Do fuzzer improvements needed for integration test generation (#2316)

Author: IlyaMuravjov

utbot-framework-api/src/main/kotlin/org/utbot/framework/plugin/api/util/IdUtil.kt

@@ -267,6 +267,8 @@ val primitiveByWrapper = mapOf(
 
 val wrapperByPrimitive = primitiveByWrapper.entries.associateBy({ it.value }) { it.key }
 
+fun replaceWithWrapperIfPrimitive(classId: ClassId): ClassId = wrapperByPrimitive[classId] ?: classId
+
 // We consider void primitive here
 // It is sometimes useful even if void is not technically a primitive type
 val primitives = setOf(

utbot-instrumentation/src/main/kotlin/org/utbot/instrumentation/instrumentation/execution/constructors/MockValueConstructor.kt

@@ -330,6 +330,9 @@ class MockValueConstructor(
         //
         // So for such executions we throw `IllegalStateException` that indicates that construction of arguments
         // has failed and causes execution to terminate with `UtConcreteExecutionProcessedFailure` execution result.
+        //
+        // That is also helpful, because it allows to safely use the constructed value where primitive type is expected,
+        // otherwise some models generated by `FieldValueProvider` can lead to false-positive NPEs.
         checkNotNull(result) {
             "Tracked instance can't be null for call ${instantiationExecutableCall.statement} in model $assembleModel"
         }

utbot-java-fuzzing/src/main/kotlin/org/utbot/fuzzing/providers/Field.kt

@@ -8,6 +8,7 @@ import org.utbot.framework.plugin.api.UtDirectGetFieldModel
 import org.utbot.framework.plugin.api.UtNullModel
 import org.utbot.framework.plugin.api.UtReferenceModel
 import org.utbot.framework.plugin.api.util.jClass
+import org.utbot.framework.plugin.api.util.replaceWithWrapperIfPrimitive
 import org.utbot.fuzzer.FuzzedType
 import org.utbot.fuzzer.FuzzedValue
 import org.utbot.fuzzer.IdGenerator
@@ -26,7 +27,9 @@ class FieldValueProvider(
         private val logger = KotlinLogging.logger {}
     }
 
-    override fun accept(type: FuzzedType): Boolean = type.classId == fieldId.type
+    override fun accept(type: FuzzedType): Boolean =
+        replaceWithWrapperIfPrimitive(type.classId).jClass
+            .isAssignableFrom(replaceWithWrapperIfPrimitive(fieldId.type).jClass)
 
     override fun generate(description: FuzzedDescription, type: FuzzedType): Sequence<Seed<FuzzedType, FuzzedValue>> = sequenceOf(
         Seed.Recursive(

utbot-java-fuzzing/src/main/kotlin/org/utbot/fuzzing/providers/Objects.kt

@@ -148,20 +148,24 @@ internal class FieldDescription(
 )
 
 internal fun findAccessibleModifiableFields(description: FuzzedDescription?, classId: ClassId, packageName: String?): List<FieldDescription>  {
-    val jClass = classId.jClass
-    return jClass.declaredFields.map { field ->
-        val setterAndGetter = jClass.findPublicSetterGetterIfHasPublicGetter(field, packageName)
-        FieldDescription(
-            name = field.name,
-            type = if (description != null) toFuzzerType(field.type, description.typeCache) else FuzzedType(field.type.id),
-            canBeSetDirectly = isAccessible(
-                field,
-                packageName
-            ) && !Modifier.isFinal(field.modifiers) && !Modifier.isStatic(field.modifiers),
-            setter = setterAndGetter?.setter,
-            getter = setterAndGetter?.getter,
-        )
-    }
+    return generateSequence(classId.jClass) { it.superclass }.flatMap { jClass ->
+        jClass.declaredFields.map { field ->
+            val setterAndGetter = jClass.findPublicSetterGetterIfHasPublicGetter(field, packageName)
+            FieldDescription(
+                name = field.name,
+                type = if (description != null) toFuzzerType(
+                    field.type,
+                    description.typeCache
+                ) else FuzzedType(field.type.id),
+                canBeSetDirectly = isAccessible(
+                    field,
+                    packageName
+                ) && !Modifier.isFinal(field.modifiers) && !Modifier.isStatic(field.modifiers),
+                setter = setterAndGetter?.setter,
+                getter = setterAndGetter?.getter,
+            )
+        }
+    }.toList()
 }
 
 internal fun Class<*>.findPublicSetterGetterIfHasPublicGetter(field: Field, packageName: String?): PublicSetterGetter? {

utbot-java-fuzzing/src/main/kotlin/org/utbot/fuzzing/providers/Primitives.kt

@@ -215,7 +215,7 @@ object StringValueProvider : PrimitiveValueProvider(stringClassId, java.lang.Cha
             .filter { it.classId == stringClassId }
         val values = constants
             .mapNotNull { it.value as? String } +
-                sequenceOf("", "abc", "\n\t\r")
+                sequenceOf("", "abc", "XZ", "#$\\\"'", "\n\t\r", "10", "-3")
         values.forEach { yieldKnown(StringValue(it), StringValue::value) }
         constants
             .filter { it.fuzzedContext.isPatterMatchingContext()  }