Fixed filtering lambda types

Author: Damtev

utbot-framework-test/src/test/kotlin/org/utbot/examples/lambda/PredicateNotExampleTest.kt

@@ -0,0 +1,17 @@
+package org.utbot.examples.lambda
+
+import org.junit.jupiter.api.Test
+import org.utbot.testcheckers.eq
+import org.utbot.tests.infrastructure.UtValueTestCaseChecker
+
+class PredicateNotExampleTest : UtValueTestCaseChecker(testClass = PredicateNotExample::class) {
+    @Test
+    fun testPredicateNotExample() {
+        check(
+            PredicateNotExample::predicateNotExample,
+            eq(2),
+            { a, r -> a == 5 && r == false },
+            { a, r -> a != 5 && r == true },
+        )
+    }
+}

utbot-framework/src/main/kotlin/org/utbot/engine/TypeResolver.kt

@@ -206,9 +206,7 @@ class TypeResolver(private val typeRegistry: TypeRegistry, private val hierarchy
             when {
                 sootClass.isUtMock -> unwantedTypes += it
                 sootClass.isArtificialEntity -> {
-                    if (sootClass.isLambda) {
-                        unwantedTypes += it
-                    } else if (keepArtificialEntities) {
+                    if (keepArtificialEntities || sootClass.isLambda) {
                         concreteTypes += it
                     }
                 }

utbot-sample/src/main/java/org/utbot/examples/lambda/PredicateNotExample.java

@@ -0,0 +1,13 @@
+package org.utbot.examples.lambda;
+
+import java.util.function.*;
+
+public class PredicateNotExample {
+    public boolean predicateNotExample(int a) {
+        if (Predicate.not(i -> i.equals(5)).test(a)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+}