make Get(Raw)AttributeValues compare case insensitive

This is the same way an LDAP server compares during a search request.

Fixes go-ldap#109

search.go

@@ -128,8 +128,9 @@ type Entry struct {
 
 // GetAttributeValues returns the values for the named attribute, or an empty list
 func (e *Entry) GetAttributeValues(attribute string) []string {
+	attribute = strings.ToLower(attribute)
 	for _, attr := range e.Attributes {
-		if attr.Name == attribute {
+		if strings.ToLower(attr.Name) == attribute {
 			return attr.Values
 		}
 	}
@@ -138,8 +139,9 @@ func (e *Entry) GetAttributeValues(attribute string) []string {
 
 // GetRawAttributeValues returns the byte values for the named attribute, or an empty list
 func (e *Entry) GetRawAttributeValues(attribute string) [][]byte {
+	attribute = strings.ToLower(attribute)
 	for _, attr := range e.Attributes {
-		if attr.Name == attribute {
+		if strings.ToLower(attr.Name) == attribute {
 			return attr.ByteValues
 		}
 	}

search_test.go

@@ -29,3 +29,21 @@ func TestNewEntry(t *testing.T) {
 		iteration = iteration + 1
 	}
 }
+
+func TestGetAttributeValue(t *testing.T) {
+	dn := "testDN"
+	attributes := map[string][]string{
+		"Alpha":   {"value"},
+		"bEta":    {"value"},
+		"gaMma":   {"value"},
+		"delTa":   {"value"},
+		"epsiLon": {"value"},
+	}
+	entry := NewEntry(dn, attributes)
+	if entry.GetAttributeValue("Alpha") != "value" {
+		t.Errorf("failed to get attribute in original case")
+	}
+	if entry.GetAttributeValue("alpha") != "value" {
+		t.Errorf("failed to get attribute in changed case")
+	}
+}