,n=78,plong=80,opt-keep",
+        "-b",
+        "--dlong",
+        "-j=74",
+        "--llong=76",
+        "-v86",
+        "--keep",
+        "--arg-keep",
+        "--",
+        "--discard",
+        0
+    };
+    struct fuse_args args = FUSE_ARGS_INIT(0, 0);
+    struct data data;
+    int result;
+
+    args.argc = sizeof argv / sizeof argv[0] - 1;
+    args.argv = argv;
+
+    memset(&data, 0, sizeof data);
+    data.fortytwo = 42;
+    result = fuse_opt_parse(&args, &data, opts, fuse_opt_parse_test_proc);
+    ASSERT(0 == result);
+
+    ASSERT(42 == data.fortytwo);
+    ASSERT('a' == data.a);
+    ASSERT('B' == data.b);
+    ASSERT('c' == data.c);
+    ASSERT('D' == data.d);
+    ASSERT('e' == data.e);
+    ASSERT('F' == data.f);
+    ASSERT('g' == data.g);
+    ASSERT('H' == data.h);
+    ASSERT('i' == data.i);
+    ASSERT('J' == data.j);
+    ASSERT('k' == data.k);
+    ASSERT('L' == data.l);
+    ASSERT('m' == data.m);
+    ASSERT('N' == data.n);
+    ASSERT('o' == data.o);
+    ASSERT('P' == data.p);
+    ASSERT(0 == strcmp("QqQq", data.q));
+    ASSERT(0 == strcmp("RrRrRrRr", data.r));
+    ASSERT(0 == strcmp("SsSs", data.s));
+    ASSERT(0 == strcmp("TtTtTtTt", data.t));
+    ASSERT('u' == data.u);
+    ASSERT('V' == data.v);
+    ASSERT(0 == strcmp("WwWw", data.w));
+    ASSERT(1 == data.x);
+    ASSERT((long)0x100000001 == data.y);
+    ASSERT((long long)0x100000001 == data.z);
+    ASSERT(1 == data.arg_discard);
+    ASSERT(1 == data.arg_keep);
+    ASSERT(1 == data.opt_discard);
+    ASSERT(1 == data.opt_keep);
+    ASSERT(1 == data.nonopt_discard);
+    ASSERT(1 == data.nonopt_keep);
+
+    ASSERT(args.argc == sizeof outargv / sizeof outargv[0] - 1);
+    for (size_t i = 0; args.argc > i; i++)
+        ASSERT(0 == strcmp(args.argv[i], outargv[i]));
+    ASSERT(0 == args.argv[args.argc]);
+    ASSERT(args.allocated);
+
+    fuse_opt_free_args(&args);
+
+    free(data.q);
+    free(data.r);
+    free(data.s);
+    free(data.t);
+    free(data.w);
+}
+
+void fuse_opt_tests(void)
+{
+    TEST(fuse_opt_parse_test);
+}
diff --git a/tst/winfsp-tests/winfsp-tests.c b/tst/winfsp-tests/winfsp-tests.c
index 8fbe68a1..6967e1d6 100644
--- a/tst/winfsp-tests/winfsp-tests.c
+++ b/tst/winfsp-tests/winfsp-tests.c
@@ -6,6 +6,7 @@ int WinFspNetTests = 1;
 
 int main(int argc, char *argv[])
 {
+    TESTSUITE(fuse_opt_tests);
     TESTSUITE(eventlog_tests);
     TESTSUITE(path_tests);
     TESTSUITE(mount_tests);