map: another fix + test

vlib/builtin/map.v

@@ -57,6 +57,7 @@ fn (m mut map) insert(n mut mapnode, key string, val voidptr) {
 		C.memcpy(n.val, val, m.element_size)
 		if n.is_empty {
 			m.size++
+			n.is_empty = false
 		}
 		return
 	}

vlib/builtin/map_test.v

@@ -91,39 +91,39 @@ fn test_various_map_value() {
 	mut m1 := map[string]int
 	m1['test'] = 1
 	assert m1['test'] == 1
-	
+
 	mut m2 := map[string]string
 	m2['test'] = 'test'
 	assert m2['test'] == 'test'
-	
+
 	mut m3 := map[string]i8
 	m3['test'] = i8(0)
 	assert m3['test'] == i8(0)
-	
+
 	mut m4 := map[string]i16
 	m4['test'] = i16(0)
 	assert m4['test'] == i16(0)
-	
+
 	mut m7 := map[string]u16
 	m7['test'] = u16(0)
 	assert m7['test'] == u16(0)
-	
+
 	mut m8 := map[string]u32
 	m8['test'] = u32(0)
 	assert m8['test'] == u32(0)
-	
+
 	mut m9 := map[string]bool
 	m9['test'] = true
 	assert m9['test'] == true
-	
+
 	mut m10 := map[string]byte
 	m10['test'] = byte(0)
 	assert m10['test'] == byte(0)
-	
+
 	mut m11 := map[string]f32
 	m11['test'] = f32(0.0)
 	assert m11['test'] == f32(0.0)
-	
+
 	mut m12 := map[string]f64
 	m12['test'] = f64(0.0)
 	assert m12['test'] == f64(0.0)
@@ -177,7 +177,7 @@ fn test_delete() {
 	println(m['two']) // => 0
 	assert 'two' in m == false
 	println('two' in m) // => true, on Linux  and Windows  <-- wrong !
-}	
+}
 
 /*
 fn test_ref() {
@@ -186,6 +186,22 @@ fn test_ref() {
 	mut one := &m['one']
 	one++
 	println(*one)
-	
+
 }
 */
+
+fn test_delete_size() {
+    arr := ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
+    mut m := map[string]int
+    for _ in 0..10 {
+        for i in 0..10 {
+            m[arr[i]] = i
+        }
+        assert(m.size == 10)
+        println(m.size)
+        for i in 0..10 {
+            m.delete(arr[i])
+        }
+    }
+}
+