test: cast negative zero to string

docs/source/user-guide/latest/compatibility.md

@@ -153,13 +153,6 @@ Cast operations in Comet fall into three levels of support:
   Spark.
 - **N/A**: Spark does not support this cast.
 
-### Negative Zero
-
-When casting floating-point values to strings, Spark normalizes negative zero (`-0.0`) to `"0.0"`, but Comet
-may produce `"-0.0"`. Since negative zero and positive zero are semantically equivalent (`-0.0 == 0.0` is true
-in IEEE 754), this difference is unlikely to affect real-world results. See
-[#1036](https://github.com/apache/datafusion-comet/issues/1036) for more details.
-
 ### Legacy Mode
 
 <!--BEGIN:CAST_LEGACY_TABLE-->

spark/src/test/scala/org/apache/comet/CometCastSuite.scala

@@ -498,6 +498,7 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
       -1.0f,
       Short.MinValue.toFloat,
       Short.MaxValue.toFloat,
+      -0.0f,
       0.0f) ++
       Range(0, dataSize).map(_ => r.nextFloat())
     castTest(withNulls(values).toDF("a"), DataTypes.StringType)
@@ -558,6 +559,11 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
       Double.NaN,
       Double.PositiveInfinity,
       Double.NegativeInfinity,
+      1.0d,
+      -1.0d,
+      Int.MinValue.toDouble,
+      Int.MaxValue.toDouble,
+      -0.0d,
       0.0d) ++
       Range(0, dataSize).map(_ => r.nextDouble())
     castTest(withNulls(values).toDF("a"), DataTypes.StringType)