49 lines
1.1 KiB
Go
49 lines
1.1 KiB
Go
package main
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import (
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"io/ioutil"
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"strings"
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"testing"
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)
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func TestCorrectSignature(t *testing.T) {
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const signature = "\x89PNG\r\n\x1a\n"
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const input = signature + "REST OF THE DATA"
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pr := pngReader(strings.NewReader(input))
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out, err := ioutil.ReadAll(pr)
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if err != nil {
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t.Fatalf("got: %q; want: nil err", err)
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}
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if string(out) != input {
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t.Fatalf("got: % x; want: % x", out, input)
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}
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}
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func TestIncorrectSignature(t *testing.T) {
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const input = "WITHOUT PNG SIGNATURE"
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// strings.Reader is a read-only, in-memory stream reader.
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// It's an io.Reader implementation.
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pr := pngReader(strings.NewReader(input))
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// `ioutil.ReadAll` is a dangerous but useful utility function
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// that can read all the data from a reader into memory.
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// Don't use it for large (?) data.
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_, err := ioutil.ReadAll(pr)
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if err == nil {
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t.Fatalf("got: %v; want: !nil err", err)
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}
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}
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func TestSummation(t *testing.T) {
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t.Skip() // skip this test
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result := 1 + 2
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if result != 5 { // it'll always fail
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// t.Fatal("want: 5") // not a good error message
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t.Fatalf("got: %d; want: 5", result) // explanatory error message: good.
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}
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}
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