diff --git a/proxy/content_test.go b/proxy/content_test.go
new file mode 100644
index 0000000..c2a2dfc
--- /dev/null
+++ b/proxy/content_test.go
@@ -0,0 +1,62 @@
+package proxy
+
+import "testing"
+
+func Test_isTextContentType(t *testing.T) {
+	type args struct {
+		contentType string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "empty content type",
+			args: args{contentType: ""},
+			want: false,
+		},
+		{
+			name: "invalid content type",
+			args: args{contentType: "invalid/contenttype"},
+			want: false,
+		},
+		{
+			name: "text content type",
+			args: args{contentType: "text/plain"},
+			want: true,
+		},
+		{
+			name: "json content type",
+			args: args{contentType: "application/json"},
+			want: true,
+		},
+		{
+			name: "xml content type",
+			args: args{contentType: "application/xml"},
+			want: true,
+		},
+		{
+			name: "javascript content type",
+			args: args{contentType: "application/javascript"},
+			want: true,
+		},
+		{
+			name: "form-urlencoded content type",
+			args: args{contentType: "application/x-www-form-urlencoded"},
+			want: true,
+		},
+		{
+			name: "non-text content type",
+			args: args{contentType: "application/octet-stream"},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isTextContentType(tt.args.contentType); got != tt.want {
+				t.Errorf("isTextContentType() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}