Restore round-to-even behavior.

src/unity.c

@@ -292,7 +292,7 @@ void UnityPrintFloat(const UNITY_DOUBLE input_number)
     else if (isinf(number)) UnityPrint("inf");
     else
     {
-        UNITY_INT32 n = 0;
+        UNITY_INT32 n_int = 0, n;
         int exponent = 0;
         int decimals, digits;
         char buf[16];
@@ -330,16 +330,25 @@ void UnityPrintFloat(const UNITY_DOUBLE input_number)
              * freeing up significant bits in the fractional part.
              */
             UNITY_DOUBLE factor = 1.0f;
-            n = (UNITY_INT32)number;
-            number -= (UNITY_DOUBLE)n;
+            n_int = (UNITY_INT32)number;
+            number -= (UNITY_DOUBLE)n_int;
 
-            while (n < min_scaled) { n *= 10; factor *= 10.0f; exponent--; }
+            while (n_int < min_scaled) { n_int *= 10; factor *= 10.0f; exponent--; }
 
             number *= factor;
         }
 
         /* round to nearest integer */
-        n += ((UNITY_INT32)(number + number) + 1) / 2;
+        n = ((UNITY_INT32)(number + number) + 1) / 2;
+
+#ifndef UNITY_ROUND_TIES_AWAY_FROM_ZERO
+        /* round to even if exactly between two integers */
+        if ((n & 1) && ((UNITY_DOUBLE)n - number == 0.5f))
+            n--;
+#endif
+
+        n += n_int;
+
         if (n >= max_scaled)
         {
             n = min_scaled;

test/tests/testunity.c

@@ -4468,7 +4468,6 @@ void testFloatPrinting(void)
 #else
     TEST_ASSERT_EQUAL_PRINT_FLOATING("0",            0.0f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("4.99e-07",     0.000000499f);
-    TEST_ASSERT_EQUAL_PRINT_FLOATING("5.000001e-07", 0.00000050000005f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("0.1004695",    0.100469499f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("2",            1.9999995f); /*Rounding to int place*/
     TEST_ASSERT_EQUAL_PRINT_FLOATING("1",            1.0f);
@@ -4481,7 +4480,6 @@ void testFloatPrinting(void)
 
     TEST_ASSERT_EQUAL_PRINT_FLOATING("-0",            -0.0f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("-4.99e-07",     -0.000000499f);
-    TEST_ASSERT_EQUAL_PRINT_FLOATING("-5.000001e-07", -0.00000050000005f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("-0.1004695",    -0.100469499f);
     TEST_ASSERT_EQUAL_PRINT_FLOATING("-2",            -1.9999995f); /*Rounding to int place*/
     TEST_ASSERT_EQUAL_PRINT_FLOATING("-1",            -1.0f);
@@ -4512,6 +4510,25 @@ void testFloatPrinting(void)
 #endif
 }
 
+void testFloatPrintingRoundTiesToEven(void)
+{
+#if defined(UNITY_EXCLUDE_FLOAT_PRINT) || defined(UNITY_INCLUDE_DOUBLE) || !defined(USING_OUTPUT_SPY)
+    TEST_IGNORE();
+#else
+  #ifdef UNITY_ROUND_TIES_AWAY_FROM_ZERO
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("0.0004882813",  0.00048828125f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("488281.3",      488281.25f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("5.000001e-07",  0.00000050000005f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("-5.000001e-07", -0.00000050000005f);
+  #else /* Default to Round ties to even */
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("0.0004882812",  0.00048828125f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("488281.2",      488281.25f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("5e-07",         0.00000050000005f);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("-5e-07",        -0.00000050000005f);
+  #endif
+#endif
+}
+
 void testFloatPrintingInfinityAndNaN(void)
 {
 #if defined(UNITY_EXCLUDE_FLOAT_PRINT) || !defined(USING_OUTPUT_SPY)
@@ -4529,31 +4546,15 @@ void testFloatPrintingInfinityAndNaN(void)
 static void printFloatValue(float f)
 {
     char expected[18];
-    char expected_lower[18];
-    char expected_higher[18];
 
     startPutcharSpy();
-
     UnityPrintFloat(f);
 
