test: add gzip compression and decompression tests

- Add tests for gzip compression and decompression using the Gin framework
- Verify gzip content encoding and response body in tests
- Ensure correct handling of gzip and non-gzip requests
- Test decompression of gzip-encoded POST request data

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

handler_test.go

@@ -0,0 +1,101 @@
+package gzip
+
+import (
+	"bytes"
+	"compress/gzip"
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHandleGzip(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	tests := []struct {
+		name                    string
+		path                    string
+		acceptEncoding          string
+		expectedContentEncoding string
+		expectedBody            string
+	}{
+		{
+			name:                    "Gzip compression",
+			path:                    "/",
+			acceptEncoding:          "gzip",
+			expectedContentEncoding: "gzip",
+			expectedBody:            "Gzip Test Response",
+		},
+		{
+			name:                    "No compression",
+			path:                    "/",
+			acceptEncoding:          "",
+			expectedContentEncoding: "",
+			expectedBody:            "Gzip Test Response",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			router := gin.New()
+			router.Use(Gzip(DefaultCompression))
+			router.GET("/", func(c *gin.Context) {
+				c.String(http.StatusOK, "Gzip Test Response")
+			})
+
+			req, _ := http.NewRequestWithContext(context.Background(), "GET", tt.path, nil)
+			req.Header.Set("Accept-Encoding", tt.acceptEncoding)
+
+			w := httptest.NewRecorder()
+			router.ServeHTTP(w, req)
+
+			assert.Equal(t, http.StatusOK, w.Code)
+			assert.Equal(t, tt.expectedContentEncoding, w.Header().Get("Content-Encoding"))
+
+			if tt.expectedContentEncoding == "gzip" {
+				gr, err := gzip.NewReader(w.Body)
+				assert.NoError(t, err)
+				defer gr.Close()
+
+				body, _ := io.ReadAll(gr)
+				assert.Equal(t, tt.expectedBody, string(body))
+			} else {
+				assert.Equal(t, tt.expectedBody, w.Body.String())
+			}
+		})
+	}
+}
+
+func TestHandleDecompressGzip(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	buf := &bytes.Buffer{}
+	gz, _ := gzip.NewWriterLevel(buf, gzip.DefaultCompression)
+	if _, err := gz.Write([]byte("Gzip Test Response")); err != nil {
+		gz.Close()
+		t.Fatal(err)
+	}
+	gz.Close()
+
+	router := gin.New()
+	router.Use(Gzip(DefaultCompression, WithDecompressFn(DefaultDecompressHandle)))
+	router.POST("/", func(c *gin.Context) {
+		data, err := c.GetRawData()
+		assert.NoError(t, err)
+		assert.Equal(t, "Gzip Test Response", string(data))
+		c.String(http.StatusOK, "ok")
+	})
+
+	req, _ := http.NewRequestWithContext(context.Background(), "POST", "/", buf)
+	req.Header.Set("Content-Encoding", "gzip")
+
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, "ok", w.Body.String())
+}