Avoid generating many reflection statements for LinkedHashMap

[EgorkaKulikov]

Description

Try to generate Spring integration tests for spring-boot-testing project OrderController.getAllOrders method.

Generated test looks like not very good, it contains too much reflection.
The problem is that we do not have specific wrappers for LinkedHashMap

 @Test(description = "getAllOrders: ")
    public void testGetAllOrders() throws Exception {
        // begin repository fill up
        Order order = new Order();
        order.setPrice(Double.NEGATIVE_INFINITY);
        order.setQty(Integer.MIN_VALUE);

        // end repository fill up

        ResponseEntity actual = orderController.getAllOrders();

        ResponseEntity expected = ((ResponseEntity) createInstance("org.springframework.http.ResponseEntity"));
        HttpStatus httpStatus = HttpStatus.OK;
        setField(expected, "org.springframework.http.ResponseEntity", "status", httpStatus);
        Object readOnlyHttpHeaders = createInstance("org.springframework.http.ReadOnlyHttpHeaders");
        setField(readOnlyHttpHeaders, "org.springframework.http.ReadOnlyHttpHeaders", "cachedContentType", null);
        setField(readOnlyHttpHeaders, "org.springframework.http.ReadOnlyHttpHeaders", "cachedAccept", null);
        MultiValueMapAdapter multiValueMapAdapter = ((MultiValueMapAdapter) createInstance("org.springframework.util.MultiValueMapAdapter"));
        LinkedCaseInsensitiveMap linkedCaseInsensitiveMap = ((LinkedCaseInsensitiveMap) createInstance("org.springframework.util.LinkedCaseInsensitiveMap"));
        LinkedHashMap anonymousLinkedHashMap = ((LinkedHashMap) createInstance("org.springframework.util.LinkedCaseInsensitiveMap$1"));
        setField(anonymousLinkedHashMap, "org.springframework.util.LinkedCaseInsensitiveMap$1", "this$0", linkedCaseInsensitiveMap);
        setField(anonymousLinkedHashMap, "java.util.LinkedHashMap", "head", null);
        setField(anonymousLinkedHashMap, "java.util.LinkedHashMap", "tail", null);
        setField(anonymousLinkedHashMap, "java.util.LinkedHashMap", "accessOrder", false);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "table", null);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "entrySet", null);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "size", 0);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "modCount", 0);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "threshold", 16);
        setField(anonymousLinkedHashMap, "java.util.HashMap", "loadFactor", 0.75f);
        setField(anonymousLinkedHashMap, "java.util.AbstractMap", "keySet", null);
        setField(anonymousLinkedHashMap, "java.util.AbstractMap", "values", null);
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "targetMap", anonymousLinkedHashMap);
        HashMap hashMap = new HashMap();
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "caseInsensitiveKeys", hashMap);
        Locale locale = ((Locale) createInstance("java.util.Locale"));
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "locale", locale);
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "keySet", null);
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "values", null);
        setField(linkedCaseInsensitiveMap, "org.springframework.util.LinkedCaseInsensitiveMap", "entrySet", null);
        setField(multiValueMapAdapter, "org.springframework.util.MultiValueMapAdapter", "targetMap", linkedCaseInsensitiveMap);
        setField(readOnlyHttpHeaders, "org.springframework.http.HttpHeaders", "headers", multiValueMapAdapter);
        setField(expected, "org.springframework.http.HttpEntity", "headers", readOnlyHttpHeaders);
        ArrayList arrayList = new ArrayList();
        Order order1 = ((Order) createInstance("com.rest.order.models.Order"));
        Long long1 = 2L;
        setField(order1, "com.rest.order.models.Order", "id", long1);
        setField(order1, "com.rest.order.models.Order", "buyer", null);
        Double double1 = Double.NEGATIVE_INFINITY;
        setField(order1, "com.rest.order.models.Order", "price", double1);
        setField(order1, "com.rest.order.models.Order", "qty", Integer.MIN_VALUE);
        arrayList.add(order1);
        setField(expected, "org.springframework.http.HttpEntity", "body", arrayList);
        Object expectedStatus = getFieldValue(expected, "org.springframework.http.ResponseEntity", "status");
        Object actualStatus = getFieldValue(actual, "org.springframework.http.ResponseEntity", "status");
        assertEquals(expectedStatus, actualStatus);

        HttpHeaders expectedHeaders = ((HttpHeaders) getFieldValue(expected, "org.springframework.http.HttpEntity", "headers"));
        HttpHeaders actualHeaders = ((HttpHeaders) getFieldValue(actual, "org.springframework.http.HttpEntity", "headers"));
        // org.springframework.http.HttpHeaders is iterable or Map, use outer deep equals to iterate over
        assertTrue(deepEquals(actualHeaders, expectedHeaders));

        Object expectedBody = getFieldValue(expected, "org.springframework.http.HttpEntity", "body");
        Object actualBody = getFieldValue(actual, "org.springframework.http.HttpEntity", "body");
        assertTrue(deepEquals(actualBody, expectedBody));

    }

[EgorkaKulikov]

The problem is actually not in LinkedHashMap, but in some Spring internal class org.springframework.util.LinkedCaseInsensitiveMap

It seems that we cannot fix such issues in generaral without clever AssembleModelGenerator.
More that that, there are very much different Spring-specific collection wrappers (https://github.com/spring-projects/spring-framework/tree/main/spring-core/src/main/java/org/springframework/util), so I'm not sure we can write special wrappers for all of them.

[IlyaMuravjov]

Can't we just treat all implementations of java.util.Map equally and always construct a HashMap when it comes to constructing expected values? As far as I remember the semantic of equals method that all implementations of java.util.Map should follow is very clearly defined in javadoc, and according to it equality should not depend on the used implementation and the only thing that should matter is the content.

Same goes for java.util.Set and java.util.List for which we can use respectively HashSet and ArrayList as default implementations.

Moreover, such change can be implemented not on the side of code generation, but on the side of value construction in the instrumented process, where it's also possible to check that actualMap is indeed equals to HashMap(actualMap) before replacing a model constructed for actualMap with a model constructed for HashMap(actualMap) to avoid protentional problems with contract breaking implementations like IdentityHashMap.

However, it's also worth noting, that doing anything in instrumented process won't affect tests generated by the symbolic engine without the use of concrete executor.

[EgorkaKulikov]

@sofurihafe Let's discuss this task carefully before starting implementation, there are many potential risks.