Fix GroupBy function issues

Following issues are fixed

1. Can't access fields and methods specified in GroupBy call
2. PagesGroup doesn't contain Pages. It's always empty.
3. When GroupBy is called with Section key, it doesn't work as expected

hugolib/pageGroup.go

@@ -79,9 +79,6 @@ var (
 )
 
 func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
-
-	key = strings.ToLower(key)
-
 	if len(p) < 1 {
 		return nil, nil
 	}
@@ -93,12 +90,8 @@ func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
 	}
 
 	var ft interface{}
-	ft, ok := pagePtrType.Elem().FieldByName(key)
+	m, ok := pagePtrType.MethodByName(key)
-	if !ok {
+	if ok {
-		m, ok := pagePtrType.MethodByName(key)
-		if !ok {
-			return nil, errors.New(key + " is neither a field nor a method of Page")
-		}
 		if m.Type.NumIn() != 1 || m.Type.NumOut() == 0 || m.Type.NumOut() > 2 {
 			return nil, errors.New(key + " is a Page method but you can't use it with GroupBy")
 		}
@@ -109,6 +102,11 @@ func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
 			return nil, errors.New(key + " is a Page method but you can't use it with GroupBy")
 		}
 		ft = m
+	} else {
+		ft, ok = pagePtrType.Elem().FieldByName(key)
+		if !ok {
+			return nil, errors.New(key + " is neither a field nor a method of Page")
+		}
 	}
 
 	var tmp reflect.Value
@@ -134,6 +132,7 @@ func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
 		if !tmp.MapIndex(fv).IsValid() {
 			tmp.SetMapIndex(fv, reflect.MakeSlice(reflect.SliceOf(pagePtrType), 0, 0))
 		}
+		tmp.SetMapIndex(fv, reflect.Append(tmp.MapIndex(fv), ppv))
 	}
 
