Empty
Empty operator checks that an array, a channel, a map, a slice or a
string is empty. As a special case (non-typed) nil, as well as nil
channel, map or slice are considered empty.
Note that the compared data can be a pointer (of pointer of pointer
etc.) on an array, a channel, a map, a slice or a string.
td.Cmp(t, "", td.Empty()) // succeeds
td.Cmp(t, map[string]bool{}, td.Empty()) // succeeds
td.Cmp(t, []string{"foo"}, td.Empty()) // fails
See also Empty godoc.
Examples
Base example
t := &testing.T{}
ok := td.Cmp(t, nil, td.Empty()) // special case: nil is considered empty
fmt.Println(ok)
// fails, typed nil is not empty (expect for channel, map, slice or
// pointers on array, channel, map slice and strings)
ok = td.Cmp(t, (*int)(nil), td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, "", td.Empty())
fmt.Println(ok)
// Fails as 0 is a number, so not empty. Use Zero() instead
ok = td.Cmp(t, 0, td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, (map[string]int)(nil), td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, map[string]int{}, td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, ([]int)(nil), td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, []int{}, td.Empty())
fmt.Println(ok)
ok = td.Cmp(t, []int{3}, td.Empty()) // fails, as not empty
fmt.Println(ok)
ok = td.Cmp(t, [3]int{}, td.Empty()) // fails, Empty() is not Zero()!
fmt.Println(ok)
// Output:
// true
// false
// true
// false
// true
// true
// true
// true
// false
// false
Pointers example
t := &testing.T{}
type MySlice []int
ok := td.Cmp(t, MySlice{}, td.Empty()) // Ptr() not needed
fmt.Println(ok)
ok = td.Cmp(t, &MySlice{}, td.Empty())
fmt.Println(ok)
l1 := &MySlice{}
l2 := &l1
l3 := &l2
ok = td.Cmp(t, &l3, td.Empty())
fmt.Println(ok)
// Works the same for array, map, channel and string
// But not for others types as:
type MyStruct struct {
Value int
}
ok = td.Cmp(t, &MyStruct{}, td.Empty()) // fails, use Zero() instead
fmt.Println(ok)
// Output:
// true
// true
// true
// false
CmpEmpty shortcut
func CmpEmpty(t TestingT, got any, args ...any) bool
CmpEmpty is a shortcut for:
td.Cmp(t, got, td.Empty(), args...)
See above for details.
Returns true if the test is OK, false if it fails.
If t is a *T then its Config field is inherited.
args… are optional and allow to name the test. This name is
used in case of failure to qualify the test. If len(args) > 1 and
the first item of args is a string and contains a ‘%’ rune then
fmt.Fprintf is used to compose the name, else args are passed to
fmt.Fprint. Do not forget it is the name of the test, not the
reason of a potential failure.
See also CmpEmpty godoc.
Examples
Base example
t := &testing.T{}
ok := td.CmpEmpty(t, nil) // special case: nil is considered empty
fmt.Println(ok)
// fails, typed nil is not empty (expect for channel, map, slice or
// pointers on array, channel, map slice and strings)
ok = td.CmpEmpty(t, (*int)(nil))
fmt.Println(ok)
ok = td.CmpEmpty(t, "")
fmt.Println(ok)
// Fails as 0 is a number, so not empty. Use Zero() instead
ok = td.CmpEmpty(t, 0)
fmt.Println(ok)
ok = td.CmpEmpty(t, (map[string]int)(nil))
fmt.Println(ok)
ok = td.CmpEmpty(t, map[string]int{})
fmt.Println(ok)
ok = td.CmpEmpty(t, ([]int)(nil))
fmt.Println(ok)
ok = td.CmpEmpty(t, []int{})
fmt.Println(ok)
ok = td.CmpEmpty(t, []int{3}) // fails, as not empty
fmt.Println(ok)
ok = td.CmpEmpty(t, [3]int{}) // fails, Empty() is not Zero()!
fmt.Println(ok)
// Output:
// true
// false
// true
// false
// true
// true
// true
// true
// false
// false
Pointers example
t := &testing.T{}
type MySlice []int
ok := td.CmpEmpty(t, MySlice{}) // Ptr() not needed
fmt.Println(ok)
ok = td.CmpEmpty(t, &MySlice{})
fmt.Println(ok)
l1 := &MySlice{}
l2 := &l1
l3 := &l2
ok = td.CmpEmpty(t, &l3)
fmt.Println(ok)
// Works the same for array, map, channel and string
// But not for others types as:
type MyStruct struct {
Value int
}
ok = td.CmpEmpty(t, &MyStruct{}) // fails, use Zero() instead
fmt.Println(ok)
// Output:
// true
// true
// true
// false
T.Empty shortcut
func (t *T) Empty(got any, args ...any) bool
Empty is a shortcut for:
t.Cmp(got, td.Empty(), args...)
See above for details.
Returns true if the test is OK, false if it fails.
args… are optional and allow to name the test. This name is
used in case of failure to qualify the test. If len(args) > 1 and
the first item of args is a string and contains a ‘%’ rune then
fmt.Fprintf is used to compose the name, else args are passed to
fmt.Fprint. Do not forget it is the name of the test, not the
reason of a potential failure.
See also T.Empty godoc.
Examples
Base example
t := td.NewT(&testing.T{})
ok := t.Empty(nil) // special case: nil is considered empty
fmt.Println(ok)
// fails, typed nil is not empty (expect for channel, map, slice or
// pointers on array, channel, map slice and strings)
ok = t.Empty((*int)(nil))
fmt.Println(ok)
ok = t.Empty("")
fmt.Println(ok)
// Fails as 0 is a number, so not empty. Use Zero() instead
ok = t.Empty(0)
fmt.Println(ok)
ok = t.Empty((map[string]int)(nil))
fmt.Println(ok)
ok = t.Empty(map[string]int{})
fmt.Println(ok)
ok = t.Empty(([]int)(nil))
fmt.Println(ok)
ok = t.Empty([]int{})
fmt.Println(ok)
ok = t.Empty([]int{3}) // fails, as not empty
fmt.Println(ok)
ok = t.Empty([3]int{}) // fails, Empty() is not Zero()!
fmt.Println(ok)
// Output:
// true
// false
// true
// false
// true
// true
// true
// true
// false
// false
Pointers example
t := td.NewT(&testing.T{})
type MySlice []int
ok := t.Empty(MySlice{}) // Ptr() not needed
fmt.Println(ok)
ok = t.Empty(&MySlice{})
fmt.Println(ok)
l1 := &MySlice{}
l2 := &l1
l3 := &l2
ok = t.Empty(&l3)
fmt.Println(ok)
// Works the same for array, map, channel and string
// But not for others types as:
type MyStruct struct {
Value int
}
ok = t.Empty(&MyStruct{}) // fails, use Zero() instead
fmt.Println(ok)
// Output:
// true
// true
// true
// false