Fix bugs for test pass, update tests

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

cmd/kubectx/kubeconfig.go

@@ -43,6 +43,9 @@ func parseKubeconfig(path string) (kubeconfig, error) {
 
 	f, err := os.Open(path)
 	if err != nil {
+		if os.IsNotExist(err) {
+			return v, nil
+		}
 		return v, errors.Wrap(err, "file open error")
 	}
 	err = yaml.NewDecoder(f).Decode(&v)

cmd/kubectx/main.go

@@ -38,7 +38,7 @@ func main() {
 			os.Exit(1)
 		}
 	case RenameOp:
-		if err := rename(v.Old, v.New); err != nil {
+		if err := renameContexts(v.Old, v.New); err != nil {
 			printError("failed to rename: %v", err)
 			os.Exit(1)
 		}

cmd/kubectx/rename.go

@@ -26,7 +26,7 @@ func parseRenameSyntax(v string) (string, string, bool) {
 // rename changes the old (NAME or '.' for current-context)
 // to the "new" value. If the old refers to the current-context,
 // current-context preference is also updated.
-func rename(old, new string) error {
+func renameContexts(old, new string) error {
 	f, rootNode, err := openKubeconfig()
 	if err != nil {
 		return nil

test/kubectx.bats

@@ -4,16 +4,6 @@ COMMAND="$BATS_TEST_DIRNAME/../kubectx"
 
 load common
 
-@test "no kubectl detected" {
-  OLDPATH="$PATH"
-  PATH=/bin
-  run ${COMMAND}
-  echo "$output"
-  [ "$status" -eq 1 ]
-  [[ "$output" = "kubectl is not installed" ]]
-  PATH="$OLDPATH"
-}
-
 @test "--help should not fail" {
   run ${COMMAND} --help
   echo "$output"
@@ -32,7 +22,7 @@ load common
   run ${COMMAND} -
   echo "$output"
   [ "$status" -eq 1 ]
-  [[ "$output" = "error: No previous context found." ]]
+  [[ $output = *"no previous context found" ]]
 }
 
 @test "list contexts when no kubeconfig exists" {