[FAB-3485] improve test coverage for msp

Test output for msp now is

coverage: 86.1% of statements
ok		github.com/hyperledger/fabric/msp	0.054s

Change-Id: Ic6fb239df31074224bd150d24305cb098dcc13d8
Signed-off-by: Alessandro Sorniotti <ale.linux@sopit.net>

msp/configbuilder_test.go

@@ -0,0 +1,46 @@
+/*
+Copyright IBM Corp. 2017 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+		 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package msp
+
+import (
+	"testing"
+
+	"github.com/hyperledger/fabric/core/config"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetLocalMspConfig(t *testing.T) {
+	mspDir, err := config.GetDevMspDir()
+	assert.NoError(t, err)
+	_, err = GetLocalMspConfig(mspDir, nil, "DEFAULT")
+	assert.NoError(t, err)
+}
+
+func TestGetLocalMspConfigFails(t *testing.T) {
+	_, err := GetLocalMspConfig("/tmp/", nil, "DEFAULT")
+	assert.Error(t, err)
+}
+
+func TestReadFileUtils(t *testing.T) {
+	// test that reading a file with an empty path doesn't crash
+	_, err := readPemFile("")
+	assert.Error(t, err)
+
+	// test that reading an existing file which is not a PEM file doesn't crash
+	_, err = readPemFile("/dev/null")
+	assert.Error(t, err)
+}

msp/identities.go

@@ -144,12 +144,12 @@ func (id *identity) Verify(msg []byte, sig []byte) error {
 
 func (id *identity) VerifyOpts(msg []byte, sig []byte, opts SignatureOpts) error {
 	// TODO
-	return nil
+	return errors.New("This method is unimplemented")
 }
 
 func (id *identity) VerifyAttributes(proof []byte, spec *AttributeProofSpec) error {
 	// TODO
-	return nil
+	return errors.New("This method is unimplemented")
 }
 
 // Serialize returns a byte array representation of this identity
@@ -225,12 +225,12 @@ func (id *signingidentity) Sign(msg []byte) ([]byte, error) {
 
 func (id *signingidentity) SignOpts(msg []byte, opts SignatureOpts) ([]byte, error) {
 	// TODO
-	return nil, nil
+	return nil, errors.New("This method is unimplemented")
 }
 
 func (id *signingidentity) GetAttributeProof(spec *AttributeProofSpec) (proof []byte, err error) {
 	// TODO
-	return nil, nil
+	return nil, errors.New("This method is unimplemented")
 }
 
 func (id *signingidentity) GetPublicVersion() Identity {
@@ -239,5 +239,5 @@ func (id *signingidentity) GetPublicVersion() Identity {
 
 func (id *signingidentity) Renew() error {
 	// TODO
-	return nil
+	return errors.New("This method is unimplemented")
 }