format.go

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package testtrace
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"internal/trace/raw"
    11  	"internal/txtar"
    12  	"io"
    13  )
    14  
    15  // ParseFile parses a test file generated by the testgen package.
    16  func ParseFile(testPath string) (io.Reader, *Expectation, error) {
    17  	ar, err := txtar.ParseFile(testPath)
    18  	if err != nil {
    19  		return nil, nil, fmt.Errorf("failed to read test file for %s: %v", testPath, err)
    20  	}
    21  	if len(ar.Files) != 2 {
    22  		return nil, nil, fmt.Errorf("malformed test %s: wrong number of files", testPath)
    23  	}
    24  	if ar.Files[0].Name != "expect" {
    25  		return nil, nil, fmt.Errorf("malformed test %s: bad filename %s", testPath, ar.Files[0].Name)
    26  	}
    27  	if ar.Files[1].Name != "trace" {
    28  		return nil, nil, fmt.Errorf("malformed test %s: bad filename %s", testPath, ar.Files[1].Name)
    29  	}
    30  	tr, err := raw.NewTextReader(bytes.NewReader(ar.Files[1].Data))
    31  	if err != nil {
    32  		return nil, nil, fmt.Errorf("malformed test %s: bad trace file: %v", testPath, err)
    33  	}
    34  	var buf bytes.Buffer
    35  	tw, err := raw.NewWriter(&buf, tr.Version())
    36  	if err != nil {
    37  		return nil, nil, fmt.Errorf("failed to create trace byte writer: %v", err)
    38  	}
    39  	for {
    40  		ev, err := tr.ReadEvent()
    41  		if err == io.EOF {
    42  			break
    43  		}
    44  		if err != nil {
    45  			return nil, nil, fmt.Errorf("malformed test %s: bad trace file: %v", testPath, err)
    46  		}
    47  		if err := tw.WriteEvent(ev); err != nil {
    48  			return nil, nil, fmt.Errorf("internal error during %s: failed to write trace bytes: %v", testPath, err)
    49  		}
    50  	}
    51  	exp, err := ParseExpectation(ar.Files[0].Data)
    52  	if err != nil {
    53  		return nil, nil, fmt.Errorf("internal error during %s: failed to parse expectation %q: %v", testPath, string(ar.Files[0].Data), err)
    54  	}
    55  	return &buf, exp, nil
    56  }
    57
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