35 lines
723 B
Go
35 lines
723 B
Go
package main
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import (
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"io"
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"strings"
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"testing"
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)
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func Test_PNG_Reader_Correct_Signature(t *testing.T) {
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const input = "\x89PNG\r\n\x1a\nHELLO"
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out, err := readSignature(input)
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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 out != input {
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t.Fatalf("invalid output, got: '%x'; want: '%x'", out, input)
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}
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}
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func Test_PNG_Reader_Incorrect_Signature(t *testing.T) {
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_, err := readSignature("\x89INCORRECT")
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if err == nil {
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t.Fatal("got: nil; want: !nil err")
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}
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}
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func readSignature(in string) (string, error) {
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r := strings.NewReader(in)
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w := strings.Builder{}
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// _, err := io.Copy(&w, pngReader(r))
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_, err := io.CopyBuffer(&w, pngReader(r), make([]byte, 1))
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return w.String(), err
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}
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