pkg/fileutils: add verifications and unit test for SymboliLlink

pkg/fileutils/fileutils.go

@@ -94,7 +94,18 @@ func Link(src string, linkName string) error {
 
 // SymbolicLink creates target as a symbolic link to src.
 func SymbolicLink(src string, target string) error {
-	// TODO Add verifications.
+	if !PathExist(src) {
+		return fmt.Errorf("failed to symlink %s to %s: src no such file or directory", target, src)
+	}
+	if PathExist(target) {
+		if IsDir(target) {
+			return fmt.Errorf("failed to symlink %s to %s: link name already exists and is a directory", target, src)
+		}
+		if err := DeleteFile(target); err != nil {
+			return fmt.Errorf("failed to symlink %s to %s when deleting target file: %v", target, src, err)
+		}
+
+	}
 	return os.Symlink(src, target)
 }
 

pkg/fileutils/fileutils_test.go

@@ -181,6 +181,38 @@ func (s *FileUtilTestSuite) TestLink(c *check.C) {
 	c.Assert(err, check.NotNil)
 }
 
+func (s *FileUtilTestSuite) TestSymbolicLink(c *check.C) {
+	pathStr := filepath.Join(s.tmpDir, "TestSymLinkFileNonExist")
+	linkStr := filepath.Join(s.tmpDir, "TestSymLinkNameFileNonExist")
+	err := SymbolicLink(pathStr, linkStr)
+	c.Assert(err, check.NotNil)
+	c.Assert(PathExist(linkStr), check.Equals, false)
+
+	pathStr = filepath.Join(s.tmpDir, "TestSymLinkDir")
+	os.Mkdir(pathStr, 0755)
+	linkStr = filepath.Join(s.tmpDir, "TestSymLinkNameDir")
+	err = SymbolicLink(pathStr, linkStr)
+	c.Assert(err, check.IsNil)
+	c.Assert(PathExist(linkStr), check.Equals, true)
+
+	pathStr = filepath.Join(s.tmpDir, "TestSymLinkFile")
+	os.Create(pathStr)
+	linkStr = filepath.Join(s.tmpDir, "TestSymLinkNameFile")
+	err = SymbolicLink(pathStr, linkStr)
+	c.Assert(err, check.IsNil)
+	c.Assert(PathExist(linkStr), check.Equals, true)
+
+	linkStr = filepath.Join(s.tmpDir, "TestSymLinkNameDirExist")
+	os.Mkdir(linkStr, 0755)
+	err = SymbolicLink(pathStr, linkStr)
+	c.Assert(err, check.NotNil)
+
+	linkStr = filepath.Join(s.tmpDir, "TestSymLinkNameFileExist")
+	os.Create(linkStr)
+	err = SymbolicLink(pathStr, linkStr)
+	c.Assert(err, check.IsNil)
+}
+
 func (s *FileUtilTestSuite) TestCopyFile(c *check.C) {
 	srcPath := filepath.Join(s.tmpDir, "TestCopyFileSrc")
 	dstPath := filepath.Join(s.tmpDir, "TestCopyFileDst")