1 files changed, 135 insertions, 0 deletions
diff --git a/pkg/utils/slice_test.go b/pkg/utils/slice_test.go
new file mode 100644
index 000000000..858b1b904
--- /dev/null
+++ b/pkg/utils/slice_test.go
@@ -0,0 +1,135 @@
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestIncludesString is a function.
+func TestIncludesString(t *testing.T) {
+	type scenario struct {
+		list     []string
+		element  string
+		expected bool
+	}
+
+	scenarios := []scenario{
+		{
+			[]string{"a", "b"},
+			"a",
+			true,
+		},
+		{
+			[]string{"a", "b"},
+			"c",
+			false,
+		},
+		{
+			[]string{"a", "b"},
+			"",
+			false,
+		},
+		{
+			[]string{""},
+			"",
+			true,
+		},
+	}
+
+	for _, s := range scenarios {
+		assert.EqualValues(t, s.expected, IncludesString(s.list, s.element))
+	}
+}
+
+func TestNextIndex(t *testing.T) {
+	type scenario struct {
+		testName string
+		list     []int
+		element  int
+		expected int
+	}
+
+	scenarios := []scenario{
+		{
+			// I'm not really fussed about how it behaves here
+			"no elements",
+			[]int{},
+			1,
+			-1,
+		},
+		{
+			"one element",
+			[]int{1},
+			1,
+			0,
+		},
+		{
+			"two elements",
+			[]int{1, 2},
+			1,
+			1,
+		},
+		{
+			"two elements, giving second one",
+			[]int{1, 2},
+			2,
+			1,
+		},
+		{
+			"three elements, giving second one",
+			[]int{1, 2, 3},
+			2,
+			2,
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			assert.EqualValues(t, s.expected, NextIndex(s.list, s.element))
+		})
+	}
+}
+
+func TestPrevIndex(t *testing.T) {
+	type scenario struct {
+		testName string
+		list     []int
+		element  int
+		expected int
+	}
+
+	scenarios := []scenario{
+		{
+			// I'm not really fussed about how it behaves here
+			"no elements",
+			[]int{},
+			1,
+			0,
+		},
+		{
+			"one element",
+			[]int{1},
+			1,
+			0,
+		},
+		{
+			"two elements",
+			[]int{1, 2},
+			1,
+			0,
+		},
+		{
+			"three elements, giving second one",
+			[]int{1, 2, 3},
+			2,
+			0,
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			assert.EqualValues(t, s.expected, PrevIndex(s.list, s.element))
+		})
+	}
+}