readfile_test.go

Documentation: io/fs

     1  // Copyright 2020 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 fs_test
     6  
     7  import (
     8  	. "io/fs"
     9  	"os"
    10  	"testing"
    11  	"testing/fstest"
    12  	"time"
    13  )
    14  
    15  var testFsys = fstest.MapFS{
    16  	"hello.txt": {
    17  		Data:    []byte("hello, world"),
    18  		Mode:    0456,
    19  		ModTime: time.Now(),
    20  		Sys:     &sysValue,
    21  	},
    22  	"sub/goodbye.txt": {
    23  		Data:    []byte("goodbye, world"),
    24  		Mode:    0456,
    25  		ModTime: time.Now(),
    26  		Sys:     &sysValue,
    27  	},
    28  }
    29  
    30  var sysValue int
    31  
    32  type readFileOnly struct{ ReadFileFS }
    33  
    34  func (readFileOnly) Open(name string) (File, error) { return nil, ErrNotExist }
    35  
    36  type openOnly struct{ FS }
    37  
    38  func TestReadFile(t *testing.T) {
    39  	// Test that ReadFile uses the method when present.
    40  	data, err := ReadFile(readFileOnly{testFsys}, "hello.txt")
    41  	if string(data) != "hello, world" || err != nil {
    42  		t.Fatalf(`ReadFile(readFileOnly, "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
    43  	}
    44  
    45  	// Test that ReadFile uses Open when the method is not present.
    46  	data, err = ReadFile(openOnly{testFsys}, "hello.txt")
    47  	if string(data) != "hello, world" || err != nil {
    48  		t.Fatalf(`ReadFile(openOnly, "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
    49  	}
    50  
    51  	// Test that ReadFile on Sub of . works (sub_test checks non-trivial subs).
    52  	sub, err := Sub(testFsys, ".")
    53  	if err != nil {
    54  		t.Fatal(err)
    55  	}
    56  	data, err = ReadFile(sub, "hello.txt")
    57  	if string(data) != "hello, world" || err != nil {
    58  		t.Fatalf(`ReadFile(sub(.), "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
    59  	}
    60  }
    61  
    62  func TestReadFilePath(t *testing.T) {
    63  	fsys := os.DirFS(t.TempDir())
    64  	_, err1 := ReadFile(fsys, "non-existent")
    65  	_, err2 := ReadFile(struct{ FS }{fsys}, "non-existent")
    66  	if s1, s2 := errorPath(err1), errorPath(err2); s1 != s2 {
    67  		t.Fatalf("s1: %s != s2: %s", s1, s2)
    68  	}
    69  }
    70
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