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package gu
import (
"fmt"
"testing"
)
func TestPtr(t *testing.T) {
sp := Ptr("Hello world!")
if sp == nil {
t.Fatal("Ptr returned nil")
}
}
func ExamplePtr() {
// Pointer of a string
// stringPointer := &"Hello world!": invalid operation: cannot take address of "Hello world!" (untyped string constant)
stringPointer := Ptr("Hello world!")
fmt.Printf("stringPointer is of type %T and points to value %v\n", stringPointer, *stringPointer)
// Constant
const i int64 = 22
// int64Pointer := &i: invalid operation: cannot take address of i (constant 22 of type int64)
int64Pointer := Ptr(i)
fmt.Printf("int64Pointer is of type %T and points to value %v\n", int64Pointer, *int64Pointer)
// Function return
// funcReturn := &fmt.Sprint(99): invalid operation: cannot take address of fmt.Sprint(99) (value of type string)
funcReturn := Ptr(fmt.Sprint(99))
fmt.Printf("funcReturn is of type %T and points to value %v\n", funcReturn, *funcReturn)
// Output: stringPointer is of type *string and points to value Hello world!
// int64Pointer is of type *int64 and points to value 22
// funcReturn is of type *string and points to value 99
}
func TestValue(t *testing.T) {
tests := []struct {
pointer *string
wantValue string
}{
{
nil,
"",
},
{
Ptr("foo"),
"foo",
},
}
for _, tt := range tests {
t.Run(fmt.Sprint(tt.pointer), func(t *testing.T) {
if gotValue := Value(tt.pointer); gotValue != tt.wantValue {
t.Errorf("Value() = %v, want %v", gotValue, tt.wantValue)
}
})
}
}
func ExampleValue() {
type document struct {
ID *int `json:"id,omitempty"`
Description *string `json:"description,omitempty"`
}
d := document{
Description: Ptr("foobar"),
}
// this would panic, d.ID is nil
// fmt.Println(*d.ID, *d.Description)
// d.ID is nil, so a 0 is printed
fmt.Println(Value(d.ID), Value(d.Description))
// Output: 0 foobar
}
func TestPtrCopy(t *testing.T) {
got := PtrCopy[int](nil)
if got != nil {
t.Errorf("PtrCopy(): expected nil, got %v", got)
}
v := Ptr(7)
got = PtrCopy(v)
if got == v {
t.Errorf("PtrCopy(): %v == %v", v, got)
}
}
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