     sprintf(expected, "%.9g", f);
-
     /* We print all NaN's as "nan", not "-nan" */
-    if(strcmp(expected, "-nan") == 0) strcpy(expected, "nan");
-
-    strcpy(expected_lower, expected);
-    strcpy(expected_higher, expected);
-
-    /* Allow for rounding differences in the last digit */
-    double lower = (double)f * 0.9999999995;
-    double higher = (double)f * 1.0000000005;
-
-    if(isfinite(lower)) sprintf(expected_lower, "%.9g", lower);
-    if(isfinite(higher)) sprintf(expected_higher, "%.9g", higher);
+    if (strcmp(expected, "-nan") == 0) strcpy(expected, "nan");
 
-    if (strcmp(expected, getBufferPutcharSpy()) != 0 &&
-        strcmp(expected_lower, getBufferPutcharSpy()) != 0 &&
-        strcmp(expected_higher, getBufferPutcharSpy()) != 0)
+    if (strcmp(expected, getBufferPutcharSpy()))
     {
         /* Fail with diagnostic printing */
         TEST_ASSERT_EQUAL_PRINT_FLOATING(expected, f);
@@ -4571,13 +4572,11 @@ static void printFloatValue(float f)
     char expected_higher3[18];
 
     startPutcharSpy();
-
     UnityPrintFloat(f);
 
     sprintf(expected, "%.7g", f);
-
     /* We print all NaN's as "nan", not "-nan" */
-    if(strcmp(expected, "-nan") == 0) strcpy(expected, "nan");
+    if (strcmp(expected, "-nan") == 0) strcpy(expected, "nan");
 
     strcpy(expected_lower, expected);
     strcpy(expected_lower2, expected);
@@ -4594,17 +4593,17 @@ static void printFloatValue(float f)
     if(isfinite(higher)) sprintf(expected_higher, "%.7g", higher);
 
     /* Outside [1,10000000] allow for relative error of +/-2.5e-7 */
-    if(f < 1.0 || f > 10000000)
+    if (f < 1.0 || f > 10000000)
     {
         double lower2 = (double)f * 0.99999985;
         double lower3 = (double)f * 0.99999975;
         double higher2 = (double)f * 1.00000015;
         double higher3 = (double)f * 1.00000025;
 
-        if(isfinite(lower2)) sprintf(expected_lower2, "%.7g", lower2);
-        if(isfinite(lower3)) sprintf(expected_lower3, "%.7g", lower3);
-        if(isfinite(higher2)) sprintf(expected_higher2, "%.7g", higher2);
-        if(isfinite(higher3)) sprintf(expected_higher3, "%.7g", higher3);
+        if (isfinite(lower2)) sprintf(expected_lower2, "%.7g", lower2);
+        if (isfinite(lower3)) sprintf(expected_lower3, "%.7g", lower3);
+        if (isfinite(higher2)) sprintf(expected_higher2, "%.7g", higher2);
+        if (isfinite(higher3)) sprintf(expected_higher3, "%.7g", higher3);
     }
 
     if (strcmp(expected, getBufferPutcharSpy()) != 0 &&
@@ -5362,6 +5361,21 @@ void testDoublePrinting(void)
 #endif
 }
 
+void testDoublePrintingRoundTiesToEven(void)
+{
+#if defined(UNITY_EXCLUDE_FLOAT_PRINT) || defined(UNITY_EXCLUDE_DOUBLE) || !defined(USING_OUTPUT_SPY)
+    TEST_IGNORE();
+#else
+  #ifdef UNITY_ROUND_TIES_AWAY_FROM_ZERO
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("1.00000001e+10", 10000000050.0);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("9.00719925e+15", 9007199245000000.0);
+  #else /* Default to Round ties to even */
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("1e+10",          10000000050.0);
+    TEST_ASSERT_EQUAL_PRINT_FLOATING("9.00719924e+15", 9007199245000000.0);
+  #endif
+#endif
+}
+
 void testDoublePrintingInfinityAndNaN(void)
 {
 #if defined(UNITY_EXCLUDE_FLOAT_PRINT) || defined(UNITY_EXCLUDE_DOUBLE) || !defined(USING_OUTPUT_SPY)