Improve error output in case local version is not installed

Fixes #38

bin/ec-proxy/main.go

@@ -33,21 +33,33 @@ func setCmd(cmd *exec.Cmd, name, version string) {
 	cmd.Stdin = os.Stdin
 }
 
+// Get relative path to the dot file
+func getRelativePath(dotPath string) string {
+	cwd, err := os.Getwd()
+	print.Error(err)
+
+	dir, err := filepath.Rel(filepath.Dir(cwd), cwd)
+	print.Error(err)
+
+	return "./" + filepath.Join(dir, filepath.Base(dotPath))
+}
+
 func main() {
 	_, name := path.Split(os.Args[0])
 
 	language := plugins.SearchBin(name)
 	dotFiles := plugins.Dots(language)
 	base := variables.Home()
 
-	version, err := io.GetVersion(dotFiles)
+	version, dotPath, err := io.GetVersion(dotFiles)
 	print.Error(err)
 
 	pathPart := filepath.Join(base, language, version)
 	binPath := filepath.Join(pathPart, "bin", name)
 
 	if _, err := os.Stat(binPath); os.IsNotExist(err) {
-		err = errors.New("Version " + version + " has not been established")
+		err = errors.New("Version \"" + version + "\" was defined on \"" +
+			getRelativePath(dotPath) + "\" path but this version is not installed")
 		print.Error(err)
 	}
 

bin/ec/main_test.go

@@ -80,7 +80,7 @@ var _ = Describe("main", func() {
 			})
 		})
 
-		Describe("local install", func() {
+		Describe("local", func() {
 			It("should install version but don't switch to it globally", func() {
 				current := Command("go", "run", path, "ls", "node")
 
@@ -108,6 +108,24 @@ var _ = Describe("main", func() {
 				Expect(strings.Contains(string(upperRes), "♥ 6.5.0")).To(Equal(true))
 				Expect(strings.Contains(string(upperRes), "6.4.0")).To(Equal(true))
 			})
+
+			It("should provide more or less error message if local install is not there", func() {
+				pwd, _ := os.Getwd()
+				versionFile := filepath.Join(pwd, ".node-version")
+
+				Command("go", "run", path, "rm", "node@6.3.0")
+
+				io.WriteFile(versionFile, "6.3.0")
+
+				result, _ := Command("node", "-v").CombinedOutput()
+
+				expected := string(result)
+				actual := "Version \"6.3.0\" was defined on \"./ec/.node-version\" path but this version is not installed"
+
+				Expect(expected).To(ContainSubstring(actual))
+
+				os.RemoveAll(versionFile)
+			})
 		})
 	})
 

cmd/commands/ls/ls.go

@@ -65,7 +65,7 @@ func listLocalVersions(language string) {
 	versions, err := plugin.List()
 	print.Error(err)
 
-	current, err := io.GetVersion(plugin.Dots())
+	current, _, err := io.GetVersion(plugin.Dots())
 	print.Error(err)
 
 	// In case we could find `.<language>-version` file i.e. there is no local version

io/io.go

@@ -33,9 +33,7 @@ func walkUp(path string, fn Walker) {
 	return
 }
 
-func GetVersion(args ...interface{}) (version string, err error) {
-	var path string
-
+func GetVersion(args ...interface{}) (version, path string, err error) {
 	if len(args) > 1 {
 		path, err = FindDotFile(args[0], args[1])
 	} else {
@@ -47,7 +45,7 @@ func GetVersion(args ...interface{}) (version string, err error) {
 	}
 
 	if _, err := os.Stat(path); os.IsNotExist(err) {
-		return "current", nil
+		return "current", "", nil
 	}
 
 	file, err := os.Open(path)
@@ -59,14 +57,14 @@ func GetVersion(args ...interface{}) (version string, err error) {
 
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
-		return scanner.Text(), nil
+		return scanner.Text(), path, nil
 	}
 
 	if scannerErr := scanner.Err(); scannerErr != nil {
-		return "", scannerErr
+		return "", "", scannerErr
 	}
 
-	return "current", nil
+	return "current", "", nil
 }
 
 func FindDotFile(args ...interface{}) (versionPath string, err error) {

io/io_test.go

@@ -26,8 +26,9 @@ var _ = Describe("io", func() {
 		It("Should get version for node from .nvmrc file", func() {
 			dots := plugins.Dots("node")
 			path, _ := filepath.Abs("../testdata/io/node-with-nvm/")
-			result, _ := GetVersion(dots, path)
+			result, dotPath, _ := GetVersion(dots, path)
 
+			Expect(dotPath).To(ContainSubstring("io/node-with-nvm/.nvmrc"))
 			Expect(result).To(Equal("6.8.0"))
 		})
 	})