Add unit test for float encoding

PR #3369 <https://github.com/Genymobile/scrcpy/pull/3369>

app/tests/test_binary.c

@@ -67,6 +67,17 @@ static void test_read64be(void) {
     assert(val == 0xABCD1234567890EF);
 }
 
+static void test_float_to_u16fp(void) {
+    assert(sc_float_to_u16fp(0.0f) == 0);
+    assert(sc_float_to_u16fp(0.03125f) == 0x800);
+    assert(sc_float_to_u16fp(0.0625f) == 0x1000);
+    assert(sc_float_to_u16fp(0.125f) == 0x2000);
+    assert(sc_float_to_u16fp(0.25f) == 0x4000);
+    assert(sc_float_to_u16fp(0.5f) == 0x8000);
+    assert(sc_float_to_u16fp(0.75f) == 0xc000);
+    assert(sc_float_to_u16fp(1.0f) == 0xffff);
+}
+
 int main(int argc, char *argv[]) {
     (void) argc;
     (void) argv;
@@ -77,5 +88,7 @@ int main(int argc, char *argv[]) {
     test_read16be();
     test_read32be();
     test_read64be();
+
+    test_float_to_u16fp();
     return 0;
 }