1 files changed, 124 insertions, 0 deletions
diff --git a/common/collections/slice_test.go b/common/collections/slice_test.go
new file mode 100644
index 000000000..3ebfe6d11
--- /dev/null
+++ b/common/collections/slice_test.go
@@ -0,0 +1,124 @@
+// Copyright 2019 The Hugo Authors. 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 collections
+
+import (
+	"errors"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+var _ Slicer = (*tstSlicer)(nil)
+var _ Slicer = (*tstSlicerIn1)(nil)
+var _ Slicer = (*tstSlicerIn2)(nil)
+var _ testSlicerInterface = (*tstSlicerIn1)(nil)
+var _ testSlicerInterface = (*tstSlicerIn1)(nil)
+
+type testSlicerInterface interface {
+	Name() string
+}
+
+type testSlicerInterfaces []testSlicerInterface
+
+type tstSlicerIn1 struct {
+	TheName string
+}
+
+type tstSlicerIn2 struct {
+	TheName string
+}
+
+type tstSlicer struct {
+	TheName string
+}
+
+func (p *tstSlicerIn1) Slice(in interface{}) (interface{}, error) {
+	items := in.([]interface{})
+	result := make(testSlicerInterfaces, len(items))
+	for i, v := range items {
+		switch vv := v.(type) {
+		case testSlicerInterface:
+			result[i] = vv
+		default:
+			return nil, errors.New("invalid type")
+		}
+
+	}
+	return result, nil
+}
+
+func (p *tstSlicerIn2) Slice(in interface{}) (interface{}, error) {
+	items := in.([]interface{})
+	result := make(testSlicerInterfaces, len(items))
+	for i, v := range items {
+		switch vv := v.(type) {
+		case testSlicerInterface:
+			result[i] = vv
+		default:
+			return nil, errors.New("invalid type")
+		}
+	}
+	return result, nil
+}
+
+func (p *tstSlicerIn1) Name() string {
+	return p.TheName
+}
+
+func (p *tstSlicerIn2) Name() string {
+	return p.TheName
+}
+
+func (p *tstSlicer) Slice(in interface{}) (interface{}, error) {
+	items := in.([]interface{})
+	result := make(tstSlicers, len(items))
+	for i, v := range items {
+		switch vv := v.(type) {
+		case *tstSlicer:
+			result[i] = vv
+		default:
+			return nil, errors.New("invalid type")
+		}
+	}
+	return result, nil
+}
+
+type tstSlicers []*tstSlicer
+
+func TestSlice(t *testing.T) {
+	t.Parallel()
+	c := qt.New(t)
+
+	for i, test := range []struct {
+		args     []interface{}
+		expected interface{}
+	}{
+		{[]interface{}{"a", "b"}, []string{"a", "b"}},
+		{[]interface{}{&tstSlicer{"a"}, &tstSlicer{"b"}}, tstSlicers{&tstSlicer{"a"}, &tstSlicer{"b"}}},
+		{[]interface{}{&tstSlicer{"a"}, "b"}, []interface{}{&tstSlicer{"a"}, "b"}},
+		{[]interface{}{}, []interface{}{}},
+		{[]interface{}{nil}, []interface{}{nil}},
+		{[]interface{}{5, "b"}, []interface{}{5, "b"}},
+		{[]interface{}{&tstSlicerIn1{"a"}, &tstSlicerIn2{"b"}}, testSlicerInterfaces{&tstSlicerIn1{"a"}, &tstSlicerIn2{"b"}}},
+		{[]interface{}{&tstSlicerIn1{"a"}, &tstSlicer{"b"}}, []interface{}{&tstSlicerIn1{"a"}, &tstSlicer{"b"}}},
+	} {
+		errMsg := qt.Commentf("[%d] %v", i, test.args)
+
+		result := Slice(test.args...)
+
+		c.Assert(test.expected, qt.DeepEquals, result, errMsg)
+	}
+
+}