Fix for #1021:

1. Make Usage field in completions Response to pointer.
2. Add omitempty to json tag

Signed-off-by: Hritik003 <[email protected]>

Author: Hritik003

completion.go

@@ -242,7 +242,7 @@ type CompletionResponse struct {
 	Created int64              `json:"created"`
 	Model   string             `json:"model"`
 	Choices []CompletionChoice `json:"choices"`
-	Usage   *Usage             `json:"usage"`
+	Usage   *Usage             `json:"usage,omitempty"`
 
 	httpHeader
 }

internal/error_accumulator_test.go

@@ -1,41 +1,32 @@
 package openai_test
 
 import (
-	"bytes"
-	"errors"
 	"testing"
 
-	utils "github.com/sashabaranov/go-openai/internal"
-	"github.com/sashabaranov/go-openai/internal/test"
+	openai "github.com/sashabaranov/go-openai/internal"
+	"github.com/sashabaranov/go-openai/internal/test/checks"
 )
 
-func TestErrorAccumulatorBytes(t *testing.T) {
-	accumulator := &utils.DefaultErrorAccumulator{
-		Buffer: &bytes.Buffer{},
+func TestDefaultErrorAccumulator_WriteMultiple(t *testing.T) {
+	ea, ok := openai.NewErrorAccumulator().(*openai.DefaultErrorAccumulator)
+	if !ok {
+		t.Fatal("type assertion to *DefaultErrorAccumulator failed")
 	}
+	checks.NoError(t, ea.Write([]byte("{\"error\": \"test1\"}")))
+	checks.NoError(t, ea.Write([]byte("{\"error\": \"test2\"}")))
 
-	errBytes := accumulator.Bytes()
-	if len(errBytes) != 0 {
-		t.Fatalf("Did not return nil with empty bytes: %s", string(errBytes))
-	}
-
-	err := accumulator.Write([]byte("{}"))
-	if err != nil {
-		t.Fatalf("%+v", err)
-	}
-
-	errBytes = accumulator.Bytes()
-	if len(errBytes) == 0 {
-		t.Fatalf("Did not return error bytes when has error: %s", string(errBytes))
+	expected := "{\"error\": \"test1\"}{\"error\": \"test2\"}"
+	if string(ea.Bytes()) != expected {
+		t.Fatalf("Expected %q, got %q", expected, ea.Bytes())
 	}
 }
 
-func TestErrorByteWriteErrors(t *testing.T) {
-	accumulator := &utils.DefaultErrorAccumulator{
-		Buffer: &test.FailingErrorBuffer{},
+func TestDefaultErrorAccumulator_EmptyBuffer(t *testing.T) {
+	ea, ok := openai.NewErrorAccumulator().(*openai.DefaultErrorAccumulator)
+	if !ok {
+		t.Fatal("type assertion to *DefaultErrorAccumulator failed")
 	}
-	err := accumulator.Write([]byte("{"))
-	if !errors.Is(err, test.ErrTestErrorAccumulatorWriteFailed) {
-		t.Fatalf("Did not return error when write failed: %v", err)
+	if len(ea.Bytes()) != 0 {
+		t.Fatal("Buffer should be empty initially")
 	}
 }

internal/form_builder.go

@@ -97,6 +97,9 @@ func (fb *DefaultFormBuilder) createFormFile(fieldname string, r io.Reader, file
 }
 
 func (fb *DefaultFormBuilder) WriteField(fieldname, value string) error {
+	if fieldname == "" {
+		return fmt.Errorf("fieldname cannot be empty")
+	}
 	return fb.writer.WriteField(fieldname, value)
 }
 

internal/form_builder_test.go

@@ -1,16 +1,57 @@
 package openai //nolint:testpackage // testing private field
 
 import (
+	"errors"
 	"io"
 
 	"github.com/sashabaranov/go-openai/internal/test/checks"
 
 	"bytes"
-	"errors"
 	"os"
 	"testing"
 )
 
