Guarantees the AdditionalProperties map is not nil

Resolves #13

scim/resource.go

@@ -146,6 +146,10 @@ func (ca *CommonAttributes) HasExtensionByURN(urn string) bool {
 }
 
 func (ca *CommonAttributes) putExtension(extension Extension) error {
+	if ca.AdditionalProperties == nil {
+		ca.AdditionalProperties = make(map[string]json.RawMessage)
+	}
+
 	urn := extension.URN()
 	var err error
 	var rawMessage json.RawMessage

scim/resource_test.go

@@ -95,6 +95,16 @@ func TestAddExtension(t *testing.T) {
 	assert.Equal(json.RawMessage("{}"), value)
 }
 
+func TestAddAndUpdateExtensionWithEmptyResource(t *testing.T) {
+	var ca CommonAttributes
+	var fakeExtension fakeExtension
+	var worthlessExtension worthlessExtension
+	assert.NoError(t, ca.AddExtension(fakeExtension))
+	assert.NoError(t, ca.AddExtension(worthlessExtension))
+	assert.NoError(t, ca.UpdateExtension(&fakeExtension))
+	assert.NoError(t, ca.UpdateExtension(&worthlessExtension))
+}
+
 func TestGetExtension(t *testing.T) {
 	assert := assert.New(t)
 	resource := getResourceWithAdditionalProperties()
@@ -104,6 +114,14 @@ func TestGetExtension(t *testing.T) {
 	assert.Nil(err)
 }
 
+func TestGetExtensionWithEmptyResource(t *testing.T) {
+	var ca CommonAttributes
+	var fakeExtension fakeExtension
+	var worthlessExtension worthlessExtension
+	assert.Error(t, ca.GetExtension(&fakeExtension))
+	assert.Error(t, ca.GetExtension(&worthlessExtension))
+}
+
 func TestGetExtensionURNs(t *testing.T) {
 	assert := assert.New(t)
 	resource := getResourceWithAdditionalProperties()
@@ -129,6 +147,14 @@ func TestHasExtension(t *testing.T) {
 	assert.False(resource.HasExtension(worthlessExtension))
 }
 
+func TestHasExtensionWithEmptyResource(t *testing.T) {
+	var ca CommonAttributes
+	var fakeExtension fakeExtension
+	var worthlessExtension worthlessExtension
+	assert.False(t, ca.HasExtension((fakeExtension)))
+	assert.False(t, ca.HasExtension(worthlessExtension))
+}
+
 func TestRemoveExtension(t *testing.T) {
 	assert := assert.New(t)
 	require := require.New(t)