CQ. Use assertDartObjectText() with raw multi-line string in more places.

Replace ad hoc assertions over DartObjectImpl with
assertDartObjectText() in constant evaluation and resolution tests. This
makes the expected constant value shape explicit, including invalid
results, variables, constructor invocations, type arguments, and
superclass fields, instead of checking only selected fields.

Use raw multi-line strings for these expectations so expected text can
be copied and maintained consistently without escaping interpolation or
other Dart string syntax.

Remove the now-unused null assertion helper and analyzer implementation
imports that were only needed by the direct assertions.

Change-Id: Ib734c1d428dd69104403484534b60af918944d13
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/508705
Reviewed-by: Paul Berry <paulberry@google.com>

pkg/analyzer/test/src/dart/resolution/constant_test.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/src/dart/constant/value.dart';
-import 'package:analyzer/src/dart/element/element.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -41,7 +39,9 @@ const a = const A();
     // To evaluate `const A()` we have to evaluate `{int p}`.
     // Even if its value is `null`.
     expect(p.isConstantEvaluated, isTrue);
-    expect(p.computeConstantValue()!.isNull, isTrue);
+    assertDartObjectText(p.computeConstantValue(), r'''
+Null null
+''');
   }
 
   test_constFactoryRedirection_super() async {
@@ -66,7 +66,19 @@ main() {}
 
     var node = result.findNode.annotation('@I');
     var value = node.elementAnnotation!.computeConstantValue()!;
-    expect(value.getField('(super)')!.getField('f')!.toIntValue(), 42);
+    assertDartObjectText(value, r'''
+B
+  (super): A
+    f: int 42
+    constructorInvocation
+      constructor: <testLibrary>::@class::A::@constructor::new
+      positionalArguments
+        0: int 42
+  constructorInvocation
+    constructor: <testLibrary>::@class::I::@constructor::new
+    positionalArguments
+      0: int 42
+''');
   }
 
   test_constList_withNullAwareElement() async {
@@ -212,7 +224,10 @@ import 'a.dart';
 
     var import_ = result.findElement.importFind('package:test/a.dart');
     var a = import_.topVar('a');
-    expect(a.computeConstantValue()!.toIntValue(), 42);
+    assertDartObjectText(a.computeConstantValue(), r'''
+int 42
+  variable: package:test/a.dart::@topLevelVariable::a
+''');
   }
 
   test_imported_prefixedIdentifier_staticField_extension() async {
@@ -231,7 +246,10 @@ import 'a.dart';
 
     var import_ = result.findElement.importFind('package:test/a.dart');
     var a = import_.topVar('a');
-    expect(a.computeConstantValue()!.toIntValue(), 42);
+    assertDartObjectText(a.computeConstantValue(), r'''
+int 42
+  variable: package:test/a.dart::@topLevelVariable::a
+''');
   }
 
   test_imported_prefixedIdentifier_staticField_mixin() async {
@@ -252,7 +270,10 @@ import 'a.dart';
 
     var import_ = result.findElement.importFind('package:test/a.dart');
     var a = import_.topVar('a');
-    expect(a.computeConstantValue()!.toIntValue(), 42);
+    assertDartObjectText(a.computeConstantValue(), r'''
+int 42
+  variable: package:test/a.dart::@topLevelVariable::a
+''');
   }
 
   test_imported_super_defaultFieldFormalParameter() async {
@@ -281,10 +302,18 @@ class B extends A {
     });
     var aResult = results[a]!;
 
-    var bElement = aResult.findElement.field('b') as FieldElementImpl;
-    var bValue = bElement.evaluationResult as DartObjectImpl;
-    var superFields = bValue.getField(GenericState.SUPERCLASS_FIELD);
-    expect(superFields!.getField('f1')!.toBoolValue(), false);
+    var bElement = aResult.findElement.field('b');
+    assertDartObjectText(bElement.computeConstantValue(), r'''
+B
+  (super): A
+    f1: bool false
+    f2: bool false
+    constructorInvocation
+      constructor: package:test/a.dart::@class::A::@constructor::new
+  constructorInvocation
+    constructor: <testLibrary>::@class::B::@constructor::new
+  variable: package:test/a.dart::@class::A::@field::b
+''');
   }
 
   test_local_prefixedIdentifier_staticField_extension() async {
@@ -296,6 +325,9 @@ extension E on int {
 }
 ''');
     var a = result.findElement.topVar('a');
-    expect(a.computeConstantValue()!.toIntValue(), 42);
+    assertDartObjectText(a.computeConstantValue(), r'''
+int 42
+  variable: <testLibrary>::@topLevelVariable::a
+''');
   }
 }