Fall back to link title for default page sort

Fixes #1299

hugolib/pageSort_test.go

@@ -5,10 +5,37 @@ import (
 	"github.com/stretchr/testify/assert"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/spf13/hugo/source"
 )
 
+func TesDefaultSort(t *testing.T) {
+
+	d1 := time.Now()
+	d2 := d1.Add(1 * time.Hour)
+	d3 := d1.Add(2 * time.Hour)
+
+	p := createSortTestPages(3)
+
+	// first by weight
+	setSortVals([3]time.Time{d1, d2, d3}, [3]string{"a", "b", "c"}, [3]int{3, 2, 1}, p)
+	p.Sort()
+	assert.Equal(t, 1, p[0].Weight)
+
+	// next by date
+	setSortVals([3]time.Time{d3, d1, d2}, [3]string{"a", "b", "c"}, [3]int{1, 1, 1}, p)
+	p.Sort()
+	assert.Equal(t, d1, p[0].Date)
+
+	// finally by title
+	setSortVals([3]time.Time{d3, d3, d3}, [3]string{"b", "a", "c"}, [3]int{1, 1, 1}, p)
+	p.Sort()
+	assert.Equal(t, "a", p[0].Title)
+	assert.Equal(t, "b", p[1].Title)
+	assert.Equal(t, "c", p[2].Title)
+}
+
 func TestPageSortReverse(t *testing.T) {
 	p1 := createSortTestPages(10)
 	assert.Equal(t, 0, p1[0].FuzzyWordCount)
@@ -28,6 +55,14 @@ func BenchmarkSortByWeightAndReverse(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		p = p.ByWeight().Reverse()
 	}
+}
+
+func setSortVals(dates [3]time.Time, titles [3]string, weights [3]int, pages Pages) {
+	for i := range dates {
+		pages[i].Date = dates[i]
+		pages[i].Weight = weights[i]
+		pages[i].Title = titles[i]
+	}
 
 }