moving checks to their relevant stops so unit tests work

cmd/extract/extract.go

@@ -24,6 +24,9 @@ Usage: from the root minikube directory, go run cmd/extract/extract.go
 package main
 
 import (
+	"os"
+	"strings"
+
 	"k8s.io/minikube/pkg/minikube/extract"
 )
 
@@ -31,7 +34,19 @@ func main() {
 	paths := []string{"cmd", "pkg"}
 	functions := []string{"translate.T"}
 	outDir := "translations"
-	err := extract.TranslatableStrings(paths, functions, outDir)
+	cwd, err := os.Getwd()
+	if err != nil {
+		panic("Getting current working directory failed")
+	}
+
+	if strings.Contains(cwd, "cmd") {
+		panic("run extract.go from the minikube root directory")
+	}
+
+	if _, err = os.Stat(extract.ErrMapFile); os.IsNotExist(err) {
+		panic("err_map.go doesn't exist")
+	}
+	err = extract.TranslatableStrings(paths, functions, outDir)
 
 	if err != nil {
 		panic(err)

pkg/minikube/extract/extract.go

@@ -47,7 +47,7 @@ var blacklist = []string{
 	"opt %s",
 }
 
-const errMapFile string = "pkg/minikube/problem/err_map.go"
+const ErrMapFile string = "pkg/minikube/problem/err_map.go"
 
 // state is a struct that represent the current state of the extraction process
 type state struct {
@@ -114,19 +114,6 @@ func setParentFunc(e *state, f string) {
 
 // TranslatableStrings finds all strings to that need to be translated in paths and prints them out to all json files in output
 func TranslatableStrings(paths []string, functions []string, output string) error {
-	cwd, err := os.Getwd()
-	if err != nil {
-		return errors.Wrap(err, "Getting current working directory")
-	}
-
-	if strings.Contains(cwd, "cmd") {
-		return errors.New("run extract.go from the minikube root directory")
-	}
-
-	if _, err = os.Stat(errMapFile); os.IsNotExist(err) {
-		return errors.New("err_map.go doesn't exist")
-	}
-
 	e, err := newExtractor(functions)
 
 	if err != nil {
@@ -178,7 +165,7 @@ func inspectFile(e *state) error {
 		return err
 	}
 
-	if e.filename == errMapFile {
+	if e.filename == ErrMapFile {
 		return extractAdvice(file, e)
 	}