tests: fix some tests, that failed due to the stricter immutable checks

vlib/encoding/csv/writer.v

@@ -7,6 +7,7 @@ module csv
 import strings
 
 struct Writer {
+mut:
 	sb strings.Builder
 pub mut:
 	use_crlf bool

vlib/eventbus/eventbus.v

@@ -28,7 +28,6 @@ pub struct EventBus {
 pub mut:
 	registry   &Registry
 	publisher  &Publisher
-pub:
 	subscriber &Subscriber
 }
 

vlib/net/websocket/ws.v

@@ -15,12 +15,12 @@ pub struct Client {
 	retry      int
 	eb         &eventbus.EventBus
 	is_ssl     bool
-	lock       &sync.Mutex = sync.new_mutex()
-	write_lock &sync.Mutex = sync.new_mutex()
 	// subprotocol_len int
 	// cwebsocket_subprotocol *subprotocol;
 	// cwebsocket_subprotocol *subprotocols[];
 mut:
+	lock       &sync.Mutex = sync.new_mutex()
+	write_lock &sync.Mutex = sync.new_mutex()
 	state      State
 	socket     net.Socket
 	flags      []Flag

vlib/time/stopwatch_test.v

@@ -4,7 +4,7 @@ import time
 // time than you have specified. To avoid false positives from CI test
 // failures, some of the asserts will be run only if you pass `-d stopwatch`
 fn test_stopwatch_works_as_intended() {
-	sw := time.new_stopwatch({})
+	mut sw := time.new_stopwatch({})
 	// sample code that you want to measure:
 	println('Hello world')
 	time.sleep_ms(1)
@@ -15,7 +15,7 @@ fn test_stopwatch_works_as_intended() {
 
 fn test_stopwatch_time_between_pause_and_start_should_be_skipped_in_elapsed() {
 	println('Testing pause function')
-	sw := time.new_stopwatch({})
+	mut sw := time.new_stopwatch({})
 	time.sleep_ms(10) // A
 	eprintln('Elapsed after 10ms nap: ${sw.elapsed().milliseconds()}ms')
 	assert sw.elapsed().milliseconds() >= 10

vlib/v/checker/tests/const_field_add_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/const_field_add_err.v:6:2: error: cannot assign to constant `a` 
+vlib/v/checker/tests/const_field_add_err.v:6:2: error: cannot modify constant `a`
     4 | 
     5 | fn main() {
     6 |     a += 1

vlib/v/checker/tests/const_field_dec_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/const_field_dec_err.v:6:2: error: cannot assign to constant `a` 
+vlib/v/checker/tests/const_field_dec_err.v:6:2: error: cannot modify constant `a`
     4 | 
     5 | fn main() {
     6 |     a--

vlib/v/checker/tests/const_field_inc_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/const_field_inc_err.v:6:2: error: cannot assign to constant `a` 
+vlib/v/checker/tests/const_field_inc_err.v:6:2: error: cannot modify constant `a` 
     4 | 
     5 | fn main() {
     6 |     a++

vlib/v/checker/tests/const_field_sub_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/const_field_sub_err.v:6:2: error: cannot assign to constant `a` 
+vlib/v/checker/tests/const_field_sub_err.v:6:2: error: cannot modify constant `a`
     4 | 
     5 | fn main() {
     6 |     a -= 1

vlib/v/fmt/fmt.v

@@ -16,10 +16,10 @@ const (
 
 pub struct Fmt {
 pub:
-	out               strings.Builder
-	out_imports       strings.Builder
 	table             &table.Table
 pub mut:
+	out_imports       strings.Builder
+	out               strings.Builder
 	indent            int
 	empty_line        bool
 	line_len          int

vlib/v/scanner/scanner_test.v

@@ -89,7 +89,7 @@ fn test_scan() {
 		assert t == 2
 	})
 
-	tfn := TestFn{}
+	mut tfn := TestFn{}
 	tfn.tst_1()
 	tfn.tst_2(fn(i int){
 		t := i + 1
@@ -102,7 +102,7 @@ fn test_scan() {
 	// Test @STRUCT
 	assert @STRUCT == ''
 
-	ts := TestStruct { test: "test" }
+	mut ts := TestStruct { test: "test" }
 	ts.test_struct()
 	r1 := ts.test_struct_w_return()
 	r2 := ts.test_struct_w_high_order(fn(i int)string{

vlib/v/tests/live_test.v

@@ -46,7 +46,7 @@ import os
 import live
 
 fn append_to_file(fname, s string) {
-	f := os.open_append(fname) or {
+	mut f := os.open_append(fname) or {
 		println('>>>> could not open file \$fname for appending, err: \$err ')
 		return 
 	}