Get rid of helpers.go

fileutils.go

@@ -7,6 +7,20 @@ import (
 	"path"
 )
 
+// IsExists reports whether path exists (path may be a file or a directory).
+func IsExists(stater Stater, path string) (bool, error) {
+	_, err := stater.Stat(path)
+	if stater.IsNotExist(err) {
+		return false, nil
+	}
+
+	if err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
 // Copy copies a file from src to dst.
 func Copy(src, dst string) error {
 	sfi, err := os.Lstat(src)

fileutils_test.go

@@ -1,12 +1,65 @@
 package main
 
 import (
+	"errors"
 	"io/ioutil"
 	"os"
 	"path"
+	"reflect"
 	"testing"
 )
 
+func TestIsExists(t *testing.T) {
+	cases := []struct {
+		stater         *FakeStater
+		name           string
+		expectedResult bool
+		expectedError  error
+	}{
+		{
+			stater: &FakeStater{
+				StatFileInfo:     nil, // does not matter
+				StatError:        errors.New("Permission denied"),
+				IsNotExistResult: false,
+			},
+			name:           "/path/that/errors/on/stat",
+			expectedResult: false,
+			expectedError:  errors.New("Permission denied"),
+		},
+		{
+			stater: &FakeStater{
+				StatFileInfo:     nil, // does not matter
+				StatError:        errors.New("Not exists"),
+				IsNotExistResult: true,
+			},
+			name:           "/path/that/exists",
+			expectedResult: false,
+			expectedError:  nil,
+		},
+		{
+			stater: &FakeStater{
+				StatFileInfo:     nil, // does not matter
+				StatError:        nil,
+				IsNotExistResult: false,
+			},
+			name:           "/path/that/not/exists",
+			expectedResult: true,
+			expectedError:  nil,
+		},
+	}
+
+	for _, testcase := range cases {
+		exists, err := IsExists(testcase.stater, testcase.name)
+		if exists != testcase.expectedResult {
+			t.Errorf("Expected %v but got %v\n", testcase.expectedResult, exists)
+		}
+
+		if !reflect.DeepEqual(err, testcase.expectedError) {
+			t.Errorf("Expected err to be %v but it was %v\n", testcase.expectedError, err)
+		}
+	}
+}
+
 func TestCopy(t *testing.T) {
 	testCopyPositive(t)
 	testCopyNegativeLstat(t)

fs.go

@@ -8,6 +8,27 @@ type DirMaker interface {
 	MkdirAll(path string, perm os.FileMode) error
 }
 
+type Symlinker interface {
+	Symlink(oldname, newname string) error
+}
+
+type Stater interface {
+	Stat(name string) (os.FileInfo, error)
+	IsNotExist(err error) bool
+}
+
+type FakeMkdirSymlinker struct {
+	*FakeDirMaker
+	*FakeSymlinker
+}
+
+type StatDirMaker interface {
+	Stater
+	DirMaker
+}
+
+// Fake implementation of interface
+
 type FakeDirMaker struct {
 	MkdirAllError error
 }
@@ -16,10 +37,6 @@ func (f *FakeDirMaker) MkdirAll(path string, perm os.FileMode) error {
 	return f.MkdirAllError
 }
 
-type Symlinker interface {
-	Symlink(oldname, newname string) error
-}
-
 type FakeSymlinker struct {
 	SymlinkError error
 }
@@ -28,24 +45,23 @@ func (f *FakeSymlinker) Symlink(oldname, newname string) error {
 	return f.SymlinkError
 }
 
-type Stater interface {
-	Stat(name string) (os.FileInfo, error)
-	IsNotExist(err error) bool
+type FakeStater struct {
+	StatFileInfo     os.FileInfo
+	StatError        error
+	IsNotExistResult bool
 }
 
-type MkdirSymlinker interface {
-	DirMaker
-	Symlinker
+func (f *FakeStater) Stat(name string) (os.FileInfo, error) {
+	return f.StatFileInfo, f.StatError
 }
 
-type FakeMkdirSymlinker struct {
-	*FakeDirMaker
-	*FakeSymlinker
+func (f *FakeStater) IsNotExist(err error) bool {
+	return f.IsNotExistResult
 }
 
-type StatDirMaker interface {
-	Stater
+type MkdirSymlinker interface {
 	DirMaker
+	Symlinker
 }
 
 // Actual implementation of interface using os package.
@@ -57,8 +73,7 @@ func (f *OsDirMaker) MkdirAll(path string, perm os.FileMode) error {
 	return os.MkdirAll(path, perm)
 }
 
-type OsSymlinker struct {
-}
+type OsSymlinker struct{}
 
 func (f *OsSymlinker) Symlink(oldname, newname string) error {
 	return os.Symlink(oldname, newname)
@@ -68,3 +83,13 @@ type OsMkdirSymlinker struct {
 	*OsDirMaker
 	*OsSymlinker
 }
+
+type OsStater struct{}
+
+func (s *OsStater) Stat(name string) (os.FileInfo, error) {
+	return os.Stat(name)
+}
+
+func (s *OsStater) IsNotExist(err error) bool {
+	return os.IsNotExist(err)
+}