+type mockFormBuilder struct {
+	mockCreateFormFile func(string, *os.File) error
+	mockWriteField     func(string, string) error
+	mockClose          func() error
+}
+
+func (m *mockFormBuilder) CreateFormFile(fieldname string, file *os.File) error {
+	return m.mockCreateFormFile(fieldname, file)
+}
+
+func (m *mockFormBuilder) WriteField(fieldname, value string) error {
+	return m.mockWriteField(fieldname, value)
+}
+
+func (m *mockFormBuilder) Close() error {
+	return m.mockClose()
+}
+
+func (m *mockFormBuilder) FormDataContentType() string {
+	return ""
+}
+
+func TestCloseMethod(t *testing.T) {
+	t.Run("NormalClose", func(t *testing.T) {
+		body := &bytes.Buffer{}
+		builder := NewFormBuilder(body)
+		checks.NoError(t, builder.Close(), "正常关闭应成功")
+	})
+
+	t.Run("ErrorPropagation", func(t *testing.T) {
+		errorMock := errors.New("mock close error")
+		mockBuilder := &mockFormBuilder{
+			mockClose: func() error {
+				return errorMock
+			},
+		}
+		err := mockBuilder.Close()
+		checks.ErrorIs(t, err, errorMock, "应传递关闭错误")
+	})
+}
+
 type failingWriter struct {
 }
 
@@ -90,3 +131,33 @@ func TestFormBuilderWithReader(t *testing.T) {
 	err = builder.CreateFormFileReader("file", rnc, "")
 	checks.NoError(t, err, "formbuilder should not return error")
 }
+
+func TestFormDataContentType(t *testing.T) {
+	t.Run("ReturnsUnderlyingWriterContentType", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		builder := NewFormBuilder(buf)
+
+		contentType := builder.FormDataContentType()
+		if contentType == "" {
+			t.Errorf("expected non-empty content type, got empty string")
+		}
+	})
+}
+
+func TestWriteField(t *testing.T) {
+	t.Run("EmptyFieldNameShouldReturnError", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		builder := NewFormBuilder(buf)
+
+		err := builder.WriteField("", "some value")
+		checks.HasError(t, err, "fieldname is required")
+	})
+
+	t.Run("ValidFieldNameShouldSucceed", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		builder := NewFormBuilder(buf)
+
+		err := builder.WriteField("key", "value")
+		checks.NoError(t, err, "should write field without error")
+	})
+}

internal/marshaller_test.go

@@ -0,0 +1,34 @@
+package openai_test
+
+import (
+	"testing"
+
+	openai "github.com/sashabaranov/go-openai/internal"
+	"github.com/sashabaranov/go-openai/internal/test/checks"
+)
+
+func TestJSONMarshaller_Normal(t *testing.T) {
+	jm := &openai.JSONMarshaller{}
+	data := map[string]string{"key": "value"}
+
+	b, err := jm.Marshal(data)
+	checks.NoError(t, err)
+	if len(b) == 0 {
+		t.Fatal("should return non-empty bytes")
+	}
+}
+
+func TestJSONMarshaller_InvalidInput(t *testing.T) {
+	jm := &openai.JSONMarshaller{}
+	_, err := jm.Marshal(make(chan int))
+	checks.HasError(t, err, "should return error for unsupported type")
+}
+
+func TestJSONMarshaller_EmptyValue(t *testing.T) {
+	jm := &openai.JSONMarshaller{}
+	b, err := jm.Marshal(nil)
+	checks.NoError(t, err)
+	if string(b) != "null" {
+		t.Fatalf("unexpected marshaled value: %s", string(b))
+	}
+}

internal/unmarshaler_test.go

@@ -0,0 +1,37 @@
+package openai_test
+
+import (
+	"testing"
+
+	openai "github.com/sashabaranov/go-openai/internal"
+	"github.com/sashabaranov/go-openai/internal/test/checks"
+)
+
+func TestJSONUnmarshaler_Normal(t *testing.T) {
+	jm := &openai.JSONUnmarshaler{}
+	data := []byte(`{"key":"value"}`)
+	var v map[string]string
+
+	err := jm.Unmarshal(data, &v)
+	checks.NoError(t, err)
+	if v["key"] != "value" {
+		t.Fatal("unmarshal result mismatch")
+	}
+}
+
+func TestJSONUnmarshaler_InvalidJSON(t *testing.T) {
+	jm := &openai.JSONUnmarshaler{}
+	data := []byte(`{invalid}`)
+	var v map[string]interface{}
+
+	err := jm.Unmarshal(data, &v)
+	checks.HasError(t, err, "should return error for invalid JSON")
+}
+
+func TestJSONUnmarshaler_EmptyInput(t *testing.T) {
+	jm := &openai.JSONUnmarshaler{}
+	var v interface{}
+
+	err := jm.Unmarshal(nil, &v)
+	checks.HasError(t, err, "should return error for nil input")
+}