 	var r []PageGroup

hugolib/pageGroup_test.go

@@ -0,0 +1,382 @@
+package hugolib
+
+import (
+	"errors"
+	"reflect"
+	"testing"
+
+	"github.com/spf13/cast"
+)
+
+type pageGroupTestObject struct {
+	path   string
+	weight int
+	date   string
+	param  string
+}
+
+var pageGroupTestSources = []pageGroupTestObject{
+	{"/section1/testpage1.md", 3, "2012-04-06", "foo"},
+	{"/section1/testpage2.md", 3, "2012-01-01", "bar"},
+	{"/section1/testpage3.md", 2, "2012-04-06", "foo"},
+	{"/section2/testpage4.md", 1, "2012-03-02", "bar"},
+	{"/section2/testpage5.md", 1, "2012-04-06", "baz"},
+}
+
+func preparePageGroupTestPages(t *testing.T) Pages {
+	var pages Pages
+	for _, s := range pageGroupTestSources {
+		p, err := NewPage(s.path)
+		if err != nil {
+			t.Fatalf("failed to prepare test page %s", s.path)
+		}
+		p.Weight = s.weight
+		p.Date = cast.ToTime(s.date)
+		p.PublishDate = cast.ToTime(s.date)
+		p.Params["custom_param"] = s.param
+		p.Params["custom_date"] = cast.ToTime(s.date)
+		pages = append(pages, p)
+	}
+	return pages
+}
+
+func TestGroupByWithFieldNameArg(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: 1, Pages: Pages{pages[3], pages[4]}},
+		{Key: 2, Pages: Pages{pages[2]}},
+		{Key: 3, Pages: Pages{pages[0], pages[1]}},
+	}
+
+	groups, err := pages.GroupBy("Weight")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByWithMethodNameArg(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "section1", Pages: Pages{pages[0], pages[1], pages[2]}},
+		{Key: "section2", Pages: Pages{pages[3], pages[4]}},
+	}
+
+	groups, err := pages.GroupBy("Type")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByWithSectionArg(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "section1", Pages: Pages{pages[0], pages[1], pages[2]}},
+		{Key: "section2", Pages: Pages{pages[3], pages[4]}},
+	}
+
+	groups, err := pages.GroupBy("Section")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByInReverseOrder(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: 3, Pages: Pages{pages[0], pages[1]}},
+		{Key: 2, Pages: Pages{pages[2]}},
+		{Key: 1, Pages: Pages{pages[3], pages[4]}},
+	}
+
+	groups, err := pages.GroupBy("Weight", "desc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByCalledWithEmptyPages(t *testing.T) {
+	var pages Pages
+	groups, err := pages.GroupBy("Weight")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if groups != nil {
+		t.Errorf("PagesGroup isn't empty. It should be %#v, got %#v", nil, groups)
+	}
+}
+
+func TestGroupByCalledWithUnavailableKey(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	_, err := pages.GroupBy("UnavailableKey")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+}
+
+func (page *Page) dummyPageMethodWithArgForTest(s string) string {
+	return s
+}
+
+func (page *Page) dummyPageMethodReturnThreeValueForTest() (string, string, string) {
+	return "foo", "bar", "baz"
+}
+
+func (page *Page) dummyPageMethodReturnErrorOnlyForTest() error {
+	return errors.New("something error occured")
+}
+
+func (page *Page) dummyPageMethodReturnTwoValueForTest() (string, string) {
+	return "foo", "bar"
+}
+
+func TestGroupByCalledWithInvalidMethod(t *testing.T) {
+	var err error
+	pages := preparePageGroupTestPages(t)
+
+	_, err = pages.GroupBy("dummyPageMethodWithArgForTest")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+
+	_, err = pages.GroupBy("dummyPageMethodReturnThreeValueForTest")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+
+	_, err = pages.GroupBy("dummyPageMethodReturnErrorOnlyForTest")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+
+	_, err = pages.GroupBy("dummyPageMethodReturnTwoValueForTest")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+}
+
+func TestReverse(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+
+	groups1, err := pages.GroupBy("Weight", "desc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+
+	groups2, err := pages.GroupBy("Weight")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	groups2 = groups2.Reverse()
+
+	if !reflect.DeepEqual(groups2, groups1) {
+		t.Errorf("PagesGroup is sorted in unexpected order. It should be %#v, got %#v", groups2, groups1)
+	}
+}
+
+func TestGroupByParam(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "bar", Pages: Pages{pages[1], pages[3]}},
+		{Key: "baz", Pages: Pages{pages[4]}},
+		{Key: "foo", Pages: Pages{pages[0], pages[2]}},
+	}
+
+	groups, err := pages.GroupByParam("custom_param")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByParamInReverseOrder(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "foo", Pages: Pages{pages[0], pages[2]}},
+		{Key: "baz", Pages: Pages{pages[4]}},
+		{Key: "bar", Pages: Pages{pages[1], pages[3]}},
+	}
+
+	groups, err := pages.GroupByParam("custom_param", "desc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByParamCalledWithSomeUnavailableParams(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	delete(pages[1].Params, "custom_param")
+	delete(pages[3].Params, "custom_param")
+	delete(pages[4].Params, "custom_param")
+
+	expect := PagesGroup{
+		{Key: "foo", Pages: Pages{pages[0], pages[2]}},
+	}
+
+	groups, err := pages.GroupByParam("custom_param")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByParamCalledWithEmptyPages(t *testing.T) {
+	var pages Pages
+	groups, err := pages.GroupByParam("custom_param")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if groups != nil {
+		t.Errorf("PagesGroup isn't empty. It should be %#v, got %#v", nil, groups)
+	}
+}
+
+func TestGroupByParamCalledWithUnavailableParam(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	_, err := pages.GroupByParam("unavailable_param")
+	if err == nil {
+		t.Errorf("GroupByParam should return an error but didn't")
+	}
+}
+
+func TestGroupByDate(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-04", Pages: Pages{pages[4], pages[2], pages[0]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+	}
+
+	groups, err := pages.GroupByDate("2006-01")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByDateInReverseOrder(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-04", Pages: Pages{pages[0], pages[2], pages[4]}},
+	}
+
+	groups, err := pages.GroupByDate("2006-01", "asc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByPublishDate(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-04", Pages: Pages{pages[4], pages[2], pages[0]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+	}
+
+	groups, err := pages.GroupByPublishDate("2006-01")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByPublishDateInReverseOrder(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-04", Pages: Pages{pages[0], pages[2], pages[4]}},
+	}
+
+	groups, err := pages.GroupByDate("2006-01", "asc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByPublishDateWithEmptyPages(t *testing.T) {
+	var pages Pages
+	groups, err := pages.GroupByPublishDate("2006-01")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if groups != nil {
+		t.Errorf("PagesGroup isn't empty. It should be %#v, got %#v", nil, groups)
+	}
+}
+
+func TestGroupByParamDate(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-04", Pages: Pages{pages[4], pages[2], pages[0]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+	}
+
+	groups, err := pages.GroupByParamDate("custom_date", "2006-01")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByParamDateInReverseOrder(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	expect := PagesGroup{
+		{Key: "2012-01", Pages: Pages{pages[1]}},
+		{Key: "2012-03", Pages: Pages{pages[3]}},
+		{Key: "2012-04", Pages: Pages{pages[0], pages[2], pages[4]}},
+	}
+
+	groups, err := pages.GroupByParamDate("custom_date", "2006-01", "asc")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if !reflect.DeepEqual(groups, expect) {
+		t.Errorf("PagesGroup has unexpected groups. It should be %#v, got %#v", expect, groups)
+	}
+}
+
+func TestGroupByParamDateWithEmptyPages(t *testing.T) {
+	var pages Pages
+	groups, err := pages.GroupByParamDate("custom_date", "2006-01")
+	if err != nil {
+		t.Fatalf("Unable to make PagesGroup array: %s", err)
+	}
+	if groups != nil {
+		t.Errorf("PagesGroup isn't empty. It should be %#v, got %#v", nil, groups)
+	}
+}