vendor/github.com/pkg/errors/example_test.go

   1 package errors_test
   2
   3 import (
   4         "fmt"
   5
   6         "github.com/pkg/errors"
   7 )
   8
   9 func ExampleNew() {
  10         err := errors.New("whoops")
  11         fmt.Println(err)
  12
  13         // Output: whoops
  14 }
  15
  16 func ExampleNew_printf() {
  17         err := errors.New("whoops")
  18         fmt.Printf("%+v", err)
  19
  20         // Example output:
  21         // whoops
  22         // github.com/pkg/errors_test.ExampleNew_printf
  23         //         /home/dfc/src/github.com/pkg/errors/example_test.go:17
  24         // testing.runExample
  25         //         /home/dfc/go/src/testing/example.go:114
  26         // testing.RunExamples
  27         //         /home/dfc/go/src/testing/example.go:38
  28         // testing.(*M).Run
  29         //         /home/dfc/go/src/testing/testing.go:744
  30         // main.main
  31         //         /github.com/pkg/errors/_test/_testmain.go:106
  32         // runtime.main
  33         //         /home/dfc/go/src/runtime/proc.go:183
  34         // runtime.goexit
  35         //         /home/dfc/go/src/runtime/asm_amd64.s:2059
  36 }
  37
  38 func ExampleWithMessage() {
  39         cause := errors.New("whoops")
  40         err := errors.WithMessage(cause, "oh noes")
  41         fmt.Println(err)
  42
  43         // Output: oh noes: whoops
  44 }
  45
  46 func ExampleWithStack() {
  47         cause := errors.New("whoops")
  48         err := errors.WithStack(cause)
  49         fmt.Println(err)
  50
  51         // Output: whoops
  52 }
  53
  54 func ExampleWithStack_printf() {
  55         cause := errors.New("whoops")
  56         err := errors.WithStack(cause)
  57         fmt.Printf("%+v", err)
  58
  59         // Example Output:
  60         // whoops
  61         // github.com/pkg/errors_test.ExampleWithStack_printf
  62         //         /home/fabstu/go/src/github.com/pkg/errors/example_test.go:55
  63         // testing.runExample
  64         //         /usr/lib/go/src/testing/example.go:114
  65         // testing.RunExamples
  66         //         /usr/lib/go/src/testing/example.go:38
  67         // testing.(*M).Run
  68         //         /usr/lib/go/src/testing/testing.go:744
  69         // main.main
  70         //         github.com/pkg/errors/_test/_testmain.go:106
  71         // runtime.main
  72         //         /usr/lib/go/src/runtime/proc.go:183
  73         // runtime.goexit
  74         //         /usr/lib/go/src/runtime/asm_amd64.s:2086
  75         // github.com/pkg/errors_test.ExampleWithStack_printf
  76         //         /home/fabstu/go/src/github.com/pkg/errors/example_test.go:56
  77         // testing.runExample
  78         //         /usr/lib/go/src/testing/example.go:114
  79         // testing.RunExamples
  80         //         /usr/lib/go/src/testing/example.go:38
  81         // testing.(*M).Run
  82         //         /usr/lib/go/src/testing/testing.go:744
  83         // main.main
  84         //         github.com/pkg/errors/_test/_testmain.go:106
  85         // runtime.main
  86         //         /usr/lib/go/src/runtime/proc.go:183
  87         // runtime.goexit
  88         //         /usr/lib/go/src/runtime/asm_amd64.s:2086
  89 }
  90
  91 func ExampleWrap() {
  92         cause := errors.New("whoops")
  93         err := errors.Wrap(cause, "oh noes")
  94         fmt.Println(err)
  95
  96         // Output: oh noes: whoops
  97 }
  98
  99 func fn() error {
 100         e1 := errors.New("error")
 101         e2 := errors.Wrap(e1, "inner")
 102         e3 := errors.Wrap(e2, "middle")
 103         return errors.Wrap(e3, "outer")
 104 }
 105
 106 func ExampleCause() {
 107         err := fn()
