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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Test generation fails for Optional\u003cT\u003e class in the plugin","articleBody":"**Description**\r\n\r\nNo test cases are generated for methods involving Java `Optional\u003cT\u003e` class. `UtError`s are generated by the engine during `traverse` due to `ClassNotFound` exception: `UtOptional` class can't be loaded. This behavior may be reproduced using the Idea plugin, but models are successfully generated for the same code in the engine unit tests.\r\n\r\n**To Reproduce**\r\n\r\nGenerate unit tests for the sample method:\r\n\r\n```\r\nimport java.util.Optional;\r\n\r\npublic class OptionalExamples {\r\n    public Optional\u003cInteger\u003e nonEmptyIfPositive(int n) {\r\n        if (n \u003e 0) {\r\n            return Optional.of(n);\r\n        } else {\r\n            return Optional.empty();\r\n        }\r\n    }\r\n}\r\n```\r\n\r\n**Expected behavior**\r\n\r\nTwo tests are generated, one for each branch in the code (see *Additional context* for more details).\r\n\r\n**Actual behavior**\r\n\r\nErrors are reported:\r\n\r\n```\r\npublic class OptionalExamplesTest {\r\n    ///region Test suites for executable collections.OptionalExamples.nonEmptyIfPositive\r\n\r\n\r\n    ///region Errors report for nonEmptyIfPositive\r\n\r\n    public void testNonEmptyIfPositive_errors() {\r\n        // Couldn't generate some tests. List of errors:\r\n        // \r\n        // 2 occurrences of:\r\n        // org.utbot.engine.overrides.collections.UtOptional\r\n\r\n    }\r\n    ///endregion\r\n\r\n    ///endregion\r\n}\r\n```\r\n\r\n**Environment**\r\n\r\nMockito: any configuration. Test framework: JUnit5.\r\n\r\n**Additional context**\r\n\r\nThe primary error reason: `UtOptional` wrapper is used instead of `Optional`, but the class loader used by the test generator in the plugin can't find it. It's OK (engine-specific wrappers should never leak to the user), but `shouldMock` function checks the class and fails with `ClassNotFound` exception.\r\n\r\nAdding a check to `shouldMock` fixes the exception, but the execution path corresponding to `Optional.empty()` return value is lost unless `checkNpeForFinalFields` setting is set to `true` (it is `false` by default). See `SootField.shouldBeNotNull()` declared in `Extensions.kt`.\r\n\r\nA similar code sample that uses `OptionalInt` instead of `Optional\u003cInteger\u003e` is processed without any problems, because primitive field types are never mocked so no class check is performed.\r\n\r\nCode sample:\r\n```\r\npublic OptionalInt nonEmptyOptionalIntIfPositive(int n) {\r\n    if (n \u003e 0) {\r\n        return OptionalInt.of(n);\r\n    } else {\r\n        return OptionalInt.empty();\r\n    }\r\n}\r\n```\r\n\r\nGenerated tests:\r\n```\r\n///region SUCCESSFUL EXECUTIONS for method nonEmptyOptionalIntIfPositive(int)\r\n\r\n/**\r\n * \u003cpre\u003e\r\n * Test executes conditions:\r\n *     {@code (n \u003e 0): True }\r\n * invokes:\r\n *     OptionalInt::of once\r\n * returns from: {@code return OptionalInt.of(n); }\r\n * \u003c/pre\u003e\r\n */\r\n@Test\r\n@DisplayName(\"nonEmptyOptionalIntIfPositive: n \u003e 0 : True -\u003e return OptionalInt.of(n)\")\r\npublic void testNonEmptyOptionalIntIfPositive_NGreaterThanZero() {\r\n    OptionalExamples optionalExamples = new OptionalExamples();\r\n\r\n    OptionalInt actual = optionalExamples.nonEmptyOptionalIntIfPositive(1);\r\n\r\n    OptionalInt expected = of(1);\r\n\r\n    assertTrue(deepEquals(expected, actual));\r\n}\r\n\r\n/**\r\n * \u003cpre\u003e\r\n * Test executes conditions:\r\n *     {@code (n \u003e 0): False }\r\n * \u003c/pre\u003e\r\n */\r\n@Test\r\n@DisplayName(\"nonEmptyOptionalIntIfPositive: -\u003e n \u003e 0 : False\")\r\npublic void testNonEmptyOptionalIntIfPositive_NLessOrEqualZero() throws ClassNotFoundException, Exception {\r\n    Class optionalIntClazz = Class.forName(\"java.util.OptionalInt\");\r\n    OptionalInt prevEMPTY = ((OptionalInt) getStaticFieldValue(optionalIntClazz, \"EMPTY\"));\r\n    try {\r\n        OptionalInt empty = empty();\r\n        setStaticField(optionalIntClazz, \"EMPTY\", empty);\r\n        OptionalExamples optionalExamples = new OptionalExamples();\r\n\r\n        OptionalInt actual = optionalExamples.nonEmptyOptionalIntIfPositive(0);\r\n\r\n\r\n        assertTrue(deepEquals(empty, actual));\r\n    } finally {\r\n        setStaticField(OptionalInt.class, \"EMPTY\", prevEMPTY);\r\n    }\r\n}\r\n///endregion\r\n```\r\n","author":{"url":"https://github.com/dtim","@type":"Person","name":"dtim"},"datePublished":"2022-06-16T15:56:09.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/226/UTBotJava/issues/226"}