move request_builder into internal pkg (#304) (#329)

* move request_builder into internal pkg (#304)

* add some test for internal.RequestBuilder

* add a test for openai.GetEngine

internal/request_builder_test.go

@@ -0,0 +1,61 @@
+package openai //nolint:testpackage // testing private field
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"net/http"
+	"reflect"
+	"testing"
+)
+
+var errTestMarshallerFailed = errors.New("test marshaller failed")
+
+type failingMarshaller struct{}
+
+func (*failingMarshaller) Marshal(_ any) ([]byte, error) {
+	return []byte{}, errTestMarshallerFailed
+}
+
+func TestRequestBuilderReturnsMarshallerErrors(t *testing.T) {
+	builder := HTTPRequestBuilder{
+		marshaller: &failingMarshaller{},
+	}
+
+	_, err := builder.Build(context.Background(), "", "", struct{}{})
+	if !errors.Is(err, errTestMarshallerFailed) {
+		t.Fatalf("Did not return error when marshaller failed: %v", err)
+	}
+}
+
+func TestRequestBuilderReturnsRequest(t *testing.T) {
+	b := NewRequestBuilder()
+	var (
+		ctx         = context.Background()
+		method      = http.MethodPost
+		url         = "/foo"
+		request     = map[string]string{"foo": "bar"}
+		reqBytes, _ = b.marshaller.Marshal(request)
+		want, _     = http.NewRequestWithContext(ctx, method, url, bytes.NewBuffer(reqBytes))
+	)
+	got, _ := b.Build(ctx, method, url, request)
+	if !reflect.DeepEqual(got.Body, want.Body) ||
+		!reflect.DeepEqual(got.URL, want.URL) ||
+		!reflect.DeepEqual(got.Method, want.Method) {
+		t.Errorf("Build() got = %v, want %v", got, want)
+	}
+}
+
+func TestRequestBuilderReturnsRequestWhenRequestOfArgsIsNil(t *testing.T) {
+	var (
+		ctx     = context.Background()
+		method  = http.MethodGet
+		url     = "/foo"
+		want, _ = http.NewRequestWithContext(ctx, method, url, nil)
+	)
+	b := NewRequestBuilder()
+	got, _ := b.Build(ctx, method, url, nil)
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Build() got = %v, want %v", got, want)
+	}
+}