 108         fmt.Println(err)
 109         fmt.Println(errors.Cause(err))
 110
 111         // Output: outer: middle: inner: error
 112         // error
 113 }
 114
 115 func ExampleWrap_extended() {
 116         err := fn()
 117         fmt.Printf("%+v\n", err)
 118
 119         // Example output:
 120         // error
 121         // github.com/pkg/errors_test.fn
 122         //         /home/dfc/src/github.com/pkg/errors/example_test.go:47
 123         // github.com/pkg/errors_test.ExampleCause_printf
 124         //         /home/dfc/src/github.com/pkg/errors/example_test.go:63
 125         // testing.runExample
 126         //         /home/dfc/go/src/testing/example.go:114
 127         // testing.RunExamples
 128         //         /home/dfc/go/src/testing/example.go:38
 129         // testing.(*M).Run
 130         //         /home/dfc/go/src/testing/testing.go:744
 131         // main.main
 132         //         /github.com/pkg/errors/_test/_testmain.go:104
 133         // runtime.main
 134         //         /home/dfc/go/src/runtime/proc.go:183
 135         // runtime.goexit
 136         //         /home/dfc/go/src/runtime/asm_amd64.s:2059
 137         // github.com/pkg/errors_test.fn
 138         //        /home/dfc/src/github.com/pkg/errors/example_test.go:48: inner
 139         // github.com/pkg/errors_test.fn
 140         //        /home/dfc/src/github.com/pkg/errors/example_test.go:49: middle
 141         // github.com/pkg/errors_test.fn
 142         //      /home/dfc/src/github.com/pkg/errors/example_test.go:50: outer
 143 }
 144
 145 func ExampleWrapf() {
 146         cause := errors.New("whoops")
 147         err := errors.Wrapf(cause, "oh noes #%d", 2)
 148         fmt.Println(err)
 149
 150         // Output: oh noes #2: whoops
 151 }
 152
 153 func ExampleErrorf_extended() {
 154         err := errors.Errorf("whoops: %s", "foo")
 155         fmt.Printf("%+v", err)
 156
 157         // Example output:
 158         // whoops: foo
 159         // github.com/pkg/errors_test.ExampleErrorf
 160         //         /home/dfc/src/github.com/pkg/errors/example_test.go:101
 161         // testing.runExample
 162         //         /home/dfc/go/src/testing/example.go:114
 163         // testing.RunExamples
 164         //         /home/dfc/go/src/testing/example.go:38
 165         // testing.(*M).Run
 166         //         /home/dfc/go/src/testing/testing.go:744
 167         // main.main
 168         //         /github.com/pkg/errors/_test/_testmain.go:102
 169         // runtime.main
 170         //         /home/dfc/go/src/runtime/proc.go:183
 171         // runtime.goexit
 172         //         /home/dfc/go/src/runtime/asm_amd64.s:2059
 173 }
 174
 175 func Example_stackTrace() {
 176         type stackTracer interface {
 177                 StackTrace() errors.StackTrace
 178         }
 179
 180         err, ok := errors.Cause(fn()).(stackTracer)
 181         if !ok {
 182                 panic("oops, err does not implement stackTracer")
 183         }
 184
 185         st := err.StackTrace()
 186         fmt.Printf("%+v", st[0:2]) // top two frames
 187
 188         // Example output:
 189         // github.com/pkg/errors_test.fn
 190         //      /home/dfc/src/github.com/pkg/errors/example_test.go:47
 191         // github.com/pkg/errors_test.Example_stackTrace
 192         //      /home/dfc/src/github.com/pkg/errors/example_test.go:127
 193 }
 194
 195 func ExampleCause_printf() {
 196         err := errors.Wrap(func() error {
 197                 return func() error {
 198                         return errors.Errorf("hello %s", fmt.Sprintf("world"))
 199                 }()
 200         }(), "failed")
 201
 202         fmt.Printf("%v", err)
 203
 204         // Output: failed: hello world
 205 }