unix: Add some extra coverage tests for vstr and attrtuple.

tests/unix/extra_coverage.py.exp

+# vstr
+tests
+sts
+
+test
+tes
+larg
+# repl
 ame__
 
 __name__        path            argv            version
@@ -5,3 +13,5 @@ version_info    implementation  platform        byteorder
 maxsize         exit            stdin           stdout
 stderr          exc_info        print_exception
 ementation
+# attrtuple
+(start=1, stop=2, step=3)

unix/coverage.c

@@ -8,8 +8,38 @@
 
 // function to run extra tests for things that can't be checked by scripts
 STATIC mp_obj_t extra_coverage(void) {
+    // vstr
+    {
+        printf("# vstr\n");
+        vstr_t *vstr = vstr_new_size(16);
+        vstr_hint_size(vstr, 32);
+        vstr_add_str(vstr, "ts");
+        vstr_ins_byte(vstr, 1, 'e');
+        vstr_ins_char(vstr, 3, 't');
+        vstr_ins_char(vstr, 10, 's');
+        printf("%.*s\n", (int)vstr->len, vstr->buf);
+
+        vstr_cut_head_bytes(vstr, 2);
+        printf("%.*s\n", (int)vstr->len, vstr->buf);
+
+        vstr_cut_tail_bytes(vstr, 10);
+        printf("%.*s\n", (int)vstr->len, vstr->buf);
+
+        vstr_printf(vstr, "t%cst", 'e');
+        printf("%.*s\n", (int)vstr->len, vstr->buf);
+
+        vstr_cut_out_bytes(vstr, 3, 10);
+        printf("%.*s\n", (int)vstr->len, vstr->buf);
+
+        VSTR_FIXED(fix, 4);
+        vstr_add_str(&fix, "large");
+        printf("%.*s\n", (int)fix.len, fix.buf);
+    }
+
     // repl autocomplete
     {
+        printf("# repl\n");
+
         const char *str;
         mp_uint_t len = mp_repl_autocomplete("__n", 3, &mp_plat_print, &str);
         printf("%.*s\n", (int)len, str);
@@ -20,6 +50,16 @@ STATIC mp_obj_t extra_coverage(void) {
         printf("%.*s\n", (int)len, str);
     }
 
+    // attrtuple
+    {
+        printf("# attrtuple\n");
+
+        static const qstr fields[] = {MP_QSTR_start, MP_QSTR_stop, MP_QSTR_step};
+        static const mp_obj_t items[] = {MP_OBJ_NEW_SMALL_INT(1), MP_OBJ_NEW_SMALL_INT(2), MP_OBJ_NEW_SMALL_INT(3)};
+        mp_obj_print_helper(&mp_plat_print, mp_obj_new_attrtuple(fields, 3, items), PRINT_REPR);
+        printf("\n");
+    }
+
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_0(extra_coverage_obj, extra_coverage);