Add tests for valyala#87

Tests for string escape conformance with standard lib

Author: klondikedragon

parser_test.go

@@ -1,6 +1,8 @@
 package fastjson
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"math"
 	"strings"
@@ -68,6 +70,40 @@ func TestParseRawNumber(t *testing.T) {
 	})
 }
 
+func TestEscapeString(t *testing.T) {
+	t.Run("controlchars", func(t *testing.T) {
+		var r rune
+		for r = 0; r <= 0x20; r++ {
+			testEscapeString(t, string(r))
+			testEscapeString(t, string(r)+" hello")
+			testEscapeString(t, "hello "+string(r))
+			testEscapeString(t, "hello "+string(r)+" world")
+		}
+	})
+	t.Run("misc", func(t *testing.T) {
+		testEscapeString(t, `hello � world`)
+		testEscapeString(t, "hello \u0014 world")
+		testEscapeString(t, "newline\ntab\ndoublequote\"reversesolidus\\solidus/formfeed\fcarriagereturn\r")
+	})
+	t.Run("unicode", func(t *testing.T) {
+		testEscapeString(t, `你好，世界`)
+		testEscapeString(t, "こんにちは、世界")
+		testEscapeString(t, "ສະບາຍດີ, ໂລກ")
+	})
+}
+
+func testEscapeString(t *testing.T, s string) {
+	t.Helper()
+
+	// Check that fastjson encoding is identical to standard library encoding
+	expected, _ := json.Marshal(s)
+	a := Arena{}
+	actual := a.NewString(s).MarshalTo(nil)
+	if !bytes.Equal(actual, expected) {
+		t.Fatalf("expected='%s', actual='%s'", expected, actual)
+	}
+}
+
 func TestUnescapeStringBestEffort(t *testing.T) {
 	t.Run("success", func(t *testing.T) {
 		testUnescapeStringBestEffort(t, ``, ``)
@@ -349,7 +385,7 @@ func TestValueGetTyped(t *testing.T) {
 	}
 	un64 = v.GetUint64("bar")
 	if n != 0 {
-		t.Fatalf("unexpected non-zero value; got %d", n64)
+		t.Fatalf("unexpected non-zero value; got %d", un64)
 	}
 	f := v.GetFloat64("foo")
 	if f != 123.0 {