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  	"testing"
		10  	"testing/fstest"
		11  	"time"
		12  )
		13  
		14  var testFsys = fstest.MapFS{
		15  	"hello.txt": {
		16  		Data:		[]byte("hello, world"),
		17  		Mode:		0456,
		18  		ModTime: time.Now(),
		19  		Sys:		 &sysValue,
		20  	},
		21  	"sub/goodbye.txt": {
		22  		Data:		[]byte("goodbye, world"),
		23  		Mode:		0456,
		24  		ModTime: time.Now(),
		25  		Sys:		 &sysValue,
		26  	},
		27  }
		28  
		29  var sysValue int
		30  
		31  type readFileOnly struct{ ReadFileFS }
		32  
		33  func (readFileOnly) Open(name string) (File, error) { return nil, ErrNotExist }
		34  
		35  type openOnly struct{ FS }
		36  
		37  func TestReadFile(t *testing.T) {
		38  	// Test that ReadFile uses the method when present.
		39  	data, err := ReadFile(readFileOnly{testFsys}, "hello.txt")
		40  	if string(data) != "hello, world" || err != nil {
		41  		t.Fatalf(`ReadFile(readFileOnly, "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
		42  	}
		43  
		44  	// Test that ReadFile uses Open when the method is not present.
		45  	data, err = ReadFile(openOnly{testFsys}, "hello.txt")
		46  	if string(data) != "hello, world" || err != nil {
		47  		t.Fatalf(`ReadFile(openOnly, "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
		48  	}
		49  
		50  	// Test that ReadFile on Sub of . works (sub_test checks non-trivial subs).
		51  	sub, err := Sub(testFsys, ".")
		52  	if err != nil {
		53  		t.Fatal(err)
		54  	}
		55  	data, err = ReadFile(sub, "hello.txt")
		56  	if string(data) != "hello, world" || err != nil {
		57  		t.Fatalf(`ReadFile(sub(.), "hello.txt") = %q, %v, want %q, nil`, data, err, "hello, world")
		58  	}
		59  }
		60
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