From 7274fa4dd4b8666c88ae54d4874057ea915e030d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?D=C3=A1niel=20B=C3=A1tyai?= <dbatyai@inf.u-szeged.hu>
Date: Mon, 18 May 2020 18:39:00 +0200
Subject: [PATCH] Fix rounding in Number.prototype.toFixed (#3747)
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Fixes #3741.

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu
---
 .../ecma-builtin-number-prototype.c           |  3 +-
 tests/jerry/number-prototype-to-fixed.js      | 32 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-number-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-number-prototype.c
index e913450ba..aaeecb675 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-number-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-number-prototype.c
@@ -673,6 +673,7 @@ ecma_builtin_number_prototype_object_to_fixed (ecma_number_t this_num, /**< this
   if (!ecma_number_is_zero (this_num))
   {
     num_digits = ecma_number_to_binary_floating_point_number (this_num, digits, &exponent);
+    JERRY_ASSERT (exponent >= 0);
   }
   else
   {
@@ -692,7 +693,7 @@ ecma_builtin_number_prototype_object_to_fixed (ecma_number_t this_num, /**< this
 
   /* 8. */
   num_digits = ecma_builtin_number_prototype_helper_round (digits,
-                                                           num_digits + 1,
+                                                           num_digits + (lit_utf8_size_t) exponent,
                                                            exponent + frac_digits,
                                                            &exponent,
                                                            ecma_number_is_zero (this_num));
diff --git a/tests/jerry/number-prototype-to-fixed.js b/tests/jerry/number-prototype-to-fixed.js
index 67d5ed1bf..637296cd4 100644
--- a/tests/jerry/number-prototype-to-fixed.js
+++ b/tests/jerry/number-prototype-to-fixed.js
@@ -63,3 +63,35 @@ try {
 } catch (e) {
     assert(e instanceof RangeError)
 }
+
+assert ((0.5).toFixed(0) === "1");
+assert ((1.5).toFixed(0) === "2");
+assert ((12.5).toFixed(0) === "13");
+assert ((123.5).toFixed(0) === "124");
+assert ((1234.5).toFixed(0) === "1235");
+assert ((0.567).toFixed(0) === "1");
+assert ((1.567).toFixed(0) === "2");
+assert ((12.567).toFixed(0) === "13");
+assert ((123.567).toFixed(0) === "124");
+assert ((1234.567).toFixed(0) === "1235");
+
+assert ((1.2567).toFixed(0) === "1");
+assert ((1.2567).toFixed(1) === "1.3");
+assert ((1.2567).toFixed(2) === "1.26");
+assert ((1.2567).toFixed(3) === "1.257");
+assert ((1.2567).toFixed(4) === "1.2567");
+assert ((1.2567).toFixed(5) === "1.25670");
+
+assert ((12.3567).toFixed(0) === "12");
+assert ((12.3567).toFixed(1) === "12.4");
+assert ((12.3567).toFixed(2) === "12.36");
+assert ((12.3567).toFixed(3) === "12.357");
+assert ((12.3567).toFixed(4) === "12.3567");
+assert ((12.3567).toFixed(5) === "12.35670");
+
+assert ((123.4567).toFixed(0) === "123");
+assert ((123.4567).toFixed(1) === "123.5");
+assert ((123.4567).toFixed(2) === "123.46");
+assert ((123.4567).toFixed(3) === "123.457");
+assert ((123.4567).toFixed(4) === "123.4567");
+assert ((123.4567).toFixed(5) === "123.45670");