diff --git a/arduino/libraries/libraries_layout.go b/arduino/libraries/libraries_layout.go
index 2a85f95d5ce..8391141322a 100644
--- a/arduino/libraries/libraries_layout.go
+++ b/arduino/libraries/libraries_layout.go
@@ -38,19 +38,14 @@ func (d *LibraryLayout) String() string {
 		return "flat"
 	case RecursiveLayout:
 		return "recursive"
+	default:
+		panic(fmt.Sprintf("invalid LibraryLayout value %d", *d))
 	}
-	panic(fmt.Sprintf("invalid LibraryLayout value %d", *d))
 }
 
 // MarshalJSON implements the json.Marshaler interface
-func (d *LibraryLayout) MarshalJSON() ([]byte, error) {
-	switch *d {
-	case FlatLayout:
-		return json.Marshal("flat")
-	case RecursiveLayout:
-		return json.Marshal("recursive")
-	}
-	return nil, fmt.Errorf(tr("invalid library layout value: %d"), *d)
+func (d LibraryLayout) MarshalJSON() ([]byte, error) {
+	return json.Marshal(d.String())
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface
@@ -62,10 +57,13 @@ func (d *LibraryLayout) UnmarshalJSON(b []byte) error {
 	switch s {
 	case "flat":
 		*d = FlatLayout
+		return nil
 	case "recursive":
 		*d = RecursiveLayout
+		return nil
+	default:
+		return fmt.Errorf(tr("invalid library layout: %s"), s)
 	}
-	return fmt.Errorf(tr("invalid library layout: %s"), s)
 }
 
 // ToRPCLibraryLayout converts this LibraryLayout to rpc.LibraryLayout
@@ -75,6 +73,7 @@ func (d *LibraryLayout) ToRPCLibraryLayout() rpc.LibraryLayout {
 		return rpc.LibraryLayout_LIBRARY_LAYOUT_FLAT
 	case RecursiveLayout:
 		return rpc.LibraryLayout_LIBRARY_LAYOUT_RECURSIVE
+	default:
+		panic(fmt.Sprintf("invalid LibraryLayout value %d", *d))
 	}
-	panic(fmt.Sprintf("invalid LibraryLayout value %d", *d))
 }
diff --git a/arduino/libraries/libraries_location.go b/arduino/libraries/libraries_location.go
index e6bd933ebd6..f93a6a01f40 100644
--- a/arduino/libraries/libraries_location.go
+++ b/arduino/libraries/libraries_location.go
@@ -52,25 +52,14 @@ func (d *LibraryLocation) String() string {
 		return "user"
 	case Unmanaged:
 		return "unmanaged"
+	default:
+		panic(fmt.Sprintf("invalid LibraryLocation value %d", *d))
 	}
-	panic(fmt.Sprintf("invalid LibraryLocation value %d", *d))
 }
 
 // MarshalJSON implements the json.Marshaler interface
-func (d *LibraryLocation) MarshalJSON() ([]byte, error) {
-	switch *d {
-	case IDEBuiltIn:
-		return json.Marshal("ide")
-	case PlatformBuiltIn:
-		return json.Marshal("platform")
-	case ReferencedPlatformBuiltIn:
-		return json.Marshal("ref-platform")
-	case User:
-		return json.Marshal("user")
-	case Unmanaged:
-		return json.Marshal("unmanaged")
-	}
-	return nil, fmt.Errorf(tr("invalid library location value: %d"), *d)
+func (d LibraryLocation) MarshalJSON() ([]byte, error) {
+	return json.Marshal(d.String())
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface
@@ -82,16 +71,22 @@ func (d *LibraryLocation) UnmarshalJSON(b []byte) error {
 	switch s {
 	case "ide":
 		*d = IDEBuiltIn
+		return nil
 	case "platform":
 		*d = PlatformBuiltIn
+		return nil
 	case "ref-platform":
 		*d = ReferencedPlatformBuiltIn
+		return nil
 	case "user":
 		*d = User
+		return nil
 	case "unmanaged":
 		*d = Unmanaged
+		return nil
+	default:
+		return fmt.Errorf(tr("invalid library location: %s"), s)
 	}
-	return fmt.Errorf(tr("invalid library location: %s"), s)
 }
 
 // ToRPCLibraryLocation converts this LibraryLocation to rpc.LibraryLocation
@@ -107,8 +102,9 @@ func (d *LibraryLocation) ToRPCLibraryLocation() rpc.LibraryLocation {
 		return rpc.LibraryLocation_LIBRARY_LOCATION_USER
 	case Unmanaged:
 		return rpc.LibraryLocation_LIBRARY_LOCATION_UNMANAGED
+	default:
+		panic(fmt.Sprintf("invalid LibraryLocation value %d", *d))
 	}
-	panic(fmt.Sprintf("invalid LibraryLocation value %d", *d))
 }
 
 // FromRPCLibraryLocation converts a rpc.LibraryLocation to a LibraryLocation
@@ -124,6 +120,7 @@ func FromRPCLibraryLocation(l rpc.LibraryLocation) LibraryLocation {
 		return User
 	case rpc.LibraryLocation_LIBRARY_LOCATION_UNMANAGED:
 		return Unmanaged
+	default:
+		panic(fmt.Sprintf("invalid rpc.LibraryLocation value %d", l))
 	}
-	panic(fmt.Sprintf("invalid rpc.LibraryLocation value %d", l))
 }
diff --git a/arduino/libraries/libraries_test.go b/arduino/libraries/libraries_test.go
new file mode 100644
index 00000000000..09461790f8a
--- /dev/null
+++ b/arduino/libraries/libraries_test.go
@@ -0,0 +1,50 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package libraries
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestLibLayoutAndLocationJSONUnMarshaler(t *testing.T) {
+	testLayout := func(l LibraryLayout) {
+		d, err := json.Marshal(l)
+		require.NoError(t, err)
+		var m LibraryLayout
+		err = json.Unmarshal(d, &m)
+		require.NoError(t, err)
+		require.Equal(t, l, m)
+	}
+	testLayout(FlatLayout)
+	testLayout(RecursiveLayout)
+
+	testLocation := func(l LibraryLocation) {
+		d, err := json.Marshal(l)
+		require.NoError(t, err)
+		var m LibraryLocation
+		err = json.Unmarshal(d, &m)
+		require.NoError(t, err)
+		require.Equal(t, l, m)
+	}
+	testLocation(IDEBuiltIn)
+	testLocation(PlatformBuiltIn)
+	testLocation(ReferencedPlatformBuiltIn)
+	testLocation(User)
+	testLocation(Unmanaged)
+}