feat(collections): IndexedMap (#14397)

Co-authored-by: testinginprod <testinginprod@somewhere.idk>
Co-authored-by: Marko <marbar3778@yahoo.com>
Co-authored-by: Likhita Polavarapu <78951027+likhita-809@users.noreply.github.com>

collections/colltest/codec_test.go

@@ -0,0 +1,48 @@
+package colltest
+
+import "testing"
+
+type animal interface {
+	name() string
+}
+
+type dog struct {
+	Name        string `json:"name"`
+	BarksLoudly bool   `json:"barks_loudly"`
+}
+
+type cat struct {
+	Name      string `json:"name"`
+	Scratches bool   `json:"scratches"`
+}
+
+func (d *cat) name() string { return d.Name }
+
+func (d dog) name() string { return d.Name }
+
+func TestMockValueCodec(t *testing.T) {
+	t.Run("primitive type", func(t *testing.T) {
+		x := MockValueCodec[string]()
+		TestValueCodec(t, x, "hello")
+	})
+
+	t.Run("struct type", func(t *testing.T) {
+		x := MockValueCodec[dog]()
+		TestValueCodec(t, x, dog{
+			Name:        "kernel",
+			BarksLoudly: true,
+		})
+	})
+
+	t.Run("interface type", func(t *testing.T) {
+		x := MockValueCodec[animal]()
+		TestValueCodec[animal](t, x, dog{
+			Name:        "kernel",
+			BarksLoudly: true,
+		})
+		TestValueCodec[animal](t, x, &cat{
+			Name:      "echo",
+			Scratches: true,
+		})
+	